Belimo 22DTM-51 Duct CO2 Humidity Temperature Sensor, 0-5V/0-10V, NEMA 4X/IP65

The Belimo 22DTM-51 is a professional-grade active duct insertion sensor that simultaneously measures CO₂ concentration, relative humidity, and temperature in HVAC air ducts. Designed for demanding indoor air quality (IAQ) monitoring applications, it delivers three independent analog output signals from a single device, simplifying wiring and reducing installation costs in building automation systems (BAS).

CO₂ sensing is performed using NDIR (non-dispersive infrared) dual-channel technology with a stainless steel wire mesh filter, providing stable, long-term accuracy without frequent recalibration. The humidity element uses a polymer-based capacitive sensor, also protected by a stainless steel wire mesh filter. All three outputs are jumper-selectable between 0–5 V and 0–10 V DC to match virtually any building automation controller.

Key Features:

• Measures CO₂, relative humidity, and temperature simultaneously with three independent outputs
• NDIR dual-channel CO₂ technology for long-term stability and accuracy
• CO₂ range: 0–2,000 ppm (expandable to 0–5,000 ppm with accessory A-22G-A05)
• Humidity range: 0–100% RH, accuracy ±2% (10–90% RH)
• Temperature range: 40–140°F (4–60°C), accuracy ±0.5°F @ 77°F
• Output signals: 3 × 0–5 V or 0–10 V DC, jumper-selectable, min. 10 kΩ load
• Supply voltage: AC/DC 24 V (AC 19–29 V / DC 15–35 V)
• Power consumption: 4.3 VA (AC) / 2.3 W (DC)
• NEMA 4X / IP65 rated enclosure — suitable for demanding environments
• Probe length: 7" (180 mm), probe diameter: 0.77" (19.5 mm)
• Electrical connection via pluggable spring-loaded terminal block
• Cable entry: cable gland with strain relief, ø6–8 mm (½" NPT conduit adapter included)
• Housing material: polycarbonate (PC), orange; UV resistant, UL94 5VA rated
• Approvals: ISO 9001, UL 2043, UL 50, IEC/EN
• 5-year warranty

What's Included: Sensor unit, mounting flange, and ½" NPT conduit adapter.

The 22DTM-51 is ideal for IAQ monitoring in commercial buildings, laboratories, greenhouses, food and beverage facilities, parking garages, and agricultural environments where precise air quality data is essential for ventilation control and occupant comfort.