A level switch becomes difficult when the media is not simple water

Detecting a high or low level in a clean water tank is usually straightforward. The real selection problem starts when the same switch has to work with yoghurt, syrup, foam, powder, condensation, product coating or a hygienic process that gets cleaned regularly.

That is where buyers often make the wrong assumption about capacitive level switches.

They look at the connection size and output signal, then select a model. But with capacitance based level detection, the medium, dielectric constant, mounting, process connection and behaviour of material around the sensing tip matter just as much.

Baumer's CleverLevel range addresses this type of point level detection with the LBFS capacitive point level sensor and the LFFS CleverLevel switch. Both work with media having a dielectric constant above 1.5, but their configuration options and application possibilities are not identical.

What is a Baumer capacitive level switch?

A capacitive level switch detects whether material is present or absent at a fixed point in a tank, pipe or vessel.

It does not tell you that a tank is 42 percent full. That would require continuous level measurement. Instead, a point level switch answers a simpler but important question:

Has the product reached this point or not?

This signal can then be used for functions such as:

• High level alarm
• Low level alarm
• Tank overfill protection
• Pump dry run protection
• Empty pipe detection
• Product presence detection
• Media separation
• Automatic filling or emptying logic

Baumer uses its CleverLevel measuring principle for these applications.

How does CleverLevel actually work?

This is one of the useful details hidden behind the word "capacitive."

The measuring principle diagram on page 2 of the LFFS operating instructions shows an electrode inside the sensing tip forming a capacitor together with its surroundings. When the process medium changes, its dielectric constant changes the capacitance. The electronics combine this behaviour with a resonance circuit and evaluate the resulting frequency against programmed switching thresholds.

The LBFS datasheet describes this as CleverLevel Frequency Sweep technology.

In practical terms, the sensor is not simply waiting for electrical contact with the product. It evaluates how the electromagnetic behaviour around the sensing tip changes when product is present.

This makes the technology useful across very different media, provided the actual product and installation conditions are considered during selection.

Baumer CleverLevel LBFS

The Baumer LBFS is a compact capacitive point level sensor intended for both industrial and hygienic applications.

It makes sense when you need a small stainless steel point level device that can be mounted from the side, top or bottom of a tank or process connection and connected directly into an automation system.

The datasheet also specifies mounting from the top, bottom or side. Its wetted materials include PEEK and stainless steel, with AISI 316L as a primary option.

Technical points to note:

• Measuring principle: CleverLevel Frequency Sweep
• Media dielectric constant: above 1.5
• Repeatability: ±1 mm
• Hysteresis: ±1 mm
• Typical response time: 0.1 second
• Adjustable damping: 0 to 10 seconds
• Output configurations: PNP or NPN
• Switching logic: normally open or normally closed
• Supply: 12 to 30 V DC
• Protection: IP67 or IP69K with the appropriate cable
• Electrical options include M12 connector or cable versions

The LBFS product overview also lists marine, WHG and cULus approvals, with optional explosion protected configurations. Exact approvals depend on the selected ordering variant.

Where it is commonly used:

• Food and beverage tanks
• Dairy processing equipment
• Pharma and hygienic skids
• Water and utility tanks
• Process piping
• OEM filling equipment
• Pump protection
• High and low level alarms

For that reason, the complete ordering code matters.

Baumer CleverLevel LFFS

The Baumer LFFS is useful when the application requires more adjustment around difficult media or process behaviour.

The operating instructions specifically describe applications including tank level detection, media separation, empty pipe detection and pump dry run protection. The sensor can work with liquids such as water and beer, viscous or sticky products such as honey and yoghurt, and dry products such as sugar and flour.

The LFFS gives the engineer more control over that problem. Using Baumer's FlexProgrammer 9701 and Flex software, the output can be configured as PNP, NPN or digital, and the sensor can be adjusted for a particular medium. The manual also describes compensation settings for foam, bubbles, condensate and viscous media.

Technical points to note:

• Suitable for liquids and solids with dielectric constant above 1.5
• Outputs configurable as PNP, NPN or digital
• Supply: 12.5 to 36 V DC
• Output load: maximum 50 mA
• Adjustable output damping
• FlexProgrammer 9701 configuration support
• Teach in capability for empty and full conditions
• Hygienic installation options
• Resistant to CIP and SIP agents
• WHG certified for leakage and overfill protection

Where it is commonly used:

• Sticky food products
• Dairy tanks
• Beverage systems
• Powder and dry material detection
• Pump dry run protection
• Empty pipe detection
• High level protection
• Media separation applications

The LFFS instructions specifically warn that if sticky, foamy or powdery product remains around the tip during normal operation, that condition should also be present during teach in. Otherwise the calibration can be incorrect.

That is a practical point worth paying attention to during commissioning.

LBFS vs LFFS: Which Baumer level switch should you choose?

The decision should not simply be "LBFS is smaller" or "LFFS has more settings."

The better question is:

How predictable is your process medium?

For straightforward point level switching with a suitable process connection and PNP or NPN output, the LBFS can be a very practical choice.

If your process involves product coating, foam, condensation, powders or changing media conditions where sensitivity needs to be tuned, the LFFS configuration capability becomes more important.

Key Selection Factors for Baumer Capacitive Level Switches

1. Check the dielectric constant

Both product documents specify applications with media having a dielectric constant above 1.5.

If your medium is unusual or close to the switching limit, confirm suitability before ordering.

2. Understand what the sensor will really see

Do not evaluate only the bulk product.

Ask whether the tip will also see:

• Foam
• Condensation
• Product coating
• Bubbles
• Sticky residue
• Powder build up

These conditions may affect commissioning and switching behaviour.

3. Confirm the process connection

The LBFS range includes multiple threaded, NPT, hygienic, cooling neck and sliding configurations.

For hygienic installations, Baumer notes that 3 A and EHEDG requirements depend on using the appropriate mounting accessories.

4. Confirm PLC input compatibility

If the switch is going into a PLC, relay module or control panel, confirm whether the input expects PNP or NPN logic.

Do not assume that every level switch can simply replace another model with the same connection thread.

5. Check actual process temperature and pressure

This is especially important with LBFS because the operating conditions table changes according to the exact connection and sensor construction.

Some special LBFS arrangements use cooling necks or sliding connections for higher process temperatures. Confirm the full ordering code instead of relying only on the general product overview.

6. Check whether hazardous area approval is required

LBFS is available with selected IECEx, CCC and ATEX configurations. The LFFS documentation also covers versions for hazardous gas and dust applications. Approval requirements must be matched to the exact area classification and device variant.

7. Do not ignore installation details

The LFFS manual makes several installation points that are easy to miss. The sensor should be installed in a closed metal pipe, tank or container, and the sensor tip needs the correct relationship to the surrounding metal for the measuring principle to work as intended. Hygienic installations also require the correct adapter and orientation.

Common Applications

Baumer capacitive level switches can fit applications such as tank high level detection, low level alarms, pump protection, empty pipe detection, dry media presence detection, process vessel switching, food product tanks and hygienic production equipment.

The LFFS documentation is particularly useful here because it gives real examples rather than simply saying "liquids and solids." It specifically lists water, beer, honey, yoghurt, toothpaste, ketchup, sugar and flour.

That range gives a good idea of why CleverLevel is interesting for applications where one plant may handle both thin liquids and products that leave residue on conventional probes.

Common Mistakes to Avoid

Quick Selection Checklist

Before ordering a Baumer capacitive level switch, confirm:

1. Product or media name
2. Liquid, powder or sticky material
3. Dielectric constant if known
4. High level, low level, dry run or empty pipe application
5. PNP, NPN or other required switching output
6. Normally open or normally closed logic
7. PLC, relay or control system connection
8. Process connection
9. Tank or pipe mounting position
10. Process temperature
11. Process pressure
12. Hygienic requirement
13. CIP or SIP requirement
14. IP protection
15. Hazardous area certification
16. Need for teach in or media adjustment

Specifications to Confirm Before Purchase

Baumer offers many combinations, particularly within the LBFS ordering system. Final specification should therefore be checked against the exact selected variant.

Confirm the process connection, wetted material, temperature rating, pressure limit, supply voltage, switching output, cable or M12 connection, IP rating, hygienic approval, explosion protection, sensor length and mounting accessory before placing the order.

Why Buy Baumer Level Switches from Radical TechMart?

The difficult part of buying a level switch is usually not finding the model number. It is deciding whether that model will behave correctly once it sees the actual product inside the tank.

At Radical TechMart, the selection discussion can start from the application: media, tank, temperature, pressure, PLC input, hygiene requirement and required switching function.

This is particularly useful with products such as LBFS and LFFS because several sensor, connection and approval configurations are available.

Final Thoughts

A Baumer capacitive level switch should be selected around the process, not only around the thread size.

For a compact industrial or hygienic point level application, the LBFS gives a broad range of connection and configuration possibilities. For more demanding media behaviour where foam, coating, powder or changing process conditions need to be considered during commissioning, the LFFS offers useful teach in and FlexProgrammer adjustment capabilities.

In practical plant work, the best level switch is the one that still switches correctly after the process has been running for weeks, not just the one that works during the first water test.

FAQs

1. What is the Baumer LBFS?

The LBFS is a Baumer CleverLevel capacitive point level sensor for industrial and hygienic applications. It uses Frequency Sweep measurement and supports PNP or NPN switching configurations.

2. What is the Baumer LFFS used for?

The LFFS can be used for tank level detection, media separation, empty pipe detection and pump dry run protection. It supports liquids, sticky products and dry media with dielectric constant above 1.5.

3. Can Baumer CleverLevel detect powders?

Yes. The LFFS manual specifically gives sugar and flour as examples of dry media that can be detected. Suitability still depends on dielectric properties and installation conditions.

4. Can a Baumer capacitive level switch connect to a PLC?

Yes. LBFS is available with PNP or NPN output configurations. LFFS can be configured for PNP, NPN or digital output. The PLC input type and wiring must be confirmed before installation.

5. Is CleverLevel suitable for sticky products?

The LFFS documentation specifically mentions viscous and sticky products including honey, yoghurt, toothpaste and ketchup. It also provides media adjustment and teach in functions for difficult operating conditions.

6. Can the sensor be used in hygienic applications?

Yes, suitable LBFS and LFFS configurations support hygienic installations. For certifications such as 3 A or EHEDG, the appropriate mounting accessories and installation method must also be used.

7. Is Baumer LBFS suitable for high temperature applications?

Selected LBFS variants use cooling necks, extended hygienic connections or sliding connections for elevated process temperatures. The allowable limit depends on the exact ordering configuration, so the operating conditions table should be checked before selection.

8. What is the difference between LBFS and LFFS?

Both are CleverLevel point level devices for media with dielectric constant above 1.5. LBFS is a compact configurable sensor family with extensive connection choices, while LFFS documentation places greater emphasis on teach in, FlexProgrammer configuration and compensation for challenging media conditions.

A tank has to stop filling before it overflows. A pump should not continue running when the liquid level becomes too low. A process vessel needs a high-level alarm. A wastewater sump needs automatic pump control.

All of these sound like straightforward level switching applications.

The mistake happens when the buyer simply asks for a "float switch" without considering how the switch will be mounted, what liquid is inside the vessel, operating temperature, pressure, required switching point and installation environment.

A cable float hanging inside a water tank and a stainless steel side-mounted float fitted into a process vessel perform the same basic job, but they are meant for very different installations.

Within the Baumer float level switch range covered by the available datasheets, this difference is clearly seen between the LZ Cable Float Level Switch and the LA Side Mounted Level Switch. The LZ is designed around a suspended polypropylene float and cable arrangement, while the LA uses a side-mounted float mechanism with AISI 316 stainless steel wetted parts and a magnetic switching principle.

That distinction should be the starting point of selection.

What Is a Baumer Float Level Switch?

A float level switch detects whether liquid has reached a particular level and changes an electrical contact accordingly.

Unlike a continuous level transmitter, it does not tell the control system that the tank is 42% or 78% full. Its job is to give a switching condition such as:

In a typical control panel, this switching contact can become part of a relay, contactor, alarm or PLC digital input circuit, depending on the electrical design.

The important question is therefore not only, "Do I need a float switch?"

It is, "What type of float switch suits this vessel and process?"

Baumer LZ Cable Float Level Switch

The LZ is the simpler choice when the float can hang freely inside a tank, sump or reservoir.

As the liquid rises or falls, the float tilts. That movement operates an internal microswitch and changes the contact from normally open to normally closed or vice versa. Baumer also shows the LZ being used for filling control and pump protection, which makes its intended use very clear.

Best for:

Water tanks, sewage tanks, reservoirs, sumps and automatic pump control applications where a suspended cable float can move freely with liquid level.

Why the LZ makes sense

The strength of the LZ is simplicity.

You do not need a side process flange penetrating the vessel. The float is suspended from its cable, and the adjustable counterweight helps define how the float moves around the required switching level.

This makes it practical for larger tanks where the level differential does not need to be extremely tight.

Its polypropylene construction also suits the water and sewage applications identified in the datasheet. The enclosure is IP68, which is particularly relevant because the float operates directly in the liquid environment.

Technical points to note

Baumer notes that cable lengths above 20 metres should be discussed with the factory.

Where the LZ is commonly used

Its datasheet specifically identifies sewage and water treatment plants, storage tanks and automatic pump control utilities. The same operating principle makes it relevant wherever a freely suspended float can be used for high or low level switching.

For example, in a sump pump application, one LZ can be positioned to create the required switching point. Where multiple level points are necessary, the datasheet also states that the LZ can be used as a multipoint switch arrangement.

