Vaillant geoTHERM VWS Series, Installation Instructions Manual

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Installation instructions geoTHERM VWS/VWW 0020057444_01
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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 Remedy
20 Heat source outlet frost protec-
tion monitoring
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 "Delta T. T3-T7" (20 K differ-
ence means deactivated).
Heat source pump defective, temper-
ature sensor T8 or T3 defective.
Too low a volume flow in the heat
source circuit.
No/full dirt filter in source return line.
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 well pump/brine
pump (optimum temp. difference approx. 3-5 K).
Fit/clean dirt filter.
Bleed the brine circuit.
21
(VWW only) Heat source outlet frost protec-
tion monitoring
Source outlet temperature T8
too low (<4 ºC)
Temperature sensor T8 defective.
No/full dirt filter in source return line. 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
(VWS only) Heat source outlet frost protec-
tion monitoring
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 heat
source circuit.
No/full dirt filter in source return line.
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 well pump/brine
pump (optimum temp. difference approx. 3-5 K).
Clean the filter
Bleed the brine circuit.
23
(VWW only) No ground water flow
Integral flow switch not detect-
ing 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 diagnostics