Installation instructions geoTHERM VWS/VWW 0020051574_01
74
10.4 Temporary
shut-down
The compressor shuts down, the heat pump remains
in operation. The compressor can start again after
5 minutes at the soonest. (see below for exceptions).
Fault code Error text/description
Possible cause
Solution
20
Frost protection heat source
monitoring source outlet
Temperature difference at the
heat source (T3 - T8) > preset
value "Delta T. T3-T7"
This error message is deactivat-
ed as standard and can only be
activated via vrDIALOG parame-
ter "permitted temp. difference"
(20 K difference means deacti-
vated).
Heat source pump defective, temper-
ature sensor T8 or T3 defective.
Too low a volume flow in the brine
circuit.
No/full dirt filter in heat source re-
turn.
Air in brine circuit.
Check heat source flow rate.
Check the plug contact on the PCB and the cable
harness, check the sensor for correct position
and function (resistance measurement using
VR 11 characteristics, see Appendix), replace sen-
sor.
Check the volume flow of the brine pump (opti-
mum temp. difference approx. 3-5 K).
Fit/clean dirt filter.
Bleed the brine circuit.
21
(only VWW)
Frost protection heat source
over. source outlet
Source outlet temperature T8
too low (<4 ºC)
Temperature sensor T8 defective.
No/full dirt filter in source return.
Check temperature level of the heat source.
Check the plug contact on the PCB and the cable
harness, check the sensor for correct position
and function (resistance measurement using
VR 11 characteristics, see Appendix), replace sen-
sor.
Check the volume flow of the well pump/brine
pump (optimum temp. difference approx. 3-5 K).
Fit/clean dirt filter.
22
(only VWS)
Frost protection heat source
over. source outlet
Source outlet temperature T8
too low (< Freeze protect temp.
parameter in Menu A4)
Heat source pump defective, temper-
ature sensor T8 defective.
Too low a volume flow in the brine
circuit.
No/full dirt filter in heat source re-
turn.
Air in brine circuit.
Check heat source flow rate.
Check the plug contact on the PCB and the cable
harness, check the sensor for correct position
and function (resistance measurement using
VR 11 characteristics, see Appendix), replace sen-
sor.
Check the volume flow of the brine pump (opti-
mum temp. difference approx. 3-5 K).
Clean the filter
Bleed the brine circuit.
23
(only VWW)
No ground water flow
Integrated flow switch does not
detect any volume flow
Filter in heat source circuit blocked.
Well pump defective.
Motor protection switch on the well
pump has tripped.
Flow switch defective or not connect-
ed.
Clean the filter.
Check the functioning of the well pump, replace if
necessary.
Check for overloading, e.g. by blocking or a phase
missing.
Check the well pump, contactor and motor pro-
tection switch, replace if necessary.
Check the functioning of the flow switch.
Table 10.3 Temporary malfunctions
10 Troubleshooting and diagnosis
