On/Off control

The thermostat controls an On/Off valve actuator for heating applications.

RDD210.V..

Heating mode

T[°C]

Room temperature

W

Room temperature setpoint

YH

Control command “Valve” (heating)

SDH

Switching differential “Heating”

On/Off control signal for Comfort or Economy (P02 = 2)

The valve receives the On command via control outputs Q12 or Q14 when:

  1. The acquired room temperature is below the setpoint (heating)
  2. The control output was not energized for more than the “Minimum output off time” (factory setting 1 minute)

 

The valve receives the Off command when:

  1. The acquired room temperature is above the setpoint (heating)
  2. The control output was energized for more than the “Minimum output on time”; (factory setting 1 minute)

 

On/Off control signal for Protection

The factory setting for the heating setpoint in Protection (P65) is 8 °C.

In Protection, the thermostat is normally turned off and the output is not energized.

When the room temperature drops below 8 °C, the control output is activated to prevent water from freezing in the pipes.

The Protection setpoint can be adjusted via P65. When P65 is set to Off, anti-freeze protection is disabled.

Note:

  • Control output Q12 provides an inverted control command to output Q14 for normally open valves.
  • The valve output responds immediately and does not consider minimum On/Off time, if the setpoint is adjusted manually via the local HMI.

Floor limitation sensor via external input

An external floor limitation sensor is connected to the thermostat via input terminals X1 and M.

When the floor heating temperature limitation function is enabled (P51 ≠ 0) and the floor temperature is above the setpoint, the floor heating output is forced to Off to protect the floorboards from getting overheated or burnt.