The 22UTH-530M is a Belimo active 24V outdoor humidity and temperature sensor for measuring relative humidity (or absolute humidity / dewpoint / enthalpy — selectable) and temperature in outdoor air. The active humidity output is 4–20 mA (loop output). The temperature output is a PASSIVE NTC 10K Type III (Precon) resistance — your controller must have a matching curve. The white radiated-heat shield protects the sensors from rain AND radiated heat from rooftop and wall surfaces. The curved plate geometry and reflective color promote airflow across the elements, eliminating false high-temperature readings common to outdoor sensors mounted near rooftops or south-facing walls.
Outdoor air humidity and temperature monitoring on rooftop equipment and exterior walls where direct sun exposure or proximity to reflective surfaces would corrupt readings. The radiated heat shield is essential for any sensor mounted on a south or west wall, on a roof above light-colored membrane, or near AC condensers — all sources of radiated heat that bias unshielded sensors several degrees high.
Key Features
Curved white plate shield protects the sensors from rain AND from radiated heat off rooftops, south-facing walls, and AC condenser discharge. For unshielded outdoor sensors near reflective surfaces, radiated heat can bias temperature readings 5-15°F high in summer afternoon conditions — this shield eliminates that error.
Configure the humidity output channel to deliver relative humidity, absolute humidity, dew point, or enthalpy via NFC. Default is %RH; change in the field via the Belimo Duct Sensor Assistant App without re-wiring or removing the sensor.
±2% RH accuracy across 0-80% RH at 77°F. Long-term stability ±0.3% RH per year. Stainless steel wire mesh filter protects the polymer element from particulate contamination. 10-second time constant in moving air.
Tap a phone with NFC to the housing to read live values, change output mode, adjust CO2/dewpoint range mappings, set Modbus/BACnet addresses (where applicable), and view diagnostics. The Belimo Duct Sensor Assistant App is free for iOS and Android.
UV-resistant polycarbonate enclosure with NBR70 seal. UL94 5VA flame class and UL 2043 plenum compliant for return-air ducts.
Industry-leading factory warranty backed by Belimo's worldwide service network.
Selectable Humidity Output Modes
The active humidity output channel can be configured to deliver any of four values via NFC and the Belimo Duct Sensor Assistant App. The default is relative humidity (%RH) — change the mode in the field to match your control logic.
| Output Mode | Range | Typical Use |
|---|---|---|
| Relative Humidity (%RH) | 0–100% RH non-condensing | Default — most common BAS humidity input |
| Absolute Humidity | 0–50 g/m³ (default) or 0–80 g/m³ | For dehumidification control, dewpoint-based loads |
| Dew Point | 40–140°F (default) or 0–200°F | For condensation prevention on chilled surfaces |
| Enthalpy | 0–85 kJ/kg | For economizer changeover (energy-based instead of dry-bulb) |
Technical Specifications
| Specification | Detail |
|---|---|
| Sensor Style | Outdoor Humidity / Temperature Sensor with Radiated Heat Shield |
| Measured Values | Relative humidity, absolute humidity, dew point, enthalpy, temperature |
| Humidity Sensing Element | Polymer-based capacitive sensor with stainless steel wire mesh filter |
| Humidity Measuring Range | 0–100% RH non-condensing |
| Humidity Accuracy | ±2% RH between 0–80% RH at 77°F (25°C) |
| Humidity Long-Term Stability | ±0.3% RH per year at 70°F (21°C), 50% RH |
| Humidity Time Constant τ (63%) | Typical 10 s @ 3 m/s air velocity |
| Humidity Output | 4–20 mA (loop output) — max. 500 Ω loop resistance |
| Temperature Sensing Element | NTC 10K Type III (Precon) thermistor |
| Temperature Output | NTC 10K Type III (Precon) thermistor passive output (passive — controller reads element directly) |
| Temperature Measuring Range | -30 to 175°F (-35 to 80°C) |
| Temperature Accuracy | ±0.5°F (±0.3°C) — varies by element, see datasheet for full detail |
| Default Output Mode (Humidity) | Relative humidity (%RH); change via NFC to absolute / dewpoint / enthalpy |
| NFC Configuration | Yes — Belimo Duct Sensor Assistant App (iOS / Android) |
| Application | Outdoor air |
| Mounting | Exterior wall mount; radiated heat shield with mounting bracket included |
| Power Supply | 24 VAC/VDC (21.6–26.4 VAC, 13.5–26.4 VDC) |
| Power Consumption | 0.8 VA AC / 0.4 W DC |
| Electrical Connection | Pluggable spring-loaded terminal block, max 2.5 mm² |
| Cable Entry | 1/2" NPT conduit adapter included; cable gland with strain relief, ø6...8 mm |
| Housing | UV-resistant polycarbonate, orange — UL94 5VA |
| Enclosure Rating | NEMA 4X / IP65 (UL Enclosure Type 4X), UL 2043 plenum compliant |
| Protection Class | IEC/EN III, SELV; UL Class 2 supply |
| UL Approval | cULus per UL60730-1A/-2-9, CAN/CSA E60730-1/-2-9 |
| Manufacturer | Belimo |
| Manufacturer Part Number | 22UTH-530M |
| Warranty | 5-year factory warranty |
What's In the Box
- 22UTH-530M active humidity + temperature transmitter in orange UV-resistant housing
- Radiated heat shield (curved white plate)
- Wall mounting bracket
- 1/2" NPT conduit adapter
- Mounting screws and dowels
Documentation
Frequently Asked Questions
What does the 22UTH-530M measure and output?
