Installation instructions geoTHERM VWS/VWW 0020051574_01
78
Fault code Error text/description
Emergency
mode
Possible cause
Solution
91
Brine pressure too low
Pressure <0.2 bar
Heat pump shuts down and
goes into operation automat-
ically when the pressure
rises above 0.4 bar
possible
Pressure drop in the heat source
system as a result of leakage or air
lock.
Check heat source system for leaks, top
up brine, bleed.
Brine pressure sensor defective.
Check the plug contact on the PCB and
the cable harness, check pressure sensor
for correct functioning, replace pressure
sensor.
L1 and N connections on the PCB in-
terchanged.
Check L1 and N connections on the PCB
and connect correctly if necessary.
94
Phase breakdown check fuse
One or more phases broken
down.
possible
Loss of a phase or a circuit breaker
has tripped.
Check circuit breakers and cable connec-
tions (power supply to the compressor).
Badly tightened electrical connec-
tions.
Check electrical connections.
Mains voltage too low.
Measure voltage at heat pump terminal
box.
Power company block on incorrectly
set E-plan (e.g. E-plan 1).
Check E-plan setting.
Start-up current limiter defective or
incorrectly connected.
Check start-up current limiter.
95
Wrong direction of rotation.
Change comp. phases
Phase sequence incorrect
possible
Phases switched over.
Change the phase sequence by switching
over 2 phases at a time on the mains
feed.
Start-up current limiter defective or
incorrectly connected.
Check start-up current limiter.
96
Error - sensor fault
Short-circuit in the pressure
sensor
possible
A pressure sensor in the coolant cir-
cuit is defective or not properly
plugged in.
Check the plug contact on the PCB and
the cable harness, check pressure sensor
for correct functioning, replace pressure
sensor.
Table 10.5 Fault-induced shutdown (cont.)
10.6 Other
errors/malfunctions
Malfunction sign
Possible cause
Solution
Noise in the heating circuit.
Air in the heating circuit.
Bleeding heating circuit.
Dirt in the heating circuit.
Flush the heating circuit.
"Out T. aux htr on" incorrectly set.
Change "Out T. aux htr on" (Menu A3).
Faulty pump.
Check functioning of the pump; replace if
necessary.
Traces of water beneath or next to the ap-
pliance.
The condensate drain is blocked.
Condensate in the interior of the unit is col-
lected in the condensate pan and, if neces-
sary, fed away under the unit (not a fault).
Check the insulation on the pipes in the inte-
rior of the unit and re-insulate, if necessary,
to reduce the accumulation of condensate.
Leaks from the heating circuit.
Check the heating circuit components
(pump, auxiliary heating, pipes) for leaks.
If necessary, retighten the screw couplings
and replace the seals.
Outside temperature indicates -60 ºC.
Outside temperature sensor defective.
Check outside temperature sensor.
Temperature in the heating circuit is too
cold or too warm.
Room target temp. not optimally set
Change room target temp. (Menu
1).
Set-back temp. not optimally set
Change set-back temp. (Menu 1).
Heating curve not optimally set.
Change heating curve (Menu C2).
Table 10.6 Other errors/malfunctions
10 Troubleshooting and diagnosis
