Temporary Shut-Down - Vaillant geoTHERM VWS Installation Instructions Manual

10 Troubleshooting and diagnosis
10.4

Temporary shut-down

The compressor shuts down, the heat pump remains in
operation. The compressor can start again after 5 minu-
tes at the soonest. (see below for exceptions).
Fault code Error text/description
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
deactivated as standard and can
only be activated via vrDIALOG
parameter "permitted temp.
difference" (20 K difference
means deactivated).
22 Frost protection heat source
over. source outlet
Source outlet temperature T8
too low (< Freeze protect temp.
parameter in Menu A4)
Table 10.3 Temporary malfunctions
72
Possible cause
Heat source pump defective,
temperature 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.
Heat source pump defective,
temperature 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.
Remedy
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
sensor.
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.
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
sensor.
Check the volume flow of the well pump/brine
pump (optimum temp. difference approx. 3-5 K).
Clean the filter
Bleed the brine circuit.
Installation instructions geoTHERM VWS 0020046310_01