Selection caution

Do not select the LZ simply because the application contains water.

Check whether the float has enough free space to move without hitting a wall, ladder, pipe, agitator or other internal structure. Also confirm liquid temperature and pressure because the standard version is specified up to 60°C and 4 bar.

For compact vessels requiring a precise side switching point, the LA arrangement may make more sense.

Baumer LA Side Mounted Float Level Switch

The LA belongs to a different class of installation.

Instead of hanging from a cable, it is fitted through the side of the vessel. A free-moving float operates a magnetic mechanism. The datasheet describes two magnets, one associated with the float arm and another in the switch enclosure. Changing liquid level brings the magnetic poles into a position where repulsion produces a snap-action changeover contact.

Best for:

Process tanks and vessels where a defined side-mounted level point is required, particularly where stainless steel wetted parts, higher temperature capability or higher operating pressure are needed.

Why the LA makes sense

A side-mounted switch gives the engineer a defined physical switching location.

If the requirement is "give me a high-level alarm at this nozzle" rather than "switch somewhere across this suspended cable travel," a side-mounted design is generally much easier to engineer into the vessel.

The standard LA uses AISI 316 stainless steel wetted parts, a 92 mm PCD square flange and a 215 mm standard insertion depth. Its standard operating specification extends from -10°C to +180°C with a maximum pressure of 18 kg/cm² and a minimum liquid specific gravity of 0.75.

That immediately places it in a different application range from the LZ.

Technical points to note

Where the LA is commonly used

Baumer identifies applications including chemical processing equipment, alarms for hydro-pneumatic tanks, shipbuilding, water treatment plants, food and pharmaceutical applications.

These applications make sense because the LA is designed around a process-mounted construction rather than a freely suspended plastic float.

LA variants matter when the standard model is not enough

The LA family is not limited to one configuration.

Baumer lists:

Type A: General-purpose standard version

Type T: High-temperature version, up to 350°C, using aluminium cooling fins

Type Z: Adjustable differential version

The minimum insertion depth is 215 mm for Types A and T, while Type Z starts from 350 mm. The ordering information also provides alternatives for housing, cable glands, switch output and process connections. Standard switch output is 1 SPDT, with 2 SPDT / 1 DPDT available as another listed configuration.

This is useful in projects where the requirement is more specific than a standard high or low level switch.

Selection caution

The minimum specific gravity of 0.75 must not be ignored.

A float works only when the liquid can provide sufficient buoyancy. Before ordering the LA, Baumer specifically asks for the liquid, specific gravity, operating pressure and operating temperature along with the model information.

That is good purchasing practice even when replacing an existing switch.

Baumer LA vs LZ: Which Float Level Switch Should You Choose?

In simple words, choose the LZ when you need a practical cable float inside a tank. Choose the LA when you need an engineered switching point on the side of a process vessel.

Key Selection Factors for a Baumer Float Level Switch

1. Start With the Tank, Not the Model Number

First determine whether the vessel allows a freely hanging float.

A large water storage tank or sump may suit an LZ very well. A compact process vessel with a dedicated side nozzle naturally points toward the LA.

2. Check the Liquid

For the LA, specific gravity matters because the standard minimum is 0.75. Also consider whether the wetted material is compatible with the liquid. The standard LA uses AISI 316 SS wetted parts, while the LZ uses a polypropylene float.

3. Check Temperature Before Anything Else

This is one of the easiest ways to separate the two products.

An application near ambient water temperature is very different from a hot process vessel.

The LZ standard version is specified up to 60°C. The LA standard version reaches +180°C, while the Type T configuration is listed for temperatures up to 350°C.

4. Confirm Operating Pressure

Do not use tank dimensions as a substitute for pressure information.

The LZ standard specification lists a maximum operating pressure of 4 bar. The LA standard version lists 18 kg/cm².

5. Decide the Required Switching Differential

A pump control application may intentionally need significant difference between ON and OFF levels to avoid rapid cycling.

A process alarm may require a much more defined switching point.

This is where the physical arrangement of LZ and LA becomes important.

6. Confirm the Electrical Circuit

Both products provide switch contacts rather than a continuous analogue level signal.

Before connecting the switch to a PLC, relay or pump control circuit, confirm the required contact logic, voltage and current. The LZ is listed as SPDT rated 16 A at 250 VAC, while the standard LA microswitch is rated 5 A at 250 VAC.

Common Mistakes to Avoid

The most common mistake is ordering by the words "float switch" alone.

Also avoid selecting the LZ without checking whether it has enough movement inside the tank, ignoring the LA's specific gravity requirement, choosing a switch without checking process temperature and pressure, assuming IP68 and IP65 mean the products can be used interchangeably, and replacing an old side-mounted switch without confirming process connection and insertion depth.

For pump applications, also consider the actual start and stop logic before installation. A switch that operates correctly at the wrong elevation is still the wrong installation.

Do This, Not That

Quick Selection Checklist

Before sending an inquiry for a Baumer float level switch, confirm the liquid, tank or vessel type, side-mounted or suspended installation, high-level or low-level function, operating temperature, operating pressure, liquid specific gravity where applicable, required switching differential, electrical contact requirement, process connection for LA, cable length for LZ and whether the application is alarm duty or automatic pump control.

Providing these details usually makes model selection much faster.

Why Buy Baumer Float Level Switches from Radical TechMart?

A float level switch is inexpensive compared with the pump, vessel or process it protects, but incorrect selection can still create repeated operating problems.

At Radical TechMart, the focus is to help buyers identify whether the application needs a simple cable float such as the Baumer LZ or a process-mounted switch such as the Baumer LA, then confirm the important operating conditions before quotation.

Support can include product selection, datasheet clarification, model configuration, pricing and availability for water treatment companies, OEMs, EPC contractors, process industries, maintenance teams and industrial purchase departments.

Final Thoughts

The best Baumer float level switch is not automatically the model with the higher temperature rating or more options.

For a water tank or sump, the simpler LZ cable float may be exactly what the application needs. For a pressurised process vessel, chemical application or defined side-mounted switching point, the LA can be the more appropriate choice.

The selection becomes straightforward once you answer four questions first: What is the liquid, where will the switch be mounted, what are the temperature and pressure, and exactly what level action should occur?

That is a much better way to select a float level switch than starting with price or model number.

FAQs

1. What is a Baumer float level switch used for?

A Baumer float level switch is used for point level detection such as high-level alarm, low-level alarm, filling control, pump start, pump stop and pump protection.

2. What is the difference between Baumer LA and LZ level switches?

The LZ is a cable float that hangs inside the tank and tilts as the level changes. The LA is a side-mounted process level switch using a float arm and magnetic snap-action switching mechanism.

3. Which Baumer level switch is suitable for a water tank?

For a storage tank or reservoir where a suspended float can move freely, the LZ is specifically identified by Baumer for storage tanks, sewage and water treatment and automatic pump control.

4. Which Baumer float switch is better for high-temperature applications?

The LA offers greater temperature capability. Its standard version is specified up to +180°C, while the Type T high-temperature configuration is listed up to 350°C.

5. Can a Baumer float switch be connected to a PLC?

The products provide switch contacts that can typically be incorporated into industrial control circuits. The final PLC input wiring or interposing relay arrangement should be designed according to the PLC input specification and the switch contact rating.

6. What cable lengths are available for the Baumer LZ?

The datasheet lists 3 metres as standard, with 5, 10 and 20 metre versions. For lengths above 20 metres, Baumer advises consulting the factory.

7. What specific gravity is required for the Baumer LA?

The standard LA datasheet specifies a minimum specific gravity of 0.75.

8. What information should I provide when requesting a Baumer LA level switch?

Baumer's ordering information asks buyers to specify the model number, liquid, specific gravity, operating pressure and operating temperature. Process connection, insertion depth, housing and switch output should also be selected according to the required configuration. 

Low pressure measurement is one of those applications where choosing a pressure gauge only by dial size and connection can cause trouble.

A plant may need to monitor clean air pressure, low pressure draft, a gaseous line or a low viscosity process medium. The pressure may be only a few millibars, so the instrument has to provide useful indication in a range where a conventional high pressure gauge would not be the logical choice.

This is where a Baumer Capsule Pressure Gauge fits.

The Baumer capsule gauge range in the supplied datasheets is designed around low pressure measurement, with available ranges from 25 mbar to 600 mbar, pressure, vacuum and compound scale possibilities, several mounting styles and two useful construction choices: the AX SS Case Brass Pressure Gauge and the AF All SS Pressure Gauge.

The important part is deciding which construction is right for your process. The AX and AF may look similar from the front, but the materials, temperature capability, ingress protection and overpressure capability are not the same.

What is a Capsule Pressure Gauge?

A capsule pressure gauge is intended for measuring relatively low pressures where a more sensitive measuring element is required.

In general engineering terms, the pressure acts on a capsule sensing element. Small movement of this element is transferred through the mechanical movement to the pointer, giving a direct local reading on the dial.

For the Baumer models covered here, there is no electrical output specified in the supplied datasheets. These are mechanical indicating instruments intended for local pressure indication.

That distinction matters. If your requirement is only to see the pressure locally at a duct, vessel, utility line or process point, a capsule gauge may be suitable. If you need the pressure value inside a PLC, SCADA, BMS or remote control system, you would normally need an appropriate pressure transmitter or electronic measurement solution as well.

Why Capsule Gauges Matter in Actual Plant Conditions

When pressure is low, range selection becomes especially important.

Suppose the normal process pressure is around 150 mmWC. Installing a gauge designed for much higher pressure may technically give a reading, but the useful movement of the pointer can become too small for practical monitoring.

A properly selected capsule gauge gives the operator a scale that is actually useful for the process.

Baumer lists these gauges for applications including:

• Low pressure draft measurement
• Food and beverage plants
• Pharmaceutical applications
• Breweries
• Conventional power plants
• Nuclear power plants
• Clean air
• Gaseous media
• Low viscosity, non corrosive media that will not obstruct the pressure system

The datasheets specify ±1.6% of full scale accuracy for both AX and AF models.

For a maintenance engineer, this means the first question should not be "Which pressure gauge is cheapest?" It should be "What is the actual operating pressure, what media touches the instrument and what range gives me a useful reading?"

Baumer Capsule Pressure Gauge Range

The uploaded datasheets give two main constructions worth comparing.

Baumer AX Capsule Pressure Gauge

The Baumer AX is an SS case pressure gauge with copper alloy pressure components. It is a practical option where the process medium is compatible with copper alloy wetted parts and the application does not require an all stainless steel pressure system.

It also comes in four dial sizes, making it possible to choose a compact local gauge or a larger dial for easier reading from a distance.

Technical points to note:

• Available range: 25 mbar to 600 mbar
• Accuracy: ±1.6% of full scale
• Nominal sizes: 63, 100, 125 and 150 mm
• Case and bezel: AISI 304 stainless steel, bayonet type
• Capsule: copper alloy
• Socket: copper alloy
• Movement: copper alloy
• Joints: tin soldering
• Protection: IP55
• Ambient temperature: minus 25°C to plus 65°C
• Maximum process temperature: 100°C
• Recommended operating pressure: 75% of scale value
• Overpressure: listed as not suitable
• Zero adjustment provision
• General standard reference: EN 837-3

Where it is commonly suited:

• Low pressure air lines
• Draft measurement
• Clean gas service
• Utility monitoring
• HVAC related low pressure points
• Suitable brewery and food process utilities
• General plant low pressure monitoring

Baumer AF All Stainless Steel Capsule Pressure Gauge

The Baumer AF is the better option when stainless steel wetted parts, a higher process temperature limit or stronger ingress protection are required.

Its maximum listed process temperature is 150°C, compared with 100°C for the AX.

Technical points to note:

• Available range: 25 mbar to 600 mbar
• Accuracy: ±1.6% of full scale
• Nominal sizes: 63, 100, 125 and 150 mm
• Case and bezel: AISI 304 stainless steel
• Capsule: AISI 316 stainless steel
• Socket: AISI 316L stainless steel
• Movement: AISI 304 stainless steel
• Joints: TIG argon arc welding
• Protection: IP65, with IP55 for the 63 mm size
• Ambient temperature: minus 25°C to plus 65°C
• Maximum process temperature: 150°C
• Recommended operating pressure: 75% of scale value
• Overpressure: 130% of maximum scale value
• Zero adjustment provision
• General standard reference: EN 837-3

Where it is commonly suited:

• Pharmaceutical utility applications
• Food and beverage processing
• Breweries
• Clean air systems
• Suitable gas applications
• Process plant low pressure monitoring
• Applications requiring stainless steel wetted components

Baumer AX vs AF Capsule Pressure Gauge

The practical decision is straightforward. If the process is compatible with copper alloy components and the environmental conditions fit the AX specifications, AX may be sufficient. If stainless steel wetted parts, higher process temperature capability or better enclosure protection are important, AF becomes the stronger choice.

Pressure, Vacuum and Compound Ranges

Range selection deserves more attention than most buyers give it.

The Baumer datasheets show pressure scales such as:

• 0 to 250 mmWC
• 0 to 400 mmWC
• 0 to 600 mmWC
• 0 to 1000 mmWC
• 0 to 1600 mmWC
• 0 to 2000 mmWC
• 0 to 2500 mmWC
• 0 to 4000 mmWC
• 0 to 6000 mmWC

Vacuum and compound ranges are also listed.

Baumer notes that other national and international scales such as mbar, kPa, inWC, MWC, inHg and mmHg, along with dual or equivalent scales, can be provided according to requirement.

The selection lesson is important: do not choose the largest available range "for safety." A range that is unnecessarily high makes a low pressure process harder to read.

