General note:

Setting control parameters (P01 etc. mentioned throughout the document), see Control parameters.

Temperature control

The thermostat acquires the room temperature via built-in sensor, external room temperature sensor (NTC 3k or NTC 10k) or via bus, and maintains the setpoint by delivering actuator control commands to heating equipment, cooling equipment, or both. The following control output is available:

  • 2-wire or 3-wire On/Off valve actuator (RDF400.., RDF460..)
  • 3-position valve actuator (RDF400.., RDF460..)
  • DC 0...10 V valve actuator (RDF440..)

The hysteresis is 2 K in heating (adjustable via parameter P43) and 1 K in cooling (adjustable via parameter P44).

The proportional band is 2 K for heating mode and 1 K for cooling mode (DC and 3-pos valves: P43 and P44).

The integral action time for modulating PI control is adjustable via P45 (factory setting: 45 minutes).


The display shows the acquired room temperature or the Comfort setpoint, selectable via P11. The factory setting displays the current room temperature.

Configure P12 to display the room temperature or setpoint in °F or °C as needed.


When P11 = 2, the Comfort setpoint is always displayed even when the operating mode changes.

Room temperature

The acquired room temperature (internal or external sensor) is available as information on the bus.

Thermostat can also acquire the room temperature via bus.

  • With automatic changeover or continuous heating/cooling, symbols indicate that the system is currently heating or cooling.
  • With manual changeover (P02 = 4), symbols indicate that the system currently is in heating or cooling mode. Thus, the symbols are displayed even when the thermostat operates in the zero energy zone.

Concurrent display of °C and °F

Concurrent display of the current temperature or setpoint in °C and °F is available (P14 = 2) on the thermostat.

Temperature setpoint

The temperature setpoint can be shown on the primary display when P11 = 2 and secondary display when P14 = 3 & P11 = 1 or 3.

Time of day

Time of day via bus can be displayed on the room thermostat by setting P14 = 4. The display format is in 12-hour format.

The information can be received from a client device in the BACnet/Modbus network.