Description
BACnet-ready CO₂ transmitter with LCD display, buzzer, and onboard relays in a NEMA 4X enclosure
The QEL B5-CO2-5000P-0-A is a smart CO₂ sensor/transmitter designed to plug straight into a building automation system and drive ventilation when carbon dioxide levels rise. Using an infrared sensor to measure CO₂ from 0–5,000 ppm, it provides stable readings for offices, garages, classrooms, and other occupied spaces where air quality matters.
A bright LCD shows live CO₂ levels, while status LEDs and an integral buzzer make local alarms hard to miss. Three built-in relays can directly start fans, open dampers, or trigger remote alarms when CO₂ crosses your chosen setpoints so no extra relay panel is required.
The B5 series is housed in a rugged NEMA 4X enclosure that stands up to dust, moisture, and tough mechanical spaces. Pre-calibrated sensor modules can be swapped in the field with just a couple of screws, helping reduce calibration downtime and service costs over the life of the system.
Key Features or Benefits
Reliable CO₂ Monitoring up to 5,000 ppm
Non-dispersive infrared (NDIR) sensing provides accurate CO₂ readings over a 0–5,000 ppm range, suitable for demand-controlled ventilation and indoor air quality monitoring.
Built-in Display, Buzzer, and Relays
The front LCD shows gas concentration and setup data, while LEDs indicate relay and communication status. An 80 dB buzzer and three SPDT relays give you local audible alarms and direct control outputs without extra hardware.
Direct BACnet Integration
Uses BACnet MS/TP over RS-485, so your BAS can read CO₂ values, see alarm status, and manage relay behavior using a standard open protocol, no special gateway required.
Tough, Sealed Enclosure for Demanding Areas
NEMA 4/4X/12/13 enclosure protects electronics from dust, water spray, and corrosion, making this transmitter a good fit for garages, mechanical rooms, and other harsh spaces as well as cleaner indoor environments.
Field-Replaceable, Pre-Calibrated Sensor Modules
Factory-calibrated sensor/board assemblies can be ordered and installed by the user, reducing the need for on-site calibration equipment and cutting system downtime during service.
Flexible Outputs for Different Control Strategies
In addition to BACnet communications, the B5 series offers 4–20 mA and voltage outputs (1–5 V or 2–10 V) that can be tied into drives, PLCs, or other controllers for CO₂-based ventilation control.
Designed for Real-World Applications
Typical uses include parking garages, mechanical rooms, warehouses, labs, and other spaces where code or owner standards call for monitoring CO₂ and automatically responding when levels rise.
Key Specs
- Measurement Range: 0–5,000 ppm CO₂
- Sensor Type: infrared (NDIR) CO₂ sensor
- Outputs (electrical): BACnet MS/TP (RS-485), 4–20 mA, 1–5 VDC, 2–10 VDC
- Relays: 3 × SPDT relay outputs, 1 A @ 30 VDC (typ.)
- Audible Alarm: integral buzzer, ~80 dBA @ 3 ft
- Enclosure Rating: NEMA 4/4X/12/13 plastic enclosure
- Supply Voltage: 15–24 VAC @ ~7.2 VA; 18–30 VDC @ ~300 mA
- Display: backlit LCD with status LEDs