Mounting Options Matter More Than They Look

A replacement gauge can have the correct pressure range and still be wrong for the installation if the connection and mounting arrangement do not match.

The Baumer capsule range includes several configurations, depending on nominal size:

• Wall, surface or projection mounting with bottom entry
• Direct bottom entry
• Direct lower back entry
• Direct center back entry
• Lower back entry with front flange
• Lower back entry with mounting bracket
• Center back entry with mounting bracket

The dimensional drawings on pages 2 and 3 of the AX and AF datasheets show that the body depth, flange arrangement and mounting dimensions change with nominal size and mounting type. That is particularly important when replacing a gauge in an existing panel or machine.

Before ordering a replacement, check the old gauge from the side and rear, not just from the front.

Process Connections

The ordering tables provide connection options including:

• 1/4 inch BSP male
• 1/4 inch NPT male
• 3/8 inch BSP male
• 3/8 inch NPT male
• 1/2 inch BSP male
• 1/2 inch NPT male
• M20 x 1.5 male

The datasheets also note that other connection types can be provided on request, and that some connections for the 63 mm size are achieved through adaptors.

This is one of the easiest purchasing mistakes to avoid. Confirm the thread before placing the order.

Key Selection Factors for a Baumer Capsule Pressure Gauge

1. Actual working pressure

Start with the normal operating pressure, not only the maximum possible pressure. Both datasheets specify operating pressure at 75% of scale value.

2. Media compatibility

For AX, check compatibility with the copper alloy capsule and socket.

For AF, check compatibility with the AISI 316 capsule and AISI 316L socket.

3. Overpressure possibility

This is a major difference between the two models. AX is listed as not suitable for overpressure, while AF specifies 130% of maximum scale value.

4. Process temperature

AX has a maximum process temperature of 100°C.

AF extends this to 150°C.

5. Ambient condition and enclosure

Both models list an ambient range from minus 25°C to plus 65°C. For protection, AX is IP55, while AF is IP65 for the larger sizes and IP55 for 63 mm.

6. Dial size

Choose 63 mm where space is tight. Consider 100, 125 or 150 mm where the operator needs to read the gauge from farther away.

7. Mounting and connection

Confirm bottom entry, back entry, panel arrangement, flange or bracket requirement before ordering.

8. Required scale

Confirm whether your plant standard uses mbar, mmWC, kPa, inWC or another unit. Dual scales can also be requested according to the datasheet.

Common Mistakes to Avoid

Do This, Not That

Quick Selection Checklist

Before asking for a Baumer Capsule Pressure Gauge quotation, confirm:

1. Normal operating pressure
2. Required pressure, vacuum or compound range
3. Preferred engineering unit
4. Process media
5. Maximum process temperature
6. Possibility of pressure spikes or overpressure
7. Required dial size
8. Bottom or back connection
9. Mounting flange or bracket requirement
10. BSP, NPT or metric process connection
11. Required IP protection
12. Whether copper alloy or stainless steel wetted parts are acceptable
13. Calibration certificate requirement
14. Any custom dial or tag requirement

Optional Features Worth Confirming

The Baumer ordering tables also list options such as calibration certificates, traceable calibration certificates, plexiglass, safety glass, toughened glass, custom dial marking and stainless steel tag plates.

For the AF version, the datasheet also lists options such as material test certificates and an AISI 316 case and bezel for nominal sizes of 100 mm and above.

These options are worth discussing at quotation stage rather than after the gauge has already arrived.

Why Buy Baumer Capsule Pressure Gauges from Radical TechMart?

A low pressure gauge inquiry often begins with something simple such as "Need 100 mm capsule gauge, 0 to 600 mmWC."

But that is not always enough information to select the correct instrument.

At Radical TechMart, the focus is to help buyers check the application before finalizing the gauge, including pressure range, media, wetted material, dial size, mounting type, process connection and installation condition.

This is particularly useful for OEMs, plant maintenance teams, instrumentation engineers, EPC contractors and purchase departments that need a correct replacement or project specification rather than simply another gauge with a similar dial.

Final Thoughts

A Baumer Capsule Pressure Gauge makes sense when the application involves low pressure measurement and clear local indication.

The real selection decision is not AX versus AF based on price alone. It is about what touches the process, how hot the process can become, whether overpressure can occur, what protection level is required and how the gauge has to fit into the existing installation.

For compatible general service, the AX offers a stainless case with copper alloy pressure components. For applications needing stainless steel wetted parts, higher process temperature capability and stronger protection in larger sizes, the AF provides the more appropriate construction.

In low pressure measurement, choosing the correct range and construction is what makes the gauge useful after installation, not simply choosing a familiar model number.

FAQs

1. What is a Baumer capsule pressure gauge used for?

It is used for low pressure measurement in applications such as draft measurement, clean air, gaseous media and suitable low viscosity, non corrosive process media.

2. What pressure ranges are available for Baumer capsule gauges?

The datasheets state an available range from 25 mbar to 600 mbar. Example mmWC pressure, vacuum and compound ranges are also provided.

3. What is the difference between Baumer AX and AF capsule gauges?

AX uses a stainless steel case with copper alloy capsule and socket. AF uses an AISI 316 stainless steel capsule and AISI 316L socket, provides a higher listed process temperature and has IP65 protection for 100 mm and larger versions.

4. Is the Baumer AX suitable for pressure spikes?

The AX datasheet lists its overpressure limit as "Not Suitable." If pressure spikes are expected, this must be considered during selection.

5. What is the accuracy of Baumer capsule pressure gauges?

Both AX and AF datasheets specify accuracy of ±1.6% of full scale.

6. Which dial sizes are available?

Both models are available in standard nominal sizes of 63, 100, 125 and 150 mm.

7. Can I order the gauge in mmWC, mbar or kPa?

Yes. The datasheets reference scales including mbar, kPa, inWC, MWC, inHg and mmHg, along with dual or equivalent scales on request.

8. Can Baumer AX or AF connect directly to a PLC?

The supplied AX and AF datasheets describe mechanical indicating gauges and do not specify an electrical output. For PLC or SCADA pressure monitoring, an appropriate pressure transmitter or electronic pressure instrument should be selected separately.

The quickest way to select the wrong pressure gauge is to ask only two questions:

“What range do you need?” and “What connection size do you need?”

Those details matter, but they are only part of the selection.

A gauge installed on an FRL unit does not face the same conditions as one mounted beside a vibrating compressor. A gauge used on an HVAC water line has different priorities from one installed on hydraulic equipment. And a low cost gauge that works perfectly on a clean air line may be a poor choice where moisture, vibration or higher process temperature is present.

That is where Baumer Utility Pressure Gauges make sense. The range is intended for practical pressure indication across general industrial and utility applications, with multiple dial sizes, case constructions and application focused variants. Baumer's current utility selector covers dial sizes from 40 mm to 250 mm and pressure ranges reaching 400 bar, depending on the selected model.

The important part is not buying the most expensive gauge. It is choosing the construction that actually matches the installation.

What Is a Utility Pressure Gauge?

A utility pressure gauge is a mechanical pressure indicator intended for routine local pressure monitoring on equipment such as pumps, compressors, pneumatic lines, HVAC systems, water systems and industrial machinery.

Most gauges in this Baumer category use the Bourdon tube principle. Pressure entering the gauge causes the curved sensing tube to deform slightly. That mechanical movement is transferred through the internal movement to the pointer, giving a local pressure reading without an electrical power supply.

This independence from power is one reason mechanical gauges remain useful even in highly automated plants. A PLC may receive pressure from a transmitter, but technicians still appreciate being able to look at a pump or air line and immediately see the local pressure.

Why Utility Gauge Selection Matters in Actual Plant Conditions

Pressure gauge problems are often blamed on the gauge after installation, even when the original issue was selection.

For example, a dry gauge may be perfectly suitable on a stable water line. Put the same type beside a compressor with continuous pulsation and the pointer can become difficult to read. Likewise, choosing a very small dial may save space, but it may be uncomfortable to read when the operator stands several metres away.

Before selecting a utility gauge, think about:

• What media will touch the sensing element?
• Is the pressure stable or pulsating?
• Is vibration present?
• What is the normal operating pressure?
• How large should the dial be for comfortable reading?
• Is the installation indoors, outdoors or inside equipment?
• Does the gauge need bottom entry or back entry?
• Is a dry, fillable or liquid filled construction more appropriate?
• What process temperature will reach the gauge?

Answering these questions usually narrows the choice much faster than comparing model numbers alone.

Baumer Utility Pressure Gauge Options

Baumer AAB Utility Pressure Gauge, 40 mm

The AAB is a compact option for installations where panel space or equipment space is limited. Baumer's selector lists AAB as a 40 mm utility pressure gauge with copper alloy wetted material, Class 2.5 accuracy and a measuring range selection extending up to 250 bar depending on configuration.

Technical points to note:

• 40 mm nominal size for AAB
• Accuracy class 2.5
• Copper alloy wetted construction
• Ambient temperature from minus 20°C to plus 65°C
• Process temperature up to 150°C
• Multiple BSP, NPT and BSPT connection possibilities within the AA family
• Pressure, vacuum and selected dual scales are available depending on size and configuration

Where it fits well:

• FRL units
• Pneumatic machines
• Small compressors
• Air lines
• Irrigation equipment
• Compact OEM equipment

Baumer AAH Utility Pressure Gauge, 150 mm

AAH belongs to the same AA utility family, but the larger 150 mm dial changes where it makes sense. Baumer currently lists AAH with copper alloy wetted material, Class 1.6 accuracy and ranges extending up to 400 bar depending on the selected scale.

Technical points to note:

• 150 mm nominal size for AAH
• Accuracy class 1.6
• Copper alloy sensing system
• Process temperature up to 150°C
• Operating pressure recommended at 75% of scale value
• Multiple pressure, vacuum and compound scale options
• Gauge cock, snubber and siphon accessories are referenced in the family datasheet

Where it fits well:

• Utility piping
• Pump stations
• Hydraulic power units
• Water systems
• Large machinery
• Plant services

Baumer ATC SS Case Brass Pressure Gauge, 50 mm

The AT family is a useful step up when the installation needs a stainless steel case and a more rugged construction while retaining copper alloy pressure sensing components.

Baumer's current utility selector lists the ATC variant with a 50 mm dial, copper alloy wetted material, Class 2.5 accuracy and measuring ranges up to approximately 280 bar for this specific size.

Technical points to note:

• ATC nominal size: 50 mm
• Accuracy class 2.5 for the 50 mm size
• AISI 304 stainless steel case
• Copper alloy Bourdon tube and socket
• IP65 protection in the standard family specification
• Dry, fillable or glycerine filled options
• General compliance reference to EN 837 1
• Process temperature up to 150°C for the standard dry version

Where it is commonly used:

• Compressors
• Pumps
• Hydraulic systems
• Pneumatic equipment
• Diesel engines
• Oil and water systems

Baumer AVF HVAC SS Pressure Gauge, 100 mm

The AVF is one of the more application specific products in this group. It is a 100 mm compact case pressure gauge developed around HVAC and clean utility type applications.

Baumer's utility selector lists AVF as a 100 mm gauge with stainless steel wetted material, Class 1.6 accuracy and measuring ranges up to 400 bar depending on configuration.

Technical points to note:

• 100 mm nominal size
• Accuracy ±1.6% FS
• AISI 304 stainless steel case and bezel
• AISI 316L stainless steel Bourdon tube
• AISI 316 stainless steel socket
• IP65 protection
• Standard process temperature up to 180°C
• Dry fillable and glycerine filled options
• Bottom, back and panel mounting arrangements are available within the family

Where it is commonly used:

• Chilled water systems
• HVAC utility piping
• Air handling systems
• Pump skids
• Building services
• Clean utility lines

Baumer BVF ECO SS Pressure Gauge, 100 mm

The BVF is a 100 mm version of Baumer's ECO stainless steel pressure gauge family. It is aimed at buyers who want stainless steel construction without moving into a more elaborate process gauge design.

The current utility selector lists BVF at 100 mm, Class 1.6, with stainless steel wetted material and ranges from approximately 4 to 70 bar.

Technical points to note:

• 100 mm nominal size
• Accuracy ±1.6% FS
• AISI 304 stainless steel case and ring
• AISI 316L stainless steel Bourdon tube
• Welded socket and case construction
• IP65 protection
• Maximum process temperature 200°C
• Pressure, vacuum and compound ranges available within the published range table

Where it is commonly used:

• Clean air systems
• Utility gas lines
• Water services
• Equipment skids
• General plant utilities
• OEM installations

Baumer BVH ECO SS Pressure Gauge, 150 mm

BVH uses the same ECO pressure gauge construction but increases the nominal dial to 150 mm. Baumer currently lists it as Class 1.6 with stainless steel wetted material and a 4 to 70 bar measuring range selection.

Quick Product Selection Guide

The final model still needs to be checked against pressure range, media, connection, mounting and process temperature.

How to Select the Right Utility Pressure Gauge

1. Start With the Normal Operating Pressure

Do not size a gauge so that normal operation sits continuously at the very end of the scale. The AA, AT, AV and BV datasheets generally specify operation around 75% of the scale value, with overpressure capability depending on model and range.

In practice, the operator should be able to see both normal operating pressure and abnormal movement clearly.

2. Match Wetted Material to the Media

For clean air and water, copper alloy gauges may be perfectly adequate. For applications where stainless steel wetted parts are preferred, AV or BV type construction may make more sense.

Selecting stainless steel simply because it sounds better can increase cost without improving the application. Selecting copper alloy where the process is chemically incompatible creates a much bigger problem.

