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Siemens Switzerland Ltd 
User manual RVS61.843 CE1U2355en_02 
HVAC Products  6 The settings in detail  23. November 2007 
Source pump 
 
TQa
t
°C
Q8
1
0
 2817
2815 /
2816
OFF
K1
ON
0
Anf
1
 2822
 2821
 2821
 2819
 2820
 Error
 
2815 Source temp min water 
2817 Switching diff source prot 
2821 Source startup time max 
2822  Time limit source temp min 
TQa   Source outlet temperature 
K1 Compressor 1 
Q8 Source pump 
Anf Heat request 
 
Line no.  Operating line 
2815  Source temp min water 
2816  Source temp min brine 
2817  Switching diff source prot 
2818  Increase source prot temp 
2819  Prerun time source  
2820  Overrun time source  
2821  Source startup time max 
2822  Time limit source temp min 
 
This function prevents the heat pump from operating at too low source outlet 
temperatures. It is intended for plants that use water as the heat source. 
If, during operation, the source outlet temperature drops below the “Source temp min 
water”, the pumps and the compressor are switched off for the “Time limit source temp 
min” (2822).  
This function is intended for plants that use the ground as a heat source and is aimed 
at preventing the source temperature from dropping excessively. With the exception of 
the following 2 points, this function is identical with function “Source temp min water”: 
•  Function 5804 is used to select whether the temperature at the source inlet or 
source outlet shall be considered 
•  During the time the floor curing function is carried out, the controller raises 
automatically the minimum source temperature by the value set on operating 
line 2818 
The source protection function for brine-to-water heat pumps also applies to setting 
“Heat source = external” on operating line 5800. 
 
After the set maximum source startup time (2821), the source temperature must 
exceed the source protection temperature (2815 or 2816) by at least the “Switching diff 
source prot” (2817) , enabling the compressor to be switched on when there is a valid 
heat request.  
Functional 
interrelationships 
Source temp min water 
Source temp min brine 
 
Switching diff source prot