Rotronic HygroFlex HF73A Heavy Duty Humidity & Temperature Transmitter
Rotronic HF73A Industrial Humidity & Temperature Transmitter – Wall, Duct & Space Versions
Industrial-grade aluminum transmitter with fixed PPS probe, ±1% RH accuracy, dew/frost point output, scalable analog signals, and high-temperature capability up to 200°C.
PRODUCT VERSIONS
HF73A – Wall Version
Same transmitter body as duct model, but without duct probe
Aluminum industrial housing (100 × 100 mm)
Accepts fixed probe extensions (280 / 430 / 580 mm) depending on installation
Best for machinery rooms, industrial walls, chambers
HF73A – Duct Version (Q Version)
Fixed stainless-steel + PPS probe mounted to the housing
Probe lengths: 280 / 430 / 580 mm
Designed specifically for ducts, AHUs & high-temperature airflows
HF73A – “Space Version” (Open Area / Room Monitoring)
Uses same transmitter but with shorter probe (280 mm)
Suitable for open indoor areas, corridors, cleanrooms
Still industrial-grade with aluminum housing
(“Space version” is not a Rotronic marketing term but is supported by probe length + wall mounting.)
Key Features
Measures Humidity, Temperature & Dew/Frost Point
Accuracy at 23°C: ±1.0 %RH / ±0.2 K
High-temperature capability: –100…200°C probe range
(190–200°C allowed max 100 hours)Output signals:
0–1 V, 0–5 V, 0–10 V
0/4–20 mA (3-wire)
Sensor: Hygromer® HT-1
Long-term stability: <1% RH/year
IP65 aluminum housing, UL94-HB fire class
2000-point internal data memory
Sensor diagnostics (drift & state)
Fully scalable analog outputs
HW4 compatible (UART service interface)
Power supply: 15…40 VDC / 12…28 VAC
Technical Specifications
| Parameter | HF73A Wall | HF73A Duct | HF73A Space |
|---|---|---|---|
| Housing | Aluminum | Aluminum | Aluminum |
| Probe Type | Fixed probe | Fixed PPS/SS duct probe | Shorter fixed probe |
| Probe Lengths | 280/430/580 mm | 280/430/580 mm | 280 mm |
| Accuracy | ±1 %RH / 0.2 K | ±1 %RH / 0.2 K | ±1 %RH / 0.2 K |
| Temp Range | –100…200°C probe | –100…200°C probe | –100…200°C probe |
| Outputs | 0–1V, 0–5V, 0–10V, 0/4–20mA | Same | Same |
| IP Rating | IP65 | IP65 | IP65 |
| Power Supply | 15–40 VDC / 12–28 VAC | Same | Same |
| Logging | 2000 points | 2000 points | 2000 points |
| Interface | UART (HW4) | UART (HW4) | UART (HW4) |
Applications
HVAC ducts and AHU systems
High-temperature drying ovens
Food & pharmaceutical production
Industrial climate control
Cleanrooms, controlled areas
What’s Included
HF73A transmitter (wall/duct/space type)
Fixed probe in selected length
Filter carrier (SPA-SS)—filter purchased separately
Mounting hardware
FAQ
Q: Can HF73A measure dew point?
Yes—fully supported and scalable.
Q: Highest probe temperature?
Up to 200°C (limited to 100 hours), continuous 190°C.
Q: Probe lengths available?
280 mm, 430 mm, 580 mm.
Q: Is calibration adjustable?
Yes—1-point or multi-point humidity & temperature adjustment.
Q: Is the housing industrial?
Yes—robust aluminum IP65 housing.