3. Think About Vibration Before Choosing Dry or Filled

If the pointer constantly vibrates, readings become difficult and internal wear can increase.

The AT and AV families provide dry, fillable and glycerine filled options, making them useful when equipment vibration or pulsation needs additional damping.

For stable pressure on a quiet line, a dry gauge may still be the simpler choice.

4. Choose Dial Size for the Person Reading It

A 40 or 50 mm gauge works well directly on compact machinery. A 100 or 150 mm gauge is more comfortable where the reading must be seen from further away.

Do not treat dial size only as a specification. It is an operator visibility decision.

5. Confirm Connection and Mounting

The AA family alone offers bottom entry, back entry, flange mounting and bracket based configurations along with BSP, NPT, BSPT and M20 connection possibilities.

Before ordering, confirm:

• Connection thread
• Connection size
• Bottom or back entry
• Panel mounting requirement
• Available clearance
• Existing replacement dimensions

This is especially important when replacing a gauge already installed on a machine.

Common Mistakes to Avoid

• Choosing a gauge only by price
• Selecting the same pressure range as the normal operating pressure
• Ignoring vibration and pulsation
• Assuming all stainless steel gauges have identical wetted materials
• Choosing a small dial where the operator cannot read it comfortably
• Ignoring bottom entry versus back entry
• Using a utility gauge for dirty or crystallising media without checking suitability
• Ordering before confirming BSP, NPT or other connection requirements
• Assuming a glycerine filled gauge has the same temperature limits as the dry version
• Replacing an old gauge by model number without checking the actual application

Do This, Not That

Quick Selection Checklist

Before requesting a quotation, confirm these points:

1. Normal operating pressure
2. Maximum expected pressure
3. Pressure, vacuum or compound requirement
4. Process media
5. Required dial size
6. Copper alloy or stainless steel wetted parts
7. Dry, fillable or glycerine filled version
8. Bottom entry or back entry
9. BSP, NPT, BSPT or other process connection
10. Process and ambient temperature
11. Vibration or pulsation at the installation point
12. Calibration certificate or special dial requirement

With these details available, pressure gauge selection becomes much faster and the chance of ordering the wrong configuration drops significantly.

Why Buy Baumer Utility Pressure Gauges Through Radical TechMart?

A pressure gauge may look like a simple product, but the number of combinations in range, dial size, mounting, connection, wetted material and filling means there is still plenty of room for selection mistakes.

At Radical TechMart, the focus should not be only on supplying a Baumer pressure gauge. The more useful approach is to understand where the gauge will be installed and then help narrow the configuration based on the actual application.

Whether the requirement is for an FRL unit, HVAC system, pump, compressor, hydraulic system, water line or OEM machine, sharing the application details before purchase can save considerable time during installation.

Final Thoughts

The right utility pressure gauge is not necessarily the most advanced gauge in the catalogue.

For a small pneumatic assembly, a compact economical AA gauge may be exactly what is needed. For machinery exposed to vibration, an AT configuration with filling capability can make more sense. HVAC installations may benefit from the purpose focused AV construction, while the BV family offers an economical stainless steel measuring system for clean utility applications.

The best selection comes from matching range, media, construction, dial size, mounting and operating conditions to the actual installation rather than selecting only by price or model number.

Baumer's current utility portfolio contains 18 listed variants, with nominal sizes from 40 mm to 250 mm and model specific measuring ranges extending up to 400 bar.

FAQs

1. What is a Baumer utility pressure gauge used for?

Baumer utility pressure gauges are used for local mechanical pressure indication in applications such as HVAC, pumps, compressors, water systems, hydraulics, pneumatics, FRL units and general industrial machinery.

2. What is the difference between AA and AT pressure gauges?

The AA is positioned as an economical general purpose gauge with a painted or powder coated steel case and copper alloy measuring system. The AT uses a stainless steel case and is available in dry, fillable and glycerine filled configurations, making it better suited to more rugged equipment installations.

3. Which Baumer utility pressure gauge is suitable for HVAC?

The AV family is specifically identified as an HVAC stainless steel pressure gauge. The AVF variant has a 100 mm dial and Class 1.6 accuracy.

4. When should I use a glycerine filled pressure gauge?

A filled gauge is worth considering where vibration or pressure pulsation makes a dry pointer unstable. AT and AV provide filling options, but the temperature limits of the filled configuration should be checked before selection.

5. Are Baumer utility pressure gauges available with different process connections?

Yes. Depending on family and configuration, the datasheets list BSP, NPT, BSPT and other connection possibilities. Always confirm the exact connection before ordering.

6. What dial size should I choose?

Choose based on available space and viewing distance. Compact 40 mm and 50 mm gauges suit smaller machinery, while 100 mm and 150 mm gauges provide easier local reading in larger installations. Baumer's utility range currently extends from 40 mm to 250 mm.

7. Can utility pressure gauges measure vacuum?

Selected models offer vacuum and compound scales. The exact range depends on gauge family, nominal size and configuration, so the range table should be checked before purchase.

A pressure gauge requirement often starts with three details: pressure range, dial size and process connection.

For a normal utility point, that may get you close. For high pressure gas, hazardous process service or an application where failure consequences matter, it is not enough.

This is where a solid front pressure gauge becomes relevant.

Baumer's current Solid Front Pressure Gauges category contains five models: AIF, AIH, AHG, BTF and BTH. AIF and AIH are stainless steel solid front gauges, AHG uses a fibre glass reinforced polypropylene case with stainless steel wetted parts, while BTF and BTH combine a mechanical pressure indication with a 4 to 20 mA transmitter output.

The important question, therefore, is not simply, “Which Baumer solid front gauge is available?” It is, “Which construction actually fits my process?”

What Makes a Solid Front Pressure Gauge Different?

The safety construction is the main reason to consider this category.

The uploaded Baumer AI datasheet describes a baffle wall positioned between the sensing system and the window, together with a pressure relieving back. The intention is increased safety if the pressure element fails.

Baumer's current AIF technical data identifies this as an S3 safety pattern gauge with solid front and pressure relief back according to EN 837 1. The AHG page also identifies an S3 solid front construction.

In practical terms, this is why a solid front gauge should not be treated as just another dial gauge with a stronger case. Its construction is specifically relevant when the application demands a safety pattern design.

Which Baumer Solid Front Gauge Fits Your Application?

AIF and AIH: All Stainless Steel Solid Front Gauges

AIF and AIH are the logical starting point when you need a conventional mechanical pressure gauge with stainless steel wetted parts and solid front safety construction.

The main difference is dial size. AIF is 100 mm and AIH is 150 mm. Both are currently listed with Class 1 accuracy and measuring ranges from 0 to 0.6 bar through 0 to 1600 bar. AIF carries CE and ATEX approvals on the current selector, while AIH is listed with IBR, CE and ATEX.

The uploaded AI datasheet gives more practical detail. It specifies AISI 316L stainless steel for the Bourdon tube and socket, AISI 304 stainless steel for the standard case, movement and blow off disc, IP65 protection, shatterproof safety glass, and dry, fillable or glycerine filled configurations. It also lists an optional accuracy of ±0.5% of full scale for applicable dry versions.

Best for: Process plants where a stainless steel mechanical gauge, wide pressure range and solid front construction are required.

Why these models make sense: AIF gives you the more compact 100 mm format. AIH gives you a larger 150 mm dial when visibility from a greater distance matters.

The current AIF data also lists maximum media temperature up to 300°C for the unfilled version, with lower limits for filled configurations. This is one specification worth checking carefully when the gauge is installed near hot process lines.

AHG: Polypropylene Case with Stainless Steel Measuring System

AHG is different from the AIF and AIH family.

It uses a 4½ inch fibre glass reinforced polypropylene case, while the process connection and Bourdon tube are stainless steel AISI 316L. Baumer currently specifies ±0.5% accuracy according to ASME B40.100, IP65 protection and gauge, compound and vacuum pressure measurement.

The uploaded AH datasheet also describes the solid front construction with a baffle wall and pressure relieving back, AISI 316L wetted parts and dry fillable or glycerine filled configurations.

Best for: Applications where a polypropylene case is preferred while retaining stainless steel wetted components.

Why this model makes sense: AHG is not simply another size of AI. Its case construction and standard ±0.5% accuracy make it a separate selection option.

It is particularly worth comparing with AIF when you need approximately the same dial size but have different requirements for case material or accuracy.

BTF and BTH: Mechanical Gauge Plus 4 to 20 mA Output

This family solves a different problem.

Sometimes the operator needs a pressure reading at the pipe, but the same value also needs to go back to a PLC, PID controller or data logger. Installing a separate gauge and transmitter is not always the preferred arrangement.

BTF and BTH combine local mechanical indication with a pressure transmitter. BTF uses a 100 mm dial, while BTH uses a 150 mm dial. Both are currently listed for gauge, compound and vacuum measurement, with a 2 wire system, 24 VDC supply, DIN electrical connection and 4 to 20 mA output.

The BT datasheet goes further. It specifies a ceramic transmitter diaphragm, AISI 316L stainless steel process connection, 4 to 20 mA output and transmitter accuracy of ≤ ±0.5% FS using BFSL, while the mechanical pressure gauge section is specified at ±1.0% of full scale. It also identifies pharmaceutical, oil, refrigeration, HVAC and compressor industries as applications.

Best for: Applications requiring both local pressure indication and an analog signal for remote monitoring or control.

Why these models make sense: An operator can see pressure locally while the control system receives the 4 to 20 mA signal.

This is also where buyers need to read the specifications carefully. The mechanical gauge accuracy and transmitter accuracy are not the same specification.

Quick Model Selection

Baumer's current category selector confirms these five products and their basic size, range, material and accuracy differences.

How to Select a Solid Front Pressure Gauge Correctly

1. Start With the Actual Operating Pressure

Do not automatically select a gauge whose full scale value is almost equal to the normal process pressure.

The AI and AH datasheets specify normal operating pressure at 75% of scale value. Their overpressure limits then vary according to the selected range.

That makes pressure headroom an important part of selection.

For example, if your process normally operates close to the maximum indicated value, check whether a higher range would provide a more appropriate operating margin.

2. Check the Process Media Against the Wetted Parts

For AIF and AIH, the standard Bourdon tube and process connection use AISI 316L stainless steel. AHG also uses AISI 316L wetted parts.

BTF uses AISI 316L for the process connection and Bourdon tube, while its transmitter section uses a ceramic diaphragm and NBR sealing.

This distinction matters because choosing by case material alone tells you very little about actual process compatibility.

3. Check Process Temperature Before Choosing Dry or Filled

A filled gauge may be attractive when damping is required, but do not assume the process temperature limit remains identical to the dry version.

For example, Baumer's current AIF page specifies media temperatures up to 300°C when unfilled, 100°C when glycerine filled and 200°C with silicone oil.

The AH product page gives a lower maximum process temperature for its unfilled construction, while the BTF and BTH transmitter gauges are listed for media temperatures from minus 25°C to 80°C.

This is one area where copying the pressure range from an existing gauge without reviewing temperature can create the wrong replacement.

4. Decide Whether Local Indication Is Enough

If the reading is only required at the equipment, an AIF, AIH or AHG may be sufficient.

If the same pressure value must also reach a control panel, PLC, PID controller or logger, BTF or BTH deserves closer attention because the BT design provides a 4 to 20 mA transmitter alongside the dial indication.

Do not purchase BTF or BTH without confirming the 24 VDC supply, 2 wire loop and DIN connector arrangement with your panel design.

5. Choose the Dial Size for the Installation, Not the Catalogue

A 150 mm gauge is easier to read from a distance, but it also occupies more space.

AIF and BTF provide 100 mm options. AIH and BTH provide 150 mm options. AHG sits in between as a 4½ inch design.

Check clearance around piping, valves, manifolds and nearby instruments before finalizing the size.

6. Confirm Mounting and Process Connection

The AI datasheet provides several mounting arrangements, including direct bottom entry and additional mounting options. Standard connection options include ½ inch BSP male and ½ inch NPT male, with M20 × 1.5 and other connections also listed.

The AH datasheet includes wall or surface mounting, direct lower back entry and lower back entry with front flange. One particularly important detail is that the direct lower back entry configuration is identified as never fillable.

That is the type of small ordering detail that can become a large site problem if it is missed.

Common Selection Mistakes

One Source Detail Worth Confirming Before Ordering

There are a few differences between the uploaded April 2025 datasheets and Baumer's current web data.

For example, the AI datasheet lists a standard ambient temperature of minus 20°C to +65°C, while the current AIF web page lists minus 25°C to +65°C.

The AH PDF shows pressure ranges beginning at 0/0.6 bar, while the current AHG web page displays its minimum range as 0 to 0.6 mbar.

Because these sources do not fully agree, confirm the latest model datasheet and ordering code before final purchase, especially for the lowest pressure range and temperature limits.

Quick Selection Checklist

Before sending an inquiry for a Baumer solid front pressure gauge, confirm:

1. Gauge, vacuum or compound pressure requirement
2. Normal operating pressure
3. Maximum expected pressure
4. Process media
5. Process temperature
6. Required accuracy
7. 100 mm, 150 mm or 4½ inch dial
8. Dry, fillable or liquid filled construction
9. Bottom, back or other mounting requirement
10. BSP, NPT, M20 or other process connection
11. Required material of wetted parts
12. IP and approval requirements
13. Whether only local indication is needed
14. Whether 4 to 20 mA output is required
15. Calibration or material certificates required

Why Buy Baumer Solid Front Pressure Gauges from Radical TechMart?

