Other Errors/Malfunctions - Vaillant geoTHERM VWS Installation Instructions Manual

10 Troubleshooting and diagnosis
Fault
Error text/description
code
91 Brine pressure too low
Pressure <0.2 bar
Heat pump shuts down and
goes into operation
automatically when the
pressure rises above 0.4 bar
96 Error, coolant pressure
sensor
short-circuit in the pressure
sensor
97 no power for compressor
Table 10.5 Fault-induced shutdown (cont.)
10.6

Other errors/malfunctions

Malfunction sign
The auxiliary heating does not function,
even though it has been enabled by the
controller (e.g. when the supply has been
blocked by the power supply company
(Power company blockage)); the heating or
the domestic hot water cylinder do not
reach the desired temperature.
Noise in the heating circuit.
Traces of water beneath or next to the
appliance.
Outside temperature indicates -60 ºC.
Temperatures in the heating circuit too cold
or too warm.
Table 10.6 Other errors/malfunctions
76
Emergency
Possible cause
mode
possible Pressure drop in the heat source
system as a result of leakage or air
lock.
Brine pressure sensor defective.
L1 and N connections on the PCB
interchanged.
possible A pressure sensor in the cooling
circuit is defective or not properly
plugged in.
possible Start-up current limiter defective or
incorrectly connected.
Possible cause
The auxiliary heating is tied to a low-rate
tariff which has been blocked by the power
company.
The safety thermostat (STB) on the auxiliary
heating has tripped.
Possible causes if the thermostat trips again:
Air in the heating system. Blocked dirt filters
in the heating system return line.
The heating circulation pump has stopped or
is running too slowly.
Air in the heating circuit.
Dirt in the heating circuit.
"Out T. aux htr on" incorrectly set.
Faulty pump.
The condensate drain is blocked.
Leaks from the heating circuit.
Outside temperature sensor defective.
Room target temp. not optimally set
Set-back temp. not optimally set
Heating curve not optimally set.
Remedy
Check heat source system for leaks, top
up brine, bleed.
Check the plug contact on the PCB and
the cable harness, check pressure
sensor for correct functioning, replace
pressure sensor.
Check L1 and N connections on the PCB
and connect correctly if necessary.
Check the plug contact on the PCB and
the cable harness, check pressure
sensor for correct functioning, replace
pressure sensor.
Check starting current limiter.
Remedy
Check whether the auxiliary heating is on a
low-rate tariff and a power company
blockage is in effect.
Release the STB by pushing the button.
Bleeding heating circuit. Clean the blocked
dirt filters.
check the heating circulation pump and
replace if necessary.
Bleeding heating circuit.
Flush the heating circuit.
Change "Out T. aux htr on" (Menu A3).
Check functioning of the pump; replace if
necessary.
Condensate in the interior of the unit is
collected in the condensate pan and, if
necessary, fed away under the unit (not a
fault). Check the insulation on the pipes in
the interior of the unit and re-insulate, if
necessary, to reduce the accumulation of
condensate.
Check the heating circuit components
(pump, auxiliary heating, pipes) for leaks.
If necessary, retighten the screw couplings
and replace the seals.
Check outside temperature sensor.
Change room target temp. (Menu
Change set-back temp. (Menu
Change heating curve (Menu C2).
Installation instructions geoTHERM VWS 0020046310_01
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