The Belimo 22RTM-58L0A is a wall-mount active room sensor measuring CO2, Relative Humidity, Dew Point, and Temperature with NFC commissioning for tap-and-configure setup via the Belimo Assistant App and an MP-Bus channel for digital network integration. Occupants view current values and adjust setpoints by tapping a smartphone to the device's NFC zone via the Belimo Display App. An onboard LED provides at-a-glance indoor air quality status when CO2 measurement is enabled. The sleek white (RAL 9003) housing matches commercial interior finishes and mounts to a single-gang box or flat to drywall.
Key Features
NFC Commissioning
Tap a smartphone with the Belimo Assistant App to read or write any configuration parameter — output scaling, measuring ranges, setpoint limits — without connecting to a panel or BAS. Slashes commissioning time on multi-room installations.
MP-Bus Digital Channel
In addition to analog outputs, the device acts as a node on Belimo's MP-Bus network (up to 8 standard or 16 special nodes per master), allowing digital readout and configuration from compatible Belimo controllers.
Belimo Display App + LED
Smartphone-based occupant interface — tap the phone to the sensor and the app shows live readings and lets the occupant adjust the temperature setpoint within BAS-defined limits. Optional 4-digit access code prevents unauthorized changes. The onboard LED also provides traffic-light indication of CO2 levels when measurement is enabled (configurable via Belimo Assistant 2).
Selectable V or 4-20 mA Outputs
Each analog channel can be configured for 0-5 V, 0-10 V, 2-10 V, or 4-20 mA via the Belimo Assistant 2 app — drop into any controller, including legacy current-loop systems and long-cable-run installations.
NDIR Dual-Channel CO2 Sensor
Non-dispersive infrared dual-channel CO2 element compensates for sensor aging without requiring weekly fresh-air calibration (ABC logic). Suitable for 24/7 occupancy applications. Recommended recalibration after 5 years.
Capacitive Humidity Sensor
Long-term-stable capacitive RH element with ±2% accuracy between 0-90% RH at 25°C and ±0.25% RH/year drift. Dew point is calculated and provided as an additional measured value.
Configurable Setpoint Range
Define how far the occupant can shift the setpoint above or below the BAS schedule. All limits, scaling, and offsets are configurable via the Belimo Assistant App or BAS object writes — no DIP switches, no jumpers.
Universal 24 V Power
AC/DC 24 V (19.2-28.8 V) supply tolerance. Spring-loaded terminals accept 0.25-1.5 mm² conductors with back, top, or bottom cable entry — flexible mounting for both new construction and retrofit.
Technical Specifications
| Specification | |
|---|---|
| Measured Values | CO2, Relative Humidity, Dew Point, Temperature |
| Output Signal | 2x Selectable 0-5 V / 0-10 V / 2-10 V or 4-20 mA (CO2 + humidity) + NTC10k Type II passive (temperature) |
| Communication | NFC + MP-Bus |
| Temperature Range | 32...122°F [0...50°C] (default, configurable) |
| Temperature Element (Passive) | NTC 10k Type II |
| Temperature Accuracy (Active) | ±0.5°C @ 25°C [±0.9°F @ 77°F] |
| Temperature Accuracy (Passive) | ±0.2°C @ 25°C [±0.35°F @ 77°F] |
| Humidity Range | 0...100% RH (default, configurable) |
| Humidity Accuracy | ±2% between 0...90% RH @ 77°F [25°C] |
| Humidity Long-Term Stability | ±0.25% RH per year |
| Dew Point Range | -58...122°F [-50...50°C] |
| CO2 Sensor Technology | NDIR (Non-Dispersive Infrared) Dual-Channel |
| CO2 Range | 0...2000 ppm (default, configurable) |
| CO2 Accuracy | ±(50 ppm + 2% of measured value) |
| CO2 Long-Term Stability | ±20 ppm per year |
| Display | Belimo Display App + LED |
| Setpoint Adjustment | Yes (via Display App / NFC) |
| Nominal Voltage | AC/DC 24 V |
| Voltage Range | 19.2...28.8 V (AC or DC) |
| Power Consumption | Max 1 VA AC / 0.5 W DC (V output); Max 4 VA AC / 2 W DC (mA output) |
| Electrical Connection | Spring-loaded terminal 0.25-1.5 mm² |
| Cable Entry | Back, top, and bottom side |
| Housing | PC, white, RAL 9003 |
| Protection | IP30 / NEMA 1 |
| Ambient Temperature | 32...122°F [0...50°C] |
| Ambient Humidity | Max 95% RH, non-condensing |
| Storage Temperature | -40...160°F [-40...70°C] |
| Certifications | UL/cULus per UL60730-1, IEC/EN 60730-1, CE, ISO 9001 |
| Warranty | 5 Years |
Documentation
Frequently Asked Questions
What does the 22RTM-58L0A actually measure?
The 22RTM-58L0A measures co2, relative humidity, dew point, temperature (calculated). All values are available simultaneously over nfc + mp-bus.
How do I switch the analog outputs between voltage and 4-20 mA?
Use the Belimo Assistant 2 mobile app over NFC. Select the channel, choose 0-5 V, 0-10 V, 2-10 V, or 4-20 mA, and write back to the device. No DIP switches or jumpers — and no need to open the housing.
How does the occupant change the setpoint without a physical dial?
Occupants download the free Belimo Display App, tap their phone to the sensor's NFC zone, and view current readings or adjust the temperature setpoint. An optional 4-digit access code prevents unauthorized adjustments. For occupants without smartphones, the BAS or a wall thermostat can also drive the setpoint.
Does the CO2 sensor need regular calibration?
The CO2 element uses NDIR dual-channel technology, which compensates for component aging using a sealed reference duct — fresh-air ABC calibration is not required. This makes it suitable for 24/7 occupied spaces where ABC sensors would never see clean outdoor air. Recalibration is recommended after 5 years.
Why does this variant have a passive temperature output?
The NTC10k Type II resistance output gives you ±0.2°C accuracy for temperature (versus ±0.5°C on the active V output) and matches the input curve already wired in many existing controllers. It's the easiest way to retrofit a NTC10k-based controller while still gaining humidity and CO2 from the same wall location.
What's the power draw?
Up to 1 VA AC or 0.5 W DC when configured for V output, and up to 4 VA AC or 2 W DC when configured for 4-20 mA output (each loop draws 20 mA continuously). Spec the 24 V transformer accordingly when using current-loop outputs.
How does this mount?
PC housing in white RAL 9003 mounts directly to a single-gang electrical box (back-side cable entry) or flat to drywall (top or bottom cable entry). Spring-loaded terminals accept 0.25-1.5 mm² conductors — no screws to overtighten.
