Vaillant geoTHERM Installation Instructions Manual page 104

11 Fault diagnosis and rectification
Fault code Error text/description
52 Sensors do not match the
hydraulic scheme
60 Heat source frost protect
monitoring source outlet
Error 20 has occurred
three times in a row
61 Heat source frost protect
(VWW only) monitoring source outlet
Fault 21 has occurred
three times in succession.
62 Heat source frost protect
(VWS only) monitoring source outlet
Error 22 has occurred
three times in a row
63 No ground water flow
(VWW only)
Fault 23 has occurred
three times in succession.
72 Flow temperature too high
for underfloor heating
Flow temperature higher
than set value for 15 min.
(max. CH temperature +
compressor hysteresis