A pressure gauge inquiry should not stop at “0 to 100 bar, ½ inch connection.”

The correct selection also depends on media, operating pressure, temperature, mounting, dial size, material, accuracy, fill requirement and whether the pressure value must stay local or be transmitted to a control system.

At Radical TechMart, the focus is to help industrial buyers compare these application details before finalizing the instrument.

Whether the requirement is an AIF or AIH mechanical solid front gauge, an AHG polypropylene case gauge, or a BTF or BTH gauge with 4 to 20 mA transmission, the selection should start with the process conditions.

Final Thoughts

The biggest advantage of the Baumer solid front pressure gauge range is not that it gives you five model numbers to choose from. It gives you different constructions for different types of pressure measurement jobs.

Choose AIF or AIH when you need an all stainless steel mechanical safety pattern gauge. Consider AHG when its polypropylene case construction and ±0.5% accuracy fit the application. Look at BTF or BTH when the requirement includes both a local dial and a 4 to 20 mA signal.

In industrial pressure measurement, the correct gauge is selected by understanding what happens at the process connection, not simply by matching the dial range printed on the old instrument.

FAQs

1. What is a Baumer solid front pressure gauge?

It is a safety pattern pressure gauge with a solid barrier between the sensing system and viewing side, together with pressure relief construction. Baumer identifies AIF and AHG as S3 safety pattern gauges.

2. What is the difference between AIF and AIH?

The main model distinction is nominal size. AIF is 100 mm and AIH is 150 mm. Both are listed as stainless steel solid front gauges with Class 1 accuracy and measuring ranges up to 1600 bar.

3. What is the difference between AIF and AHG?

AIF uses a stainless steel case and has Class 1 accuracy. AHG uses a fibre glass reinforced polypropylene case and is listed at ±0.5% accuracy according to ASME B40.100. Both use stainless steel wetted parts.

4. Which Baumer pressure gauge provides 4 to 20 mA output?

BTF and BTH provide local pressure indication together with a 2 wire 4 to 20 mA transmitter operating from 24 VDC. BTF is 100 mm and BTH is 150 mm.

5. Can Baumer solid front gauges measure vacuum and compound pressure?

Yes. The AI, AH and BT families include gauge, compound and vacuum pressure options, subject to the selected model and range.

6. Can I use a glycerine filled solid front gauge?

Selected AI and AH configurations are available as fillable or glycerine filled versions. Temperature limits and mounting restrictions should be checked before ordering.

7. Which model should I select for PLC pressure monitoring?

If both local indication and a standard analog pressure signal are required, BTF or BTH are the relevant models in this category because they provide 4 to 20 mA output.

A pressure gauge is one of the simplest instruments in a plant, but it is also one of the easiest to select incorrectly.

A maintenance team may ask for a 0 to 10 bar gauge with a bottom connection. That sounds complete, but it still leaves several important questions unanswered. What is the process media? Is the line vibrating? What process temperature will the gauge see? Is the pressure only a few hundred millibar? How far away will the operator read the dial?

These details decide whether you need a compact stainless steel Bourdon gauge, a larger industrial gauge for easier reading, or a capsule gauge specifically meant for low-pressure measurement.

Baumer offers different pressure gauge constructions for these requirements. The ADC and ADD models use an all stainless steel Bourdon measuring system, while the AXD, AXF and AXH models use a capsule measuring element with copper alloy wetted parts for low-pressure applications.

The right way to select between them is not by model number alone. Start with the application.

What Are Industrial Pressure Gauges?

Industrial pressure gauges provide a direct local indication of pressure at a machine, pipeline or process point.

You will commonly find them on:

• Pumps
• Compressors
• Hydraulic systems
• Refrigeration equipment
• Process lines
• Chemical equipment
• Utility skids
• Diesel engines
• Food processing equipment
• Pharmaceutical equipment

Unlike a pressure transmitter, a mechanical pressure gauge does not normally send an electrical signal to a PLC or SCADA system. Its main job is to give operators and maintenance teams an immediate pressure reading directly at the equipment.

This makes the gauge useful for startup checks, troubleshooting, preventive maintenance and routine operator rounds.

Bourdon Pressure Gauge or Capsule Pressure Gauge?

This is the first major selection decision.

Choose a Bourdon gauge when:

You are measuring normal industrial pressure on pumps, compressors, hydraulic systems, process lines or machinery.

Baumer ADC and ADD use a Bourdon measuring system with AISI 316L stainless steel for the socket and Bourdon element. Their standard construction is designed for demanding industrial pressure measurement.

Choose a capsule gauge when:

The pressure is very low and a conventional industrial pressure gauge is not the best fit.

The Baumer AX series is designed for low-pressure measurement. Available pressure ranges start from 25 mbar and extend to 600 mbar. Typical applications include clean air, gases, draft measurement and low-viscosity, non-corrosive media.

That means a pump discharge pressure point and a low-pressure air duct may both need a gauge, but they should not automatically use the same type.

Baumer Industrial Pressure Gauge Models

Baumer ADC All Stainless Steel Pressure Gauge

The Baumer ADC is a practical option when you need a compact pressure gauge for industrial machinery, pumps or equipment where installation space is limited.

Its 50 mm dial keeps the overall size small, while the stainless steel measuring system makes it suitable for industrial pressure applications where material compatibility matters.

The standard 50 mm version has an accuracy of ±2.5% of full scale. If the application requires easier reading or better accuracy, moving to the 63 mm ADD version may make more sense.

Technical points to note:

• Nominal size: 50 mm
• Measuring principle: Bourdon
• Accuracy: ±2.5% of full scale
• Case and bezel: AISI 304 stainless steel
• Socket: AISI 316L stainless steel
• Bourdon element: AISI 316L stainless steel
• Movement: AISI 304 stainless steel
• Standard protection: IP65
• Ambient temperature: -25°C to +65°C
• Standard process temperature: maximum 200°C
• Operating pressure: 75% of scale value

Where it is commonly used:

• Pumps
• Engine compressors
• Diesel engines
• Hydraulic systems
• Refrigeration equipment
• OEM machinery

Baumer ADD All Stainless Steel Pressure Gauge

The Baumer ADD is a better fit when you still want a compact industrial gauge but need a larger 63 mm dial and improved reading accuracy.

In practical maintenance work, the difference between a 50 mm and 63 mm dial can matter. Gauges are often installed below eye level, inside machinery or next to pumps and piping. Better dial visibility makes routine inspection easier.

The model can also be configured as a dry, fillable or glycerine-filled gauge depending on the installation condition.

For machinery with vibration or pressure pulsation, a liquid-filled configuration may improve pointer stability and reduce mechanical wear.

Technical points to note:

• Nominal size: 63 mm
• Measuring principle: Bourdon
• Accuracy: ±1.6% of full scale
• Case and bezel: AISI 304 stainless steel
• Socket and Bourdon: AISI 316L stainless steel
• Standard protection: IP65
• Optional IP66 and IP67 protection listed
• Standard process temperature: maximum 200°C
• Dry, fillable and glycerine-filled configurations available
• Multiple bottom-entry and back-entry mounting arrangements available

Where it is commonly used:

• Process pumps
• Compressor systems
• Hydraulic equipment
• Petrochemical plants
• Pharmaceutical equipment
• Food and beverage processes

Baumer AXD Capsule Pressure Gauge

The Baumer AXD is intended for applications where pressure is too low for the normal selection logic used with a Bourdon gauge.

With a 63 mm nominal size and capsule measuring element, it is well suited to compact low-pressure indication points.

Technical points to note:

• Nominal size: 63 mm
• Measuring principle: Capsule
• Accuracy: ±1.6% of full scale
• Case and bezel: AISI 304 stainless steel
• Capsule: Copper alloy
• Socket: Copper alloy
• Movement: Copper alloy
• Standard protection: IP55
• Ambient temperature: -25°C to +65°C
• Process temperature: maximum 100°C
• Operating pressure: 75% of scale value
• Zero adjustment provision

Where it is commonly used:

• Clean air pressure measurement
• Gas pressure indication
• Draft measurement
• Food processing equipment
• Pharmaceutical utilities
• Low-pressure process systems

Baumer AXF Capsule Pressure Gauge

AXF uses the same basic capsule pressure measuring concept as the AXD but increases the dial size to 100 mm.

That larger dial becomes useful when the pressure point is mounted farther away from the operator or when small pressure changes need to be read more comfortably.

The AX series supports multiple pressure, vacuum and compound scales, including units such as mbar, kPa, inWC, MWC, inHg and mmHg depending on the requirement.

Technical points to note:

• Nominal size: 100 mm
• Capsule measuring element
• Accuracy: ±1.6% of full scale
• AISI 304 stainless steel case
• Copper alloy capsule and socket
• IP55 protection
• Zero adjustment provision
• Maximum process temperature: 100°C
• Multiple bottom-entry, back-entry and flange mounting arrangements available

Where it is commonly used:

• Low-pressure utility systems
• Clean air lines
• Gas pressure monitoring
• Draft indication
• Food and beverage plants
• Pharmaceutical utilities

Baumer AXH Capsule Pressure Gauge

The Baumer AXH takes the same low-pressure capsule concept into a 150 mm nominal-size gauge.

This is useful when local pressure needs to be visible from a greater distance or when operators need a large, easy-to-read dial.

AXH retains the low-pressure capsule design, copper alloy measuring system and ±1.6% full-scale accuracy of the AX family.

Technical points to note:

• Nominal size: 150 mm
• Measuring principle: Capsule
• Accuracy: ±1.6% of full scale
• Stainless steel case and ring
• Copper alloy capsule
• Copper alloy socket
• IP55 protection
• Maximum process temperature: 100°C
• Zero adjustment provision
• Multiple mounting configurations available

Where it is commonly used:

• Plant utility systems
• Large process equipment
• Clean gas lines
• Draft measurement
• Low-pressure monitoring stations
• Applications requiring easy long-distance reading

ADC vs ADD vs AXD vs AXF vs AXH

Key Selection Factors for Industrial Pressure Gauges

1. Start with the actual pressure range

Do not select a gauge whose maximum scale is almost equal to normal operating pressure.

For the AD series, the recommended continuous operating pressure is 75% of the scale value. The gauge also has defined overpressure limits depending on the selected pressure range.

Give the gauge enough headroom for normal process variation.

2. Check whether the pressure is genuinely low

If the requirement is measured in tens or hundreds of millibar, a capsule gauge may be more appropriate than a standard Bourdon gauge.

This is where AXD, AXF and AXH become relevant.

3. Match the wetted material to the media

ADC and ADD use AISI 316L stainless steel for the socket and Bourdon element.

AX models use copper alloy for the capsule and socket.

That difference should be treated as a selection parameter, not just a construction detail.

4. Decide the dial size from viewing distance

A 50 mm dial works well on compact machines.

A 63 mm dial provides a useful balance between size and readability.

For low-pressure applications, 100 mm and 150 mm AX variants become useful when the gauge must be read from farther away.

5. Consider vibration and pulsation

A pump or compressor can produce a pointer that continuously fluctuates.

Where required, consider a liquid-filled configuration or suitable accessories such as a snubber. This helps stabilize the pressure indication under pulsating conditions.

6. Confirm process temperature

Do not check only ambient temperature.

The fluid entering the pressure connection can expose the gauge to much higher temperatures. For high-temperature services, accessories such as siphons or cooling elements may also need to be considered.

7. Confirm mounting and connection before ordering

Bottom entry, lower back entry, center back entry, flange mounting and bracket mounting are not interchangeable once the installation is fabricated.

The connection size and thread standard also need to match the process connection.

Common Mistakes to Avoid

Quick Selection Checklist

Before ordering an industrial pressure gauge, confirm:

1. What is the normal operating pressure?
2. What is the maximum possible pressure?
3. Is it pressure, vacuum or compound measurement?
4. Is the application low pressure?
5. What process media touches the gauge?
6. Are stainless steel wetted parts required?
7. What is the process temperature?
8. Is there vibration or pulsation?
9. What dial size can the operator read comfortably?
10. Is bottom or back entry required?
11. What is the thread and connection size?
12. Is a calibration certificate required?
13. Are IP66, IP67 or other protection options needed?
14. Is an accessory such as a snubber, siphon or gauge cock required?

Why Buy Industrial Pressure Gauges from Radical TechMart?

Pressure gauge selection becomes much easier when the inquiry includes the actual process details rather than only a model number.

At Radical TechMart, the focus is to help customers select pressure instruments according to application, measuring range, media, material, mounting and installation condition.

Support is available for OEMs, maintenance teams, factories, EPC contractors, project engineers and purchase departments looking for Baumer pressure gauges and other industrial pressure instruments.

If you are replacing an existing gauge, sharing the old model number, pressure range, connection, dial size and application can help narrow down the suitable replacement much faster.

Final Thoughts

The difference between ADC, ADD, AXD, AXF and AXH is not simply dial size.

ADC and ADD are better suited to conventional industrial pressure measurement using an all stainless steel Bourdon measuring system. AXD, AXF and AXH move into low-pressure measurement using a capsule mechanism, with dial size increasing according to the visibility requirement.

The best pressure gauge is the one that matches the process pressure, media, operating temperature, mounting arrangement and the way the maintenance team will actually use it.

In industrial applications, correct pressure gauge selection saves much more than the cost of replacing a wrong instrument. It makes daily inspection easier, reduces premature failure and gives operators a pressure reading they can actually trust.

FAQs

1. What is the difference between Baumer ADC and ADD pressure gauges?

Both use an all stainless steel Bourdon measuring system. ADC is the 50 mm version with ±2.5% full-scale accuracy, while ADD is the 63 mm version with ±1.6% full-scale accuracy and better dial readability.

