RDG204KN KNX Room Thermostat with CO2 Sensor
The RDG204KN is a KNX room thermostat featuring integrated CO2 sensing, enabling demand-controlled ventilation alongside temperature-based HVAC regulation. This advanced combination is ideal for occupied spaces where CO2 accumulation impacts cognitive function — including classrooms, meeting rooms, open-plan offices, auditoriums, and dense work areas.
Key Innovation: Continuous CO2 detection displaying values in ppm numerically or via text indicators. When CO2 exceeds configurable thresholds, it automatically increases outdoor air damper positions, activates supplementary ventilation, or sends BMS alerts through KNX group communication.
Technical Specifications
| Sensor Capabilities |
Integrated temperature, humidity, and CO2 sensors |
| Output Architecture |
Modulating (PWM/3-position) or on/off signals for valves; 3-speed or DC fan coil outputs; 3 analog inputs; 2 analog outputs (fresh air damper DC 0...10 V) |
| Control Outputs |
3 digital inputs; 3 relay outputs (fan 1-/3-speed AC 24-230 V, valve/heater switching); 4 triac outputs for valve actuation at AC 24...230 V / 1 A |
| Operating Voltages |
AC 230 V or AC 24 V |
| Housing |
Ivory white RAL 9001 |
| Documentation |
Data sheet A6V11545853 |
Application Systems
- 2-pipe systems (electrical heater, radiator/floor, 2-stage heat/cool)
- 4-pipe systems with electrical heating
- 4-pipe 2-stage heat/cool including alternative 2-cool/1-heat modes
- Fan coil 3-speed / DC fan universal heating/cooling applications
- VAV fresh air systems
Ventilation Control Features
Supports fresh air damper control for comprehensive indoor air quality management. The integrated CO2 sensor enables smart ventilation strategies that respond to actual occupancy levels, optimizing energy efficiency while maintaining superior air quality.