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Siemens Switzerland Ltd 
User manual RVS61.843 CE1U2355en_02 
HVAC Products  6 The settings in detail  23. November 2007 
1st speed  
output Q2/Q6/Q20 
2nd speed 
Output Q21/Q22/Q23 
Pump state 
Off Off Off 
On Off Part load 
On On Full load 
 
Diverting valve, cooling Y21 
Control of the diverting valve for cooling. This necessitates a 4-pipe system. The 
diverting valve for cooling is required in the case of a commonly used heating and 
cooling circuit for changeover from heating to cooling when the heat pump is used not 
only for heating but also and 
simultaneously for cooling.  
Q2
HK/KK
T
B1
Y1/Y2
Y21
H
K
 
K
H
 
Example:  
Draw off via 4-pipe system 
 
Dehumidifier K29 
An external dehumidifier can be enabled if the indoor air humidity rises. In this case, a 
humidity sensor must be connected to input Hx. 
The function of the dehumidifier depends on the cooling functions. 
Operation of the dehumidifier is not affected by operating modes, holiday programs, 
presence button, etc. 
 
Heat request K27 
Indicates to an external heat source when there is a request for heat by closing its 
contact. 
 
Refrig demand K28 
As soon as there is refrigeration demand in cooling circuit 1, output K28 is activated. 
This can be used to switch on an external refrigeration machine. 
In the case of device with address 1, a refrigeration demand from the system also can 
activate output K28. For this purpose, operating line 6627 "Refrig demand K28" on 
menu "LPB system" must be set to "Centrally". 
 
Alarm output K10 
If a fault occurs in the controller or the system, one of the alarm relays delivers a signal.  
The relevant contact makes with a delay of 10 minutes. 
When the fault is corrected, that is, when the error message is no longer present, the 
contact opens with no delay.  
 
Time program 5 K13 
The relay switches any connected component at the points in time set in time program 
5 (601 – 616).