Siemens RDG20 KN Series Basic Documentation page 61

Note
Setpoint (P024, P025,
P026)
Setpoint high
Setpoint low
Dehumidification
Note
Dehumidification
A6V11545892_en--_e
–
If the parameter is set to Send (factory setting), the thermostat can display
the humidity value measured by the built-in sensor and the value is sent to
the bus.
2. LTE-Mode
The thermostat displays the relative humidity value on the bus if the external
KNX sensor is in the same geographic zone apartment and room (A.R.1) as
the thermostat.
3. In other cases, the thermostat displays the humidity value measured by the
built-in sensor.
To display room humidity (%) on the thermostat, P009 needs to be set to 5.
The high humidity setpoint (%) is selected via P024 or P025 (setpoint humidity high
Comfort and Economy) and can be adjusted via parameters in Service level or via
bus.
Setting P024 or P025 to Off disables high humidity control.
The low humidity setpoint (%) is selectable via P026 (setpoint humidity low) and
can be adjusted via parameters in Service level or via bus.
Setting P026 to OFF (default setting) disables low humidity control. The setting
range is limited by P024.
S-Mode objects for the humidity setpoint are available, if the parameter "Humidity
setpoints" is set to as group object in ETS.
When relative humidity exceeds the high setpoint, the thermostat shifts the
temperature setpoint proportionally until P461 (max. shift temp setpoint) is
reached. If this control does not sufficiently reduce humidity, an external
dehumidifier can be switched on via relay outputs or KNX and related relay
function (P400, P401 or P402 is set to 7).
The maximum temperature shift setpoint value is reached at setpoint humidity high
(P024) +10%. The contact for the dehumidifier is released at setpoint humidity
+15%.
Applications with a DC 0...10 V fan:
●
Enable the function to control the external dehumidifier directly via relay output
by setting P400 (output Q1), P401 (output Q2) or P402 (output Q3) to 7.
When the output is energized, S-Mode object dehumidification sends the
information "ON" to the bus
●
The selected relay output is switched on if relative humidity exceeds the high
setpoint by +15%.
●
For applications with On/Off valves on Q1 or Q2 or both, the output Q3
(P402 = 7) is used to control the external dehumidifier.
●
The relay contact remains closed or open for the minimum On/Off time defined
by P212 or P213.
4
Functions
Additional functions
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