2. When should I use a capsule pressure gauge?

A capsule gauge is useful for low-pressure applications such as clean air, gas and draft measurement. The Baumer AX range is designed for low pressures from 25 mbar to 600 mbar.

3. What is the difference between AXD, AXF and AXH?

The main difference is nominal dial size. AXD is 63 mm, AXF is 100 mm and AXH is 150 mm. Larger dial sizes are useful when the gauge needs to be read from farther away.

4. Can Baumer industrial pressure gauges be glycerine filled?

The AD series includes dry, fillable and glycerine-filled configuration options. Liquid filling can be useful where vibration or pulsation affects pointer stability.

5. Can these pressure gauges connect directly to PLC or SCADA?

These are mechanical pressure gauges intended primarily for local pressure indication. For electrical signal transmission to a PLC, HMI or SCADA system, consider a pressure transmitter or an appropriate electronic pressure instrument.

6. How do I choose the correct pressure gauge range?

Select a range that keeps normal operating pressure comfortably below full scale. Also consider startup pressure, process fluctuations and possible pressure spikes before finalizing the range.

7. Is stainless steel construction always necessary?

Not always. It depends on process media, environment and application. However, wetted-part compatibility should always be checked. A stainless steel case alone does not mean the internal measuring parts are stainless steel.

8. What details should I provide when asking for a pressure gauge quotation?

Provide pressure range, media, dial size, process connection, mounting type, process temperature, required accuracy, dry or filled preference and any calibration requirement.

Buy Danfoss Products here

A pressure switch is usually noticed only when something goes wrong: a pump does not cut off, a compressor keeps running, a boiler safety circuit trips, or a hydraulic unit gives unstable operation. In many factories, the mistake is not that a pressure switch was used. The mistake is that the wrong pressure range, reset type, differential, enclosure rating, or process connection was selected.

The Danfoss RT Series Pressure Switch is used in industrial and marine applications where pressure needs to trigger an electrical switching action. The RT range includes pressure switches, differential pressure switches, neutral-zone regulation switches, and safety pressure switches for specific boiler plant applications. Danfoss describes RT pressure switches as pressure-controlled, single-pole changeover switches where contact position depends on pressure at the connection port and the set value.

This guide focuses on commonly used RT pressure switch models available for industrial selection: Danfoss RT 5, RT 110, RT 112, RT 116, RT 121, and RT 200.

Below details are based on the available information. Final specification should be confirmed from the official datasheet before purchase.

What is a Danfoss RT Series Pressure Switch?

A Danfoss RT pressure switch is an electromechanical pressure switch used to make or break an electrical circuit when pressure reaches a set point. In simple words, it converts pressure condition into a switching command.

Typical use cases include:

• Pump ON/OFF control
• Compressor cut-in / cut-out control
• Hydraulic power pack protection
• Lubrication oil pressure monitoring
• Boiler and burner safety interlock
• Vacuum or suction pressure monitoring
• Alarm signalling to control panels
• Marine and industrial equipment protection

Most RT pressure switch models use SPDT contact function, which means the switch can be wired as normally open or normally closed depending on the control logic. For many control panels, this is useful because the same switch can be adapted for alarm, trip, interlock, or start-stop logic.

Why RT Series Selection Matters in Actual Plant Conditions

A pressure switch is not selected only by pressure range. The real selection depends on how the switch will behave when the system pressure rises or falls.

For example, a pump protection application may need automatic reset after pressure normalizes. A high-pressure safety application may require manual reset so the system does not restart without operator checking. A vacuum application needs a negative pressure range, while a compressor application needs a range that covers cut-in and cut-out points with the correct differential.

This is where many buyers make a mistake. They ask for “Danfoss RT pressure switch” but do not confirm:

• Required pressure range
• Cut-in and cut-out pressure
• Adjustable or fixed differential
• Auto reset or manual reset
• Process media
• Process connection
• Enclosure rating
• Electrical load
• Panel wiring logic
• Whether the switch is for control, alarm, or safety

A purchase team may compare price, but the maintenance team will face the result if the switch trips incorrectly or does not reset as expected.

Danfoss RT Series Models Covered

Danfoss RT 5

Danfoss RT 5 is useful when the application requires pressure switching in a higher range compared to low-pressure models. It is often considered where pressure rise must be monitored and a manual maximum reset is preferred so the system does not restart without operator attention.

Technical points to note:

• Regulation range: 4–17 bar
• Differential: 1.2 bar
• Contact function: SPDT
• Reset function: Manual Max
• Pressure connection: G 3/8 male
• Enclosure rating: IP54
• Maximum working pressure: 22 bar
• Confirm exact code and variant before ordering

Where it is commonly used:

• Air compressor systems
• Hydraulic power packs
• Pump discharge pressure monitoring
• Industrial machinery protection
• Utility pressure panels
• High-pressure alarm circuits

Danfoss RT 110

Danfoss RT 110 is suitable for low-pressure applications where the system must not resume operation automatically after pressure drops below a set point. This is useful in protection logic where low pressure indicates a fault condition.

Technical points to note:

• Regulation range: 0.2–3 bar
• Differential: 0.08 bar
• Contact function: SPDT
• Reset function: Manual Min
• Pressure connection: G 3/8 male
• Enclosure rating: IP54
• Maximum working pressure: 7 bar
• Useful where low-pressure fault must be manually acknowledged

Where it is commonly used:

• Lubrication oil pressure protection
• Low-pressure pump circuits
• Burner or boiler auxiliary systems
• Compressor auxiliary pressure monitoring
• Industrial safety interlocks
• Control panel alarm circuits

Danfoss RT 112

Danfoss RT 112 is better suited when the pressure range is low and automatic reset is acceptable. It is practical for low-pressure control or alarm applications where the switch should return to normal after pressure recovers.

Technical points to note:

• Regulation range: 0.1–1.1 bar
• Differential: 0.07–0.16 bar
• Contact function: SPDT
• Reset function: Auto
• Pressure connection: G 3/8 male
• Enclosure rating: IP66
• Maximum working pressure: 7 bar
• Better suited where pressure recovery can automatically restore the contact condition

Where it is commonly used:

• Low-pressure pump systems
• Air or water pressure monitoring
• Utility pressure alarms
• HVAC auxiliary pressure monitoring
• Industrial process panels
• Low-pressure control circuits

Danfoss RT 116

Danfoss RT 116 is a practical medium-pressure switch for applications where the operating set point falls within the 1–10 bar range. It is useful for pump control, compressor auxiliary control, and general industrial pressure monitoring.

Technical points to note:

• Regulation range: 1–10 bar
• Differential: 0.33–1.3 bar
• Contact function: SPDT
• Reset function: Auto
• Pressure connection: G 3/8 male
• Enclosure rating: IP66
• Maximum working pressure: 22 bar
• Suitable for common industrial pressure bands

Where it is commonly used:

• Pump pressure control
• Compressor pressure monitoring
• Hydraulic auxiliary circuits
• Industrial water systems
• Utility pressure panels
• Process equipment pressure alarms

Danfoss RT 121

Danfoss RT 121 is used when the process condition is below atmospheric pressure. This makes it suitable for vacuum or suction-side monitoring where normal positive-pressure switches are not suitable.

Technical points to note:

• Regulation range: -1 to 0 bar
• Differential: 0.09–0.4 bar
• Contact function: SPDT
• Reset function: Auto
• Pressure connection: G 3/8 male
• Enclosure rating: IP66
• Maximum working pressure: 7 bar
• Selected specifically for vacuum / negative pressure conditions

Where it is commonly used:

• Vacuum systems
• Pump suction monitoring
• Filter blockage indication
• Process suction lines
• Packaging machinery vacuum circuits
• Industrial utility vacuum panels

Danfoss RT 200

Danfoss RT 200 is a general-purpose pressure switch for lower-to-medium pressure applications where the range is around 0.2–6 bar. It is commonly considered for pump, air, water, and utility pressure switching.

Technical points to note:

• Regulation range: 0.2–6 bar
• Differential: 0.25–1.2 bar
• Contact function: SPDT
• Reset function: Auto on one common variant
• Pressure connection: G 3/8 male
• Enclosure rating: IP66
• Maximum working pressure: 22 bar
• Confirm exact code, because reset function may vary by product variant

Where it is commonly used:

• Pump control systems
• Water pressure monitoring
• Compressor auxiliary circuits
• Industrial utility panels
• Air pressure control
• Process pressure alarms

Key Selection Factors for Danfoss RT Pressure Switches

1. Pressure Range

The selected pressure switch range should comfortably cover the actual operating set point. Do not select a switch where the set point is at the extreme edge of the scale.

2. Differential

Differential is the gap between switching point and reset point. Too small a differential may cause frequent switching. Too large a differential may delay response.

3. Reset Type

Auto reset is useful for normal control. Manual reset is better for safety or fault conditions where operator inspection is required.

4. Contact Function

Most models listed here use SPDT contact logic, useful for panel wiring as NO or NC depending on alarm or control requirement.

5. Enclosure Rating

IP66 is better for harsh, dusty, humid, or outdoor-type locations than IP54, but exact site conditions should always be checked.

6. Process Connection

The listed models commonly use G 3/8 male connection, but confirm whether your installation needs an adapter, isolation valve, siphon, snubber, or gauge cock.

7. Media Compatibility

Confirm whether the switch is being used with air, water, oil, steam, refrigerant, or another process media. Media temperature and compatibility must match the datasheet.

8. Electrical Load

Check whether the switch is switching a relay/contactor coil, PLC digital input, alarm circuit, or direct load. Use interposing relays where needed.

Common Applications

Danfoss RT Series pressure switches are commonly used in:

• Air compressors
• Industrial pumps
• Hydraulic power packs
• Boiler and burner systems
• Marine machinery
• HVAC and utility systems
• Lubrication oil pressure monitoring
• Water treatment systems
• Process pressure alarms
• OEM machine panels
• Control and safety interlock panels

Common Mistakes to Avoid

Do This, Not That

Quick Selection Checklist

1. Confirm whether the application is pressure, vacuum, or differential pressure.
2. Note the normal operating pressure, alarm point, cut-in, and cut-out pressure.
3. Select the correct pressure range with margin.
4. Confirm required differential.
5. Decide whether auto reset or manual reset is required.
6. Check SPDT wiring logic for PLC, relay, contactor, or alarm panel.
7. Verify process connection and adapter requirement.
8. Confirm IP rating and installation environment.
9. Check media compatibility and temperature condition.
10. Confirm exact Danfoss product code and datasheet before ordering.

Specifications to Confirm Before Purchase

Before buying any Danfoss RT Series pressure switch, confirm:

• Exact model and product code
• Pressure regulation range
• Differential range
• Reset function: auto, manual minimum, or manual maximum
• Contact function and contact rating
• Process connection size and type
• Maximum working pressure
• Maximum test pressure
• Enclosure rating
• Ambient temperature range
• Media temperature range
• Media compatibility
• Electrical cable entry
• Mounting arrangement
• Required approval or certification
• Compatibility with PLC, relay, contactor, alarm, or safety circuit

Why Buy from Radical TechMart?

At Radical TechMart, the focus is not only to supply the product, but to help customers select the right instrument for the right application.

For Danfoss RT Series pressure switches, correct selection matters because the same product family includes different pressure ranges, reset types, enclosure ratings, and application roles. A buyer may ask for Danfoss RT 116 or RT 200, but the final choice should depend on actual process pressure, switching logic, installation environment, and maintenance requirement.

Radical TechMart can support OEMs, factories, system integrators, panel builders, EPC contractors, MRO teams, and process industries with product selection, pricing, availability, datasheet support, and technical inquiry guidance.

Final Thoughts

The Danfoss RT Series is a strong choice for industrial pressure switching, but the right model must be selected by application logic. RT 5, RT 110, RT 112, RT 116, RT 121, and RT 200 are not interchangeable just because they belong to the same series. Each model fits a different pressure band, reset requirement, and control purpose.

In industrial applications, the right pressure switch is not selected only by price or model number. It is selected by understanding the process, the pressure range, the switching logic, the environment, and the final control requirement.

FAQs

1. What is the use of Danfoss RT Series pressure switch?

Danfoss RT Series pressure switches are used to switch an electrical contact when pressure reaches a set value. They are commonly used in pumps, compressors, hydraulic systems, boiler plants, marine systems, and industrial control panels.

2. What is the difference between Danfoss RT 116 and RT 200?

RT 116 is commonly selected for 1–10 bar applications, while RT 200 is commonly selected for 0.2–6 bar applications. Final selection should be based on set pressure, differential, reset type, and exact product code.

3. Which Danfoss RT model is suitable for vacuum applications?

Danfoss RT 121 is suitable for vacuum or negative pressure applications because it has a regulation range of -1 to 0 bar.

4. Can Danfoss RT pressure switches connect to PLC panels?

Yes, RT pressure switches with SPDT contacts can be wired into PLC digital inputs, relay circuits, alarm panels, or contactor control circuits, provided the wiring and electrical rating are suitable for the application.

5. What does manual reset mean in a pressure switch?

Manual reset means the switch will not automatically return to normal after pressure recovers. Operator action is required. This is useful in safety or fault conditions where automatic restart may not be desirable.

6. Is Danfoss RT 5 suitable for high-pressure applications?

RT 5 has a 4–17 bar regulation range and 22 bar maximum working pressure in the listed Danfoss data, making it suitable for higher pressure applications within its rating. Confirm the final datasheet and exact product code before purchase.

