Selec CH403B Cooling Controller – 2½ Digit LED Display
Selec CH403B Cooling Controller – NTC Based, Defrost + Alarm, 36×72 mm
Compact refrigeration controller with NTC sensor input, ON-OFF control, defrost timer, high/low temperature alarms, door alarm, optional IDM & cyclic timer, and universal 90–270V AC/DC supply. Suitable for chillers, freezers, visi coolers, and cold rooms.
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The Selec CH403B is a feature-rich NTC-based cooling controller designed for commercial refrigeration and cold room applications. It includes ON-OFF temperature control, high/low temperature alarms, a door alarm, defrost management, and selectable °C/°F indication. With optional IDM and cyclic timer functions, it is ideal for high-reliability cooling automation.
Key Features
2½-digit 7-segment LED white display
Capacitive touch keypad
LED indicators for set-point lock, defrost, relay ON, alarm
Defrost management with programmable duration & frequency
High/low temperature alarm, door alarm, sensor break alarm
Door open alarm delay
IDM (optional)
Cyclic timer (optional)
°C/°F selectable
Universal 90–270V AC/DC supply
IP65 protection (front, when panel-mounted)
Technical Specifications
Display Specifications
| Parameter | Value |
|---|---|
| Display | 2½-digit, 7-segment LED white display |
| LED Indications | Set point lock, Defrost, Relay ON, Alarm |
Input Specifications
| Parameter | Value |
|---|---|
| Sensor Type | NTC |
| Temperature Range | –40 to +100°C |
| Nominal Resistance | 10 kΩ @ 25°C |
| Set Point Range | –19.9 to +19.9°C |
| Indication Accuracy | ±1°C |
| Resolution | 0 / 0.1°C |
Functional Specifications
| Parameter | Value |
|---|---|
| Control Action | ON–OFF |
| Hysteresis | 0.1–99.9°C |
| Alarm Modes | High, Low, Door open alarm |
| Display Offset | –19.9 to +19.9°C |
| Reset Time Delay | 0–19.9 min |
| Modes | Heat & Cool |
| Defrost Time | 0–99 min |
| Defrost Frequency | 0–99 (Hr/min/sec) |
| Optional | IDM, Cyclic Timer |
Output Specifications
| Model | Output Ratings |
|---|---|
| CH403B-1-NTC | Relay NO: 10A @ 250VAC / 24VDC |
| CH403B-2-NTC | Relay SPST: 20A @ 250VAC / 30VDC |
| CH403B-3-NTC | Main Relay: 20A @ 250VAC/30VDC; Alarm Relay: 5A/3A @ 277VAC/30VDC |
Auxiliary Supply
| Parameter | Value |
|---|---|
| Voltage | 230 VAC at 50/60 Hz (internally compatible with 90–270 V AC/DC) |
| Power Consumption | 3 VA max |
Environmental Specifications
| Parameter | Value |
|---|---|
| Operating Temp | 0 to 60°C |
| Storage Temp | –20 to 75°C |
| Humidity | 95% RH (non-condensing) |
| Protection | IP65 (front) |
Mechanical Specifications
| Parameter | Value |
|---|---|
| Mounting | Panel |
| Dimensions | 76 × 34.5 × 65.3 mm |
| Panel Cutout | 29 × 71 mm |
| Weight | 150–185 g depending on model |
Applications
Deep freezers
Display refrigerators
Visi coolers
Commercial chillers
Cold rooms
Ice-cream storage freezers
Beverage & dairy coolers
Small HVAC control panels
What’s in the Box?
CH403B Controller
NTC Sensor (TSP04)
Type: NTC
Range: –40 to +100°C
Nominal Resistance: 10kΩ @ 25°C
Mounting hardware
User manual
FAQs
Q1. Is the temperature sensor included?
Yes—the CH403B comes with an NTC TSP04 sensor.
Q2. Does this controller have a defrost function?
Yes—defrost time and frequency are programmable.
Q3. What is the difference between CH403B-1, CH403B-2, and CH403B-3?
1-NTC → 10A relay
2-NTC → 20A relay
3-NTC → 20A main relay + 5A alarm relay
Q4. Does it show temperature in °F?
Yes—°C/°F selectable.
Q5. Is there an alarm feature?
Yes—high/low temp alarm, door alarm, and sensor break alarm.