The drinking water circuit circulation pump ZP is likewise activated, provided that storage tank
charging is not taking place. Outside of rated operation times for drinking water heating, the
temperature of the drinking water storage tanks is additionally kept at 5 °C, provided that a
storage tank thermostat is not used. In conjunction with a storage tank thermostat, there is no
frost protection outside of rated operation times for drinking water heating.
Note:
There is no frost protection when mode switch is set to manual!
4.13 Defective sensors
symbol appears in the display
The following described controller behavior in the event of a defect refers to a definite short-cir-
cuit and clear interruption in the sensor wiring.
Safety functions such as frost protection and excess temperature protection are therefore guar-
anteed when a sensor fails.
Outdoor temperature sensor AF:
If the outdoor sensor is defect, the controller either regulates a flow temperature set point of 50
°C or the maximum flow temperature, provided it is smaller than 50 °C.
Flow temperature sensor VF:
If this flow sensor fails, the controller continues to operate in the
last position the valve assumed.
Flow temperature sensor for drinking water circuit VF TW, (SF1 in systems 4.1, 4.2):
If this
sensor fails, the drinking water circuit is deactivated; the control valve of the drinking water cir-
cuit remains closed.
Return flow temperature sensor RüF:
If the return flow sensor fails, the control system functions
without return flow temperature limitation.
Room temperature sensor RF:
If this sensor fails, the controller functions according to the set-
tings for operation without room sensor, i.e. it switches from the optimize mode to reduced
operation. If the adaptation mode has been activated, the heating characteristic most recently
determined remains unchanged.
Storage tank temperature sensor SF1 and SF 2:
If one of the two sensors fails, storage tank
charging is not carried out anymore.
Solar circuit sensor SF2 and CF:
If one of the two sensors fails, the solar circuit pump is switched
off.
4.14 Forced operation of the pumps
If the pumps are not used, they are protected from blocking by forced operation. If the heating
circuit circulation pump UP, the storage tank charging pump SLP or the heat exchanger charg-
ing pump are not activated within 24 hours, they are force-operated for one minute as follows:
The circulation pump then starts at 12:00 hrs, storage tank charging pump and the heat ex-
changer charging pumps start at 12:01 hrs.
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