7. What should be checked before buying a Danfoss RT pressure switch?

Check pressure range, differential, reset type, contact rating, process connection, IP rating, media compatibility, working pressure, electrical wiring, mounting, and exact product code.

Buy Danfoss Products here
A pressure switch usually gets attention only when a machine stops, a compressor trips, a pump fails to cut off, or a pressure alarm does not operate at the right time.

In many plants, the purchase team searches for a replacement pressure switch by matching only the model number. But in actual plant conditions, that is not enough. The pressure range, differential, reset function, enclosure protection, pressure connection, contact rating, media compatibility, vibration level, and installation location all decide whether the switch will work reliably.

This is where the Danfoss KPS pressure switch range becomes important for industrial applications. The KPS Series is commonly selected for pressure monitoring, alarm, and control duties in compressors, pumps, hydraulic systems, boilers, marine systems, diesel plants, power plants, and factory utilities. Danfoss describes the KPS range as suitable for indoor and outdoor applications, while its industrial pressure switch family is used in alarm and regulation systems across factories, diesel plants, compressors, power stations, and ships.

This guide explains how to choose between Danfoss KPS 43, Danfoss KPS 45, and Danfoss KPS 47 based on actual pressure range and application need.

What is a Danfoss KPS Pressure Switch?

A Danfoss KPS pressure switch is an electromechanical pressure control device used to open or close an electrical contact when system pressure reaches a set point.

In simple words, it converts pressure change into an electrical switching action.

It can be used for:

• Pressure alarm
• Compressor start/stop control
• Pump protection
• Hydraulic pressure monitoring
• Boiler pressure alarm
• Marine pressure control
• Process pressure safety interlock
• Control panel relay logic

Unlike a pressure transmitter, a pressure switch does not continuously send a 4–20 mA or digital pressure signal. Instead, it gives a switching output when pressure crosses the set value. That makes it useful where the requirement is alarm, trip, interlock, or ON/OFF control rather than continuous pressure indication.

Why KPS Pressure Switch Selection Matters in Actual Plant Conditions

A wrong pressure switch can create problems that are not visible during purchase but become serious during commissioning or maintenance.

For example, if a compressor needs switching around 35 bar but the selected pressure switch has a low range, it may not operate correctly. If the differential is too narrow, the compressor may cycle too frequently. If the differential is too wide, the system pressure may fall too much before restart. If the enclosure is not suitable for dusty, wet, or outdoor conditions, the switch may fail early.

The Danfoss KPS 43, KPS 45, and KPS 47 look similar as a product family, but they are not interchangeable for every pressure condition. The major selection difference is the operating pressure range and differential band.

How Does a KPS Pressure Switch Work?

A pressure switch senses pressure through its pressure connection. When the pressure rises above the set value, the internal mechanism changes the electrical contact position. When the pressure falls by the selected differential value, the contact returns to its original state.

For KPS pressure switches other than KPS 31, contacts 1–4 make and contacts 1–2 break when pressure rises above the set range value; the switch changes back when pressure falls to the range value minus the differential.

This makes the switch useful for practical control logic such as:

• High pressure alarm
• Compressor cut-out
• Pump stop at upper pressure
• Hydraulic system pressure supervision
• Boiler pressure safety alarm
• Pressure interlock in control panels

The important point is that the set pressure and differential must be selected according to the actual process requirement, not only by the maximum pressure rating.

Danfoss KPS Series Product Selection

Danfoss KPS 43 Pressure Switch

The Danfoss KPS 43 is suitable when the system pressure falls in the lower-to-medium industrial pressure range. It is useful for applications where the control or alarm point is within a 1 to 10 bar range.

Technical points to note:

The above KPS 43 details are listed by Danfoss for model 060-410566 / KPS43, including 1–10 bar regulation range, 0.7–2.8 bar differential, G 1/4 connection, IP67 enclosure rating, and 120 bar maximum working pressure.

Where it is commonly used:

• Pump pressure control
• Air pressure monitoring
• Utility pressure alarm
• Low-to-medium pressure compressor systems
• Water treatment pressure lines
• OEM machine pressure interlocks

Danfoss KPS 45 Pressure Switch

The Danfoss KPS 45 is suitable when the pressure requirement is higher than the KPS 43 range. It is a good fit for medium-to-high pressure industrial systems where the set point falls between 4 and 40 bar.

Technical points to note:

Danfoss lists the KPS45 with 4–40 bar regulation range, 2.2–11 bar differential, auto reset, G 1/4 pressure connection, IP67 enclosure rating, and 120 bar maximum working pressure.

Where it is commonly used:

• Compressor pressure control
• Hydraulic system pressure monitoring
• Pump discharge pressure control
• Industrial process pressure alarm
• Power plant auxiliary systems
• Marine and diesel plant applications

Danfoss KPS 47 Pressure Switch

The Danfoss KPS 47 is suitable for higher pressure industrial applications where the set point is between 6 and 60 bar. It is better suited when the pressure level is beyond the comfort zone of KPS 43 and KPS 45.

Technical points to note:

Danfoss lists the KPS47 with 6–60 bar regulation range, 3.5–17 bar differential, auto reset, G 1/4 pressure connection, IP67 enclosure rating, and 120 bar maximum working pressure.

Where it is commonly used:

• High-pressure compressor protection
• Hydraulic power packs
• Power plant pressure systems
• Marine pressure applications
• Industrial safety interlock panels
• Heavy-duty pump and pressure systems

Quick Comparison: Danfoss KPS 43 vs KPS 45 vs KPS 47

Key Selection Factors for Danfoss KPS Pressure Switches

1. Pressure Range

First confirm the actual working pressure, alarm pressure, cut-in pressure, and cut-out pressure. Do not select the switch only by maximum pressure. The set point should fall comfortably inside the regulation range.

2. Differential

Differential is the gap between switching point and reset point. If differential is too small, the switch may chatter or cycle frequently. If it is too large, the system may operate over an undesirable pressure band.

3. Media Compatibility

Confirm whether the switch will be used with air, gas, oil, water, hydraulic fluid, or another process medium. Always check media compatibility with the official datasheet before purchase.

4. Pressure Connection

The listed models use G 1/4 pressure connection in the Danfoss store data. Confirm whether your installation needs G 1/4, adapter fitting, manifold connection, or a different thread standard before ordering.

5. IP Rating and Installation Area

The listed models show IP67 enclosure rating, which is useful for dusty, wet, or outdoor-like industrial environments. Still, confirm actual installation exposure, cable gland sealing, and panel location before final selection.

6. Contact Rating and Control Circuit

Check whether the pressure switch will directly switch a load, relay, contactor coil, alarm circuit, or PLC digital input. For PLC input use, contact type and wetting current should be confirmed.

7. Vibration and Pulsation

Compressors, pumps, hydraulic systems, and diesel systems may create pulsation. Use proper mounting, snubber, siphon, or isolation accessories if needed.

8. Replacement Fitment

For replacement jobs, match the old model number, pressure range, differential, connection, cable entry, and mounting arrangement. Do not assume all KPS models are direct replacements.

Common Applications

Danfoss KPS Series pressure switches are commonly used in:

• Air compressors
• Hydraulic power packs
• Pump control panels
• Boiler pressure alarm systems
• Marine engine room systems
• Diesel plant utilities
• Power plant auxiliary systems
• Process pressure alarm panels
• Water treatment pressure lines
• OEM machine safety interlocks
• Industrial automation panels
• Factory utility systems

Common Mistakes to Avoid

Do This, Not That

Quick Selection Checklist

Before selecting Danfoss KPS 43, KPS 45, or KPS 47, confirm:

1. Required pressure range
2. Cut-in and cut-out pressure
3. Required differential
4. Media type
5. Maximum working pressure
6. Pressure connection size and thread
7. Electrical contact requirement
8. Cable entry and wiring method
9. Installation environment and IP requirement
10. Datasheet, pricing, availability, and replacement compatibility

Specifications to Confirm Before Purchase

Below details should be confirmed from the official datasheet before final selection:

• Regulation range
• Differential range
• Reset function
• Pressure connection
• Contact function
• Contact rating
• Max. working pressure
• Burst pressure
• Enclosure rating
• Ambient temperature
• Media compatibility
• Cable entry
• Mounting arrangement
• Accessories such as snubber, siphon, adapter, or isolation valve
• Suitability for compressor, pump, hydraulic, boiler, marine, or process application

Specifications may vary depending on exact code and variant. Please confirm the datasheet before final selection.

Why Buy Danfoss KPS Pressure Switches from Radical TechMart?

At Radical TechMart, the focus is not only to supply the product, but to help customers select the right pressure switch for the right application.

For a pressure switch, wrong selection can affect compressor cycling, pump control, alarm reliability, hydraulic safety, and plant uptime. Radical TechMart can support buyers with model comparison, range selection, datasheet support, pricing, availability, and application guidance for industrial pressure control products.

This is especially useful for:

• Maintenance replacement
• OEM panel building
• Compressor panel projects
• Pump automation
• Hydraulic power pack systems
• EPC procurement
• Industrial MRO purchase
• Factory utility upgrades

Final Thoughts

The Danfoss KPS pressure switch should not be selected only by brand or model number. The real selection depends on the pressure range, differential, connection, environment, switching logic, and application.

For lower-to-medium pressure applications, KPS 43 is often the practical choice. For medium-to-high pressure compressor and hydraulic applications, KPS 45 fits better. For higher pressure systems, KPS 47 gives the wider range needed for demanding industrial duty.

In industrial applications, the right pressure switch is selected by understanding the process, the set point, the reset point, the environment, and the final control requirement.

FAQs

1. What is the use of a Danfoss KPS pressure switch?

A Danfoss KPS pressure switch is used for pressure alarm, pressure control, compressor cut-in/cut-out, pump protection, hydraulic pressure monitoring, and industrial safety interlock applications.

2. What is the difference between Danfoss KPS 43, KPS 45, and KPS 47?

The main difference is pressure range. KPS 43 covers 1–10 bar, KPS 45 covers 4–40 bar, and KPS 47 covers 6–60 bar. The differential range also increases from KPS 43 to KPS 47.

3. Which Danfoss KPS pressure switch is suitable for high pressure applications?

For higher pressure applications, Danfoss KPS 47 is usually the model to evaluate because it has a 6–60 bar regulation range and 3.5–17 bar differential range.

4. Can Danfoss KPS pressure switches be used in compressor systems?

Yes, KPS pressure switches are commonly used in compressor pressure control and pressure alarm applications. The correct model depends on compressor operating pressure and required differential.

5. What is differential in a pressure switch?

Differential is the pressure gap between switching action and reset action. It prevents rapid ON/OFF cycling and helps maintain stable pressure control.

6. Is Danfoss KPS suitable for outdoor or dusty industrial areas?

The listed KPS 43, KPS 45, and KPS 47 models show IP67 enclosure rating in Danfoss product data, which supports use in demanding environments. Final suitability should still be checked against the actual installation condition.

7. What should I check before buying a Danfoss KPS pressure switch?

Check pressure range, differential, reset function, pressure connection, media compatibility, contact rating, IP rating, cable entry, and exact datasheet code before purchase.

Buy Danfoss products here
A pressure switch is usually noticed only when something stops working.

A pump does not cut off at the right pressure. A compressor trips too late. A boiler or utility line needs pressure protection. A maintenance engineer checks the panel and finds that the old pressure switch has failed, the differential is wrongly selected, or the pressure range does not match the actual process condition.

This is where the Danfoss KP / KPI Series pressure switches become useful for industrial buyers. They are not just on/off switches. They are control and safety devices used to monitor pressure and operate electrical contacts when the pressure reaches a set value.

For Radical TechMart buyers, the key models in this category are:

• Danfoss KP 35
• Danfoss KP 36
• Danfoss KPI 38 / KP 38

The selection should not be done only by model number. The buyer must confirm pressure range, differential, process connection, contact system, media compatibility, enclosure requirement, reset type, and actual application.

What is a Danfoss KP / KPI Pressure Switch?

A Danfoss KP / KPI pressure switch is an electromechanical device that senses pressure and changes an electrical contact when the set pressure point is reached.

In simple words:

• Pressure increases or decreases in the system.
• The pressure acts on the bellows mechanism inside the switch.
• When the pressure reaches the selected cut-in or cut-out point, the electrical contact changes state.
• This contact can be used for pump control, compressor control, alarm, trip, interlock, or panel indication.

The Danfoss data shows KP / KPI pressure switches use an SPDT contact system, which is useful for control-panel wiring because one common input can be wired to either normally open or normally closed logic depending on the application. The PDF also explains that the snap-action contact function helps reduce contact bounce and supports accurate changeover at the cut-out point.

Why Correct Pressure Switch Selection Matters

In actual plant conditions, wrong pressure switch selection can create repeated downtime.

A low-range switch used in a higher-pressure system may fail early or become unsafe. A high-range switch used in a low-pressure application may not give accurate switching control. A wrong differential can cause short cycling in pumps or compressors. A wrong enclosure can create problems in dusty or wet installations.

For example, if a pump system needs automatic start-stop control, the differential is very important. If the differential is too narrow, the pump may cycle frequently. If it is too wide, pressure may drop more than acceptable before restart.

This is why the buyer should not ask only, “What is the price of Danfoss KP 35?” A better question is:

“Is Danfoss KP 35 suitable for my pressure range, media, switch logic, enclosure condition, and control panel wiring?”

How Danfoss KP / KPI Pressure Switches Work

The pressure switch works through a mechanical pressure-sensing system and electrical switching mechanism.

