Description - Basic Documentation - RDF600KN - RDF600KN/S - RDF600KN/VB

Semi-flush mount room thermostats with KNX communications RDF301, RDF301.50, RDF301.50H, RDF600KN, RDF600KN/VB, RDF600KN/S

Product Family
Desigo PX Open
Desigo Open
Product Group
Thermostats (temperature controller with sensor)
Building automation
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Technical Documentation > Basic Documentation
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Comfort mode

The factory setting for the Comfort basic setpoint is 21 °C and can be changed in the thermostat’s EEPROM via parameter P08 or via bus with communication object "Comfort basic setpoint". The last intervention always wins.

The Comfort setpoint can be adjusted via the +/- buttons,
or via bus from a remote device like a touchpanel, operating unit, etc.
The last intervention always wins.

Temporary setpoint

If the "Temporary setpoint" function is enabled via parameter P69, the Comfort setpoint adjusted via the +/- buttons or via bus is set back to the Comfort basic setpoint stored in P08 when the operating mode changes.

Setpoint limitation

For comfort or energy saving purposes, the setpoint setting range can be limited to minimum (P09) and maximum (P10).

P09 < P10
(comfort concept)

  • If the minimum limit P09 is set lower than the maximum limit P10, both heating and cooling are adjustable between these 2 limits.

  • The customer adjusts the desired setpoint and the thermostat controls the room temperature accordingly.

  • For 4-pipe applications *), the selected comfort setpoint is in the middle of the dead zone (P33). The unit stops to energize the heating / cooling outputs as soon as the room temperature reaches the dead zone.


Cooling setpoint adjustable 18…25 °C

Heating setpoint adjustable 18…25 °C

P09 ≥ P10
(energy saving concept)

  • If the minimum limit P09 is set higher than the limit P10, then

  • The setting range of cooling setpoint is from P09…40 °C in place of 5…40 °C

  • The setting range of heating setpoint is from 5…P10 °C in place of 5…40 °C.

    This allows the user to limit the maximum heating setpoint and the minimum cooling setpoint. This concept helps to save energy costs.

  • For 4-pipe applications *):

  • The thermostat runs with the setpoint of the active sequence:
    In heating mode, the heating setpoint is active and adjustable via rotary knob. In cooling mode, the cooling setpoint is active and adjustable via rotary knob.

  • Switching from the heating setpoint to the cooling setpoint and vice-versa occurs when the room temperature reaches the adjusted limitation (P09 or P10) of the inactive sequence. E.g. the thermostat is in heating sequence and runs with the heating setpoint. When the room temperature reaches P09, the thermostat switches to cooling mode and runs with the cooling setpoint, as long as the room temperature does not drop below P10.


Cooling setpoint adjustable 25…40 °C

Heating setpoint adjustable 5…21 °C

*) Note: RDF301...
for 4-pipe with P09 ≥ P10

For heating and cooling applications (e.g. 4-pipe):
P09 is the setpoint for cooling and P10 the setpoint for heating.
– The setpoint cannot be adjusted via the rotary knob.

Economy mode

Use control parameters P11 and P12 to adjust the Economy mode setpoints.

The heating setpoint is factory-set to 15 °C, and the cooling setpoint to 30 °C.

Protection mode

Use control parameters P65 and P66 to adjust the Protection mode setpoints.
The heating setpoint is factory-set to 8 °C (frost protection) and to OFF for cooling.


If a setpoint (Economy or Protection) is set to OFF, the thermostat does not control the room temperature in the corresponding mode (heating or cooling).

This means no protective heating or cooling function and thus risk of frost in heating mode or risk of overtemperature in cooling mode!

The Economy setpoints are accessible at the service level (P11, P12); the Protection setpoints at the expert level (P65, P66).