Series Vents CO2

Series Vents CO2 - Controls - Controls for HRV / ERV
The sensor is designed for indoor carbon dioxide concentration measurement and respective air capacity regulation through the control output signal to the fan. Air capacity control based on CO2 concentration is an efficient energy saving solution

Design and compatability

The sensor has two separate outputs: a normally opened dry relay contact and an analogue output 0…10 V (this output is adjustable for 2…10 V/0…20 mA/4…20 mA). The relay output is used to turn the fan on/off depending on indoor CO2-concentration and the analogue output is used for smooth fan speed control for a fan with EC-motor or a fan with extra speed controller with 0-10 V input. In case of smooth fan speed control, the fan speed varies proportionally to carbon dioxide emissions. The relay and analogue outputs make the sensor compatible with any ventilation system. The integrated self-calibration system ensures reliable sensor operation during the sensor service life.

Mounting and power supply

The sensor is designed for wall surface mounting. 24 VAC low current power supply. If power supply 24 V is not available, connect the TRF plug that is offered as an accessory.


Power supply unit is applied for connection of the sensor to 120 V (TRF-120/24-1.6) AC power mains.

Wiring diagram

HRV/ERV External terminal


The sensor is available in two modifications: CO2-1 and CO2-2. The CO2-1 model incorporates LED lights for CO2 concentration and operation buttons indicating the level of three operation modes: 1 — on, 2 — off, 3 — operation by CO2 concentration. The button is used to switch the ventilation system on or off when CO2 — based ventilation control is not required. The CO2-2 model has no LED-lights and on/off button. The model is applied for premises requiring permanent ventilation, i.e. at school classes and other public premises.

Mounting and power supply

Power supply / consumption24 VAC (50/60 Hz ± 10%), 24 VDC/1.6 W Max
Gas detection analyzerNon-dispersive infrared detector (NDIR)
with self-calibration system
CO2 measuring range0-2,000 ppm (parts per million)
Accuracy at 25 °C, 2,000 ppm±30 ppm + 3 % of reading
Response timemax. 2 min
Warm up time for each turning-on2 hours (first time), 2 minutes (operation)
Analogue output0-10 VDC (default), 4-20 mA selectable by jumpers
On/Off output1X2 A switch load. Four set points selectable by jumpers
6 LED lights for CO2
concentration indication
(for model CO2-1)
1st green indicator lights when CO2 concentration is below 600 ppm;
1st and 2nd green indicators light when CO2 concentration is 600-800 ppm;
1st yellow indicator lights when CO2 concentration is 800-1200 ppm;
1st and 2nd yellow indicators light when CO2 concentration is 1200-1400 ppm;
1st red indicator lights when CO2 concentration is 1400-1600 ppm;
1st and 2nd red indicators light when CO2 concentration is above 1600 ppm
Operating conditions / storage recommendations0-50 °C; 0-95 % RH non condensing/ 0-50 °C
Weight / Dimensions0.120 kg/100 mm x 80 mm x 30 mm

CO2 sensors specification 2023-07
163 Kb
CO2 sensors leaflet 2023-07
142 Kb
350 Kb