When process pressure enters the pressure connection, it acts on the bellows. The bellows movement is transferred to a spring and contact mechanism. Once the set pressure is reached, the contact changes over quickly through a snap-action function.

This matters because industrial systems often have vibration, pressure pulsation, motor starting current, and repeated switching cycles. A stable snap-action contact helps the switch operate more reliably than a slow or weak contact movement.

The Danfoss PDF also defines key terms clearly:

• Range setting / set point: pressure range where contact changeover happens.
• Differential: difference between contact changeover on rising and falling pressure.
• Automatic reset: unit restarts automatically after stop.
• Manual reset: unit requires external reset action before operation resumes.
• Permissible operating pressure: highest pressure the unit can be continuously exposed to.

Types of Danfoss KP / KPI Series Products Available

Danfoss KP 35

Danfoss KP 35 is suitable when the application needs low-pressure to medium-pressure control. It is commonly selected for systems where pressure monitoring, pump control, compressor protection, or general industrial pressure switching is required.

Technical points to note:

• Product type: Pressure switch
• Model: Danfoss KP 35
• Setting range: -0.2 to 7.5 bar
• Differential: 0.7 to 4.0 bar
• Permissible operating pressure: 17 bar
• Max. test pressure: 22 bar
• Pressure connection: G 1/4 A
• Contact material options: silver / gold-plated depending on variant
• Variants include IP55 transparent enclosure and stainless steel version options in the PDF listing.

Where it is commonly used:

• Pump control panels
• Compressor control circuits
• HVAC pressure monitoring
• Utility pressure control
• Process equipment pressure interlock
• General industrial automation panels

Danfoss KP 36

Danfoss KP 36 is suitable when the pressure requirement is higher than KP 35. It is often selected for medium-pressure applications where the switch must operate in a stronger pressure range.

Technical points to note:

• Product type: Pressure switch
• Model: Danfoss KP 36
• Setting range: 2.0 to 14.0 bar for common listed variants
• Differential: 0.7 to 4.0 bar
• Additional listed range option: 4.0 to 12.0 bar with 0.5 to 1.6 bar differential
• Permissible operating pressure: 17 bar
• Max. test pressure: 22 bar
• Pressure connection: G 1/4 A
• Contact material options: silver / gold depending on variant
• IP55 transparent enclosure and stainless steel version options are shown for selected variants.

Where it is commonly used:

• Compressor pressure control
• Pump discharge pressure monitoring
• HVAC and refrigeration utility lines
• Industrial skid control panels
• Hydraulic or pneumatic support systems where compatible
• Alarm and trip logic in machine panels

Danfoss KPI 38 

In your store category, KPI 38 can be positioned as the high-pressure option in this KP / KPI product group. It is suitable when the application needs higher pressure switching than KP 35 or KP 36.

Technical points to note:

• Product type: Pressure switch
• Model: Danfoss KPI 38
• Setting range: 8.0 to 28.0 bar
• Differential: 1.8 to 6.0 bar
• Permissible operating pressure: 30 bar
• Max. test pressure: 30 bar
• Pressure connection: G 1/4 A
• Contact material: silver in listed variants
• Listed code numbers include 060-508166 and 060-541866 depending on variant.

Where it is commonly used:

• High-pressure compressor applications
• Pump discharge pressure protection
• Industrial pressure alarm systems
• Process utility pressure monitoring
• Machine safety interlock circuits
• HVAC and refrigeration pressure control where compatible

Quick Comparison: KP 35 vs KP 36 vs KPI 38

Key Selection Factors

1. Pressure Range

First confirm the actual working pressure and required switching pressure.

Do not select the switch at the extreme end of its range if avoidable. A better selection keeps the normal switching point comfortably inside the working range.

2. Differential

Differential controls the gap between cut-in and cut-out.

This matters in pump and compressor applications. Too small a differential may cause frequent cycling. Too large a differential may allow pressure to drop or rise more than the process can tolerate.

3. Reset Type

Automatic reset is useful for normal control. Manual reset is better for safety or fault conditions where the operator must check the system before restarting.

4. Contact Rating

Check the contact rating before connecting the switch directly to a motor starter, relay, contactor, PLC input, alarm circuit, or panel indication. The Danfoss PDF lists SPDT contact systems and contact load data for KP / KPI models.

5. Enclosure Requirement

The PDF mentions IP30 / IP44 / IP55 enclosure possibilities depending on mounting and enclosure arrangement. IP55 requires mounting in a suitable IP55 enclosure.

6. Media Compatibility

Confirm whether the pressure switch is suitable for the actual media: air, water, refrigerant, gas, steam, oil, or other fluid. Do not assume one model suits every media.

7. Process Connection

Confirm G 1/4 A or the required connection thread before ordering. Wrong pressure connection can delay installation and may require unsafe site modification.

Common Applications

Danfoss KP / KPI pressure switches are commonly used in:

• Pump control systems
• Compressor panels
• HVAC systems
• Refrigeration support systems
• Industrial utility lines
• Boiler and pressure monitoring systems
• OEM machines
• Process automation panels
• Alarm and interlock circuits
• Maintenance replacement applications

Common Mistakes to Avoid

Do This, Not That

Quick Selection Checklist

1. Confirm actual working pressure.
2. Confirm required cut-in and cut-out pressure.
3. Select KP 35, KP 36, or KPI 38 based on pressure range.
4. Check differential requirement.
5. Confirm automatic or manual reset.
6. Confirm pressure connection.
7. Check media compatibility.
8. Check contact rating and wiring logic.
9. Confirm enclosure/IP requirement.
10. Verify datasheet, code number, and availability before purchase.

Why Buy Danfoss KP / KPI Pressure Switches from Radical TechMart?

At Radical TechMart, the focus is not only to supply the product, but to help customers select the right pressure switch for the right application.

This matters because a pressure switch is often part of a larger control system. It may connect to a relay, contactor, PLC input, alarm circuit, compressor panel, pump panel, or machine interlock. A wrong selection can create repeated trips, wrong switching, maintenance difficulty, and downtime.

Radical TechMart can support buyers with:

• Danfoss KP / KPI pressure switch selection
• Model comparison between KP 35, KP 36 and KPI 38
• Datasheet and specification checking
• Pricing and availability support
• Replacement selection guidance
• Industrial pressure control product inquiry support

Final Thoughts

The right Danfoss KP / KPI pressure switch is not selected only by price or model number. It is selected by understanding the pressure range, differential, reset logic, contact rating, process connection, enclosure requirement, and actual field application.

For low to medium pressure applications, Danfoss KP 35 may be suitable. For medium-pressure applications, Danfoss KP 36 becomes a stronger option. For higher-pressure switching, Danfoss KPI 38 should be checked.

In industrial applications, the right instrument is not selected only by price or model number. It is selected by understanding the process, the signal, the environment, and the final control requirement.

FAQs

1. What is the difference between Danfoss KP 35 and KP 36?

Danfoss KP 35 is generally used for lower pressure range applications, while KP 36 is selected for higher pressure requirements. KP 35 is listed with a -0.2 to 7.5 bar setting range, while KP 36 is listed with common variants around 2.0 to 14.0 bar.

2. What is Danfoss KPI 38 used for?

Danfoss KPI 38 / KP 38 is suitable for higher-pressure switching applications. It is commonly selected for compressor, pump, high-pressure alarm, cut-out, and control-panel interlock applications.

3. Can Danfoss KP / KPI pressure switches connect to PLC panels?

Yes, they can be wired into PLC, relay, alarm, or control-panel circuits using their electrical contact output. However, contact rating, wiring logic, and electrical load must be confirmed before installation.

4. What does differential mean in a pressure switch?

Differential is the difference between the pressure point where the switch changes state and the pressure point where it resets. It is important for stable pump and compressor operation.

5. Which is better: automatic reset or manual reset?

Automatic reset is suitable for normal control applications. Manual reset is better for safety or fault conditions where the operator must inspect the system before restarting.

6. Is KP 35 suitable for high-pressure applications?

No, KP 35 should not be selected for high-pressure applications beyond its suitable range. For higher pressure, KP 36 or KPI 38 should be checked depending on the actual pressure requirement.

7. What should I confirm before buying a Danfoss KP / KPI pressure switch?

Confirm pressure range, differential, reset type, pressure connection, media compatibility, contact rating, enclosure/IP requirement, code number, and datasheet before purchase.

Types & Selection Guide

In the fast-paced, efficiency-driven world of industrial processes, ensuring accurate pressure measurement isn’t just a best practice — it’s a necessity. One of the most underrated yet mission-critical devices in this realm is the Differential Pressure Gauge (DP Gauge).

Whether you’re a plant engineer, maintenance head, automation engineer, or purchase manager, understanding how to select the right DP gauge can help you avoid costly process failures, unplanned downtime, and safety risks.

This blog will help you understand what a differential pressure gauge is, its various types, and provide you with a practical, step-by-step guide to selecting the right one for your application.

Understanding Differential Pressure Gauges

A Differential Pressure Gauge is designed to measure the difference between two pressure points within a system. Unlike standard gauges that show system pressure, a DP gauge shows the pressure difference between the high-pressure and low-pressure sides.

These gauges are crucial for calculating flow rate based on pressure drop, detecting filter clogging, measuring liquid level in pressurized tanks, and ensuring cleanroom pressure balancing. Without accurate DP measurement, processes can develop blind spots, leading to inefficiencies, equipment damage, or unsafe conditions.

Types of Differential Pressure Gauges

There are different types of differential pressure gauges, each suited for specific applications.

1) Piston-Type Differential Pressure Gauge:

This uses a magnetic piston mechanism to sense differential pressure. It is ideal for clean liquid systems and low differential pressure ranges, typically used in hydraulic circuits, lubrication systems, and filter condition monitoring.

2) Diaphragm-Type Differential Pressure Gauge:

Using dual diaphragms to separate high and low-pressure sides, this type is suitable for both gas and liquid services. It finds applications in HVAC systems, pharmaceutical cleanrooms, and fluid flow monitoring.

3) Bellows-Type Differential Pressure Gauge:

Featuring metal bellows as the sensing element, this gauge is preferred for corrosive media and higher pressure ranges. It is widely used in chemical processes, corrosive gas systems, and energy plants.

4) Digital Differential Pressure Gauge:

Leveraging sensors and microprocessors, these gauges provide electronic readings and are best suited for systems requiring integration with PLC, SCADA, or IoT. Applications include remote monitoring, smart factories, and cleanroom validations.

5) Capsule or Bourdon-Based Differential Pressure Gauge:

Utilizing specialized sensing capsules or bourdon tubes, these are ideal for low-range or niche systems such as laboratory testing, aerospace, and R&D processes.

Step-by-Step Guide to Selecting the Right Differential Pressure Gauge

Choosing the right DP gauge is more than just matching pressure ranges. Below is a practical guide to make the right selection.

1) Know Your Application:

Begin by identifying what you are measuring. Whether it’s filter condition, flow rate across a restriction, liquid level in a pressurized tank, or cleanroom pressure balancing, understanding your goal helps you decide the correct gauge type, response time, and configuration.

2) Identify the Medium:

Determine if the medium is liquid, gas, or steam, and whether it is clean or dirty, corrosive or inert. For industries like pharma and food, diaphragm types with sanitary connections are preferred.

3) Choose the Correct Differential Pressure Range:

Define the expected differential pressure range. For example, 0–1000 Pa for cleanrooms or 0–3 bar for oil filter monitoring. This ensures accuracy and cost-effectiveness.

4) Material of Construction (MOC):

Select materials compatible with your medium. Stainless Steel 316 is suitable for corrosive processes, while anodized aluminum or polycarbonate is ideal for HVAC or cleanroom applications. Bellows-type gauges with SS316 or Monel are preferred for metals and foundry applications.

5) Connection Type and Orientation:

Ensure the gauge has the appropriate connection and mounting type, such as bottom, back, inline, or panel mount, with NPT, BSP, or flange connections. This is critical for easy installation and maintenance, especially for system integrators and panel builders.

6) Output Requirement:

If your system requires output integration, opt for digital DP gauges with 4–20mA, Modbus, IoT integration, or wireless options for remote areas. This feature is essential for project managers in EPC projects who need scalable, data-driven solutions.

7) Accuracy and Resolution:

Choose the appropriate accuracy level for your process. A ±1.6% gauge is sufficient for general use, while ±0.5% or better is required for cleanrooms, pharma, or laboratory processes. High-precision gauges help ensure compliance and process reliability.

Real-World Applications of Differential Pressure Gauges

Differential pressure gauges are extensively used across various industries.

1) Filter Monitoring:

These gauges trigger alarms or initiate cleaning cycles when filter clogging is detected, ensuring system efficiency and preventing breakdowns.

2) Flow Rate Measurement:

In applications using orifice plates and venturi tubes, DP gauges are essential for deriving flow rates from pressure differentials.

3) Cleanroom Monitoring:

Maintaining positive or negative pressure levels in cleanrooms is vital for contamination control, and DP gauges play a crucial role in ensuring this balance.

4) Tank Level Measurement:

In pressurized vessels, DP gauges monitor liquid levels by comparing internal pressure differences, ensuring accurate level measurement without intrusive sensors.

Conclusion

Selecting the right differential pressure gauge is about understanding your process needs, environment, and control systems. From simple piston-type gauges to advanced digital models, each type has its strengths and specific use cases.

By following this guide — and considering your application, media, range, material, connection, and output needs — you can confidently select the right DP gauge for your system.

Our team at Radical TechMart is here to help you choose the best differential pressure gauges for your critical processes. From process industries to cleanrooms, filtration systems to smart factories, we stock a wide range of trusted models to help you measure with precision and confidence.