Defrost Function For Air-To-Water Heat Pumps - Siemens RVS41.813 User Manual

Defrost function for air-to-water heat pumps

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Siemens Switzerland Ltd
HVAC Products
The heat pump only participates in the full charge, if it is in operation and the function is
switched on via the parameter full charge of buffer storage tank . Maintains the heat
pump's minimum runtime .
Off.
The heat pump remains locked until the buffer storage tank is fully charged by some
other heat source. It is released only when there is not enough heat for satisfying the
current demand (4720).
On.
The heat pump is released when the buffer storage tank is fully charged.
Defrosting of an iced-up evaporator is effected either with the fan or the compressor by
reversing the process – independent of the outside temperature:
•
Above the set outside air temperature (Par OEM 2971) using the fan (passive
defrost)
•
Below the set outside air temperature (Par OEM 2971) using the process
reversal (active defrost)
The example below shows a heat pump in heating mode and in defrosting mode with
process reversal.
Up to the outside temperature "Defrost fan above" (2971) set here, defrosting takes
place with the fan. If the outside temperature falls below this level, defrosting is
accomplished by reversing the process with the help of the compressor. If the two
parameters 2971 "Defrost fan above" and parameter 2951 "Defrost release below OT"
are set to the same value, defrosting starts directly with active defrosting "Defrost with
process revers".
T min
Defrost time
fan max
Par 2973
Defrost time
fan min
Par 2972
Defrost with
process revers
Defrost fan above Temp
User manual RVS61.843, RVS41.813
6 The settings in detail
Defrost with
fan
Par 2971
B91
2951:
2971 OEM: Defrost fan above
2972 OEM: Defrost time fan min
2973 OEM: Defrost time fan max
Defrost
locked
B91 (°C)
Par 2951
Defrost release
below Temp B91
Defrost release below OT
CE1U2355en_02
28. September 2009