User Manual

Functions
Additiona
l functions
4
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these functions are required, the total maximum current on the relay outputs
(Q1+Q2+Q3) must not exceed 2 A.
The relay output function can be enabled and tested as follows:
Relay output function on
…
Enable function via Expert
level parameter
Test function via
diagnostic parameter
Q1 P400 d08
Q2 P401 d09
Q3 P402 d10
The external equipment (for example, fan coil unit) can be switched off via relay
output for energy savings when the thermostat is in Protection mode and no
temperature control is requested.
Set the related output parameter to 1 to enable the function.
Relay contact is open when the thermostat is in Protection mode.
NOTICE! The relay contact will not switch on when the room temperature is below
the frost protection setpoint.
For application examples, see Relay functions [➙ 132].
During heating or cooling demand, the relay contact can be energized to control
external equipment, for example, to run the pump for a water system (fan coil unit)
or a compressor.
To reduce wear and tear on HVAC equipment, the minimum output On/Off time of
the Qx relay output can be adjusted (1…20 minutes) via P212 and P213. The
factory setting is 1 minute.
To enable the function, set the related output parameter:
● To energize the output during heating/cooling demand, set the parameter to 2.
● To energize the output during heating demand, set the parameter to 3.
● To energize the output during cooling demand, set the parameter to 4.
For application examples, see Relay functions [➙ 132].
● During heating demand, the relay contact remains OFF only with electric heater
or radiator (output signal on Y2/Y20 > 0 V).
● If the purge function (P251) is active (1…5 minutes every 2 hours), the relay
contact turns ON to run the external equipment, for example, a water pump.
This function switches the relay output on or off depending on the sequence, either
heating or cooling. The output can be used for the release of a heat pump
compressor, a reversing valve or 6-port ball valve as changeover.
To enable the function, set the related output parameter:
● To close the contact when the thermostat is in heating mode (even in the dead
zone), set the parameter to 5.
● To close the contact when the thermostat is in cooling mode (even in the dead
zone), set the parameter to 6.
For application examples, see Relay functions [➙ 132].
To reduce wear and tear on HVAC equipment, the minimum output On/Off time of
the Qx relay output can be adjusted (1…20 minutes) via P212 and P213. The
factory setting is 1 minute.
Depending on the humidity in the room and the humidity setpoint, the humidity
control function switches the relay outputs to control the external equipment, for
example, dehumidifier/humidifier. See Humidity control [➙ 129].
To enable the function, set the related output parameter:
● To control the dehumidifier, set the parameter to 7
● To control the humidifier, set the parameter to 8
Switching off external
equipment in Protection
mode
Energizing the contact
during heating/cooling
demand
Notes
Output heating/cooling
sequence
Humidity control