Belimo 22DCK-51 : Active Duct Air Quality Transmitter, CO2 + VOC + Temperature + CO2/VOC Mix, 0–5V / 0–10V Output, NDIR Dual-Channel CO2, 4 Analog Outputs, NEMA 4X / IP65, 24 VAC/VDC (°F + NPT), 5-Year Warranty

What does the 22DCK-51 measure?

This SKU measures CO2, VOC, Temperature, CO2/VOC Mix. Each measurement has its own dedicated analog output (4 outputs total), so each value can be wired to a separate BAS analog input simultaneously.

What output signals can this provide?

All 4 analog outputs are voltage-only: jumper-selectable between 0-5V and 0-10V per channel, minimum 10 kΩ load resistance. For a 4-20 mA output option, see the universal-output 22DCK-53 variant of this same product.

What is the difference between the -11/-13 and -51/-53 variants?

The suffix encodes regional configuration. -51 and -53 are the North American variants: temperature output configured in Fahrenheit, A-22D-A34 mounting flange (NPT 19.5 mm), and a 1/2" NPT conduit adapter included. -11 and -13 are the international (EU) variants: Celsius temperature output, A-22D-A35 mounting flange, no NPT adapter (M16/M20 metric conduit). Same electronics, same accuracy, same outputs — the difference is regional preference for units and conduit standard. This SKU is the North American variant; the cross-region counterpart is 22DCK-11.

How does NDIR dual-channel CO2 sensing work?

NDIR (non-dispersive infrared) measures CO2 by detecting how much infrared light the gas absorbs at a specific wavelength. The 'dual-channel' design uses a second reference wavelength that CO2 does NOT absorb — by comparing the two signals, the sensor automatically corrects for lamp aging, dirt accumulation on the optics, and background gas interference. This is why the sensor is self-calibrating and rated for ±50 ppm/year long-term stability without manual recalibration.

What does VOC measure and what range does it cover?

VOC = Volatile Organic Compounds — gases released by paints, solvents, cleaning products, off-gassing materials, cooking, and combustion. The metal oxide semiconductor sensor measures total VOC (TVOC) from 0-100% relative concentration (equivalent to roughly 0-5000 ppb TVOC). Output scales linearly across the range. VOC is typically monitored as a relative trend rather than a calibrated absolute value — a sudden VOC spike is a meaningful BAS event regardless of the absolute ppb number.

What is the CO2/VOC mix output for?

The 'mix' output is a single combined air quality index that weights both CO2 and VOC into one value. Useful for controllers that want a single damper modulation signal driven by overall air quality rather than two separate inputs. The DCK variant is the only Wave 2 SKU that includes this output — choose DCM (no mix) or DCV (no temperature, no mix) if your application doesn't need it.

How do I choose between DCK, DCM, and DCV?

DCK = CO2 + VOC + Temperature + CO2/VOC Mix (4 outputs, max IAQ coverage). DCM = CO2 + VOC + Temperature (3 outputs, no mix value). DCV = CO2 + VOC only (2 outputs, no temperature). Choose by which signals your BAS actually uses — there's no benefit to paying for outputs you won't wire. If you need temperature at the same duct location and want to consolidate sensors, DCM or DCK eliminate a separate 22DT install.

Can I use this just for temperature?

Yes, but it's overpriced for that use — if you only need duct temperature, the single-variable 22DT family is significantly cheaper and provides 8 selectable measuring ranges that this combo sensor does not. Use the integrated temp output here only when you also need CO2 and/or VOC at the same location.

Does it need 24V power?

Yes. The 22DCK-51 requires 24 VAC or 24 VDC (19-29 VAC, 15-35 VDC). Power consumption is 4.3 VA AC / 2.3 W DC — higher than single-variable temperature sensors due to the active CO2 NDIR sensing element.

What air velocity does it need to operate?

Operating air flow range is 1-40 ft/s (0.3-12 m/s). The CO2 NDIR cell needs some air movement past the probe to refresh the gas sample for accurate readings. Below 1 ft/s the reading lags actual duct air composition; above 40 ft/s the response stays accurate but probe vibration becomes a long-term wear concern.

Can I configure this sensor with the Belimo Duct Sensor Assistant App?

Yes. The Belimo Duct Sensor Assistant App (iOS / Android) connects to this sensor via the A-22G-A05 Bluetooth dongle for parametrization — adjusting CO2 scaling (2000 / 5000 ppm), output mapping, and (on multi-variable sensors) the CO2/VOC mix ratio. Most installations don't require this — the sensor arrives pre-configured with sensible defaults — but it's available for advanced or non-standard applications. See the Documentation section above for the app brochure.