It measures outdoor air humidity and temperature and outputs both as analog signals. The humidity output is 4–20 mA (loop output); the temperature output is a PASSIVE NTC 10K Type III (Precon) thermistor passive output (your controller reads the element directly). The humidity channel is also configurable via NFC to output absolute humidity, dew point, or enthalpy instead of %RH.
How do I configure the humidity output mode?
Tap an NFC-equipped phone with the Belimo Duct Sensor Assistant App against the housing. The app reads the current configuration, lets you switch the humidity output between %RH, absolute humidity, dew point, or enthalpy, and writes the new configuration back to the sensor — all without removing the sensor or disconnecting wires. Default is %RH. The app is free for iOS and Android.
What does the 'M' suffix mean?
The suffix selects the temperature output type. M = NTC 10K Type III (Precon) thermistor passive output. Other variants in the same family swap the temperature output to a different element: B=Pt 1000, E=Ni 1000 (JCI), L=NTC 10K Type II, M=NTC 10K Type III (Precon), Q=NTC 20K. Match the suffix to your controller's input curve. For an active analog temperature output instead of passive, choose the no-suffix variant (22UTH-530).
Why does this variant have a radiated heat shield?
The radiated heat shield is a curved white plate that protects the sensor elements from rain AND from radiated heat off rooftops, south-facing walls, and reflective surfaces. Without a shield, an outdoor sensor mounted near a black asphalt roof or a south-facing wall can read 5-15°F higher than true ambient on summer afternoons. The radiated shield variants are essential for any rooftop or sun-exposed install. For shaded or north-facing mount locations, the basic-shield variants (22UTH-51 or 22UTH-53) are sufficient.
What is the difference between humidity, dewpoint, and enthalpy as control inputs?
Relative humidity (%RH) tells you how saturated the air is at its current temperature — the most common input for indoor humidity control and dehumidification. Absolute humidity (g/m³) gives the total moisture content regardless of temperature — useful for mass-balance ventilation calculations. Dewpoint tells you the temperature at which moisture will start condensing — ideal for chilled-surface condensation prevention. Enthalpy (kJ/kg) is the total energy content of the air (sensible + latent) — the preferred input for ASHRAE-compliant economizer changeover, where the comparison should be energy-based rather than dry-bulb-temperature-based. Configure the output to match your control sequence.
Does it need 24V power?
Yes. Power is 24 VAC or 24 VDC. Power consumption is 0.8 VA AC / 0.4 W DC.
- Sensor Type:
- Outside Air
- Output Signal:
- Humidity + Temperature
- Humidity Output:
- 4–20 mA (loop output)
- Temperature Output:
- NTC 10K Type III (Precon) thermistor passive output
- Power:
- 24 VAC/VDC
- Humidity Element:
- Polymer Capacitive
- Temperature Element:
- 10K Type III
- Selectable Humidity Modes:
- RH / Absolute / Dew Point / Enthalpy
- Default Humidity Mode:
- Relative Humidity (%RH)
- NFC Configuration:
- Yes (Belimo Duct Sensor Assistant App)
- CO2 Element:
- None
- VOC Element:
- None
- Display:
- No Display
- Setpoint:
- No Setpoint
- Override:
- No Override
- Supported Protocols:
- None (analog)
- Enclosure:
- NEMA 4X Enclosure
- Weather Protection:
- Radiated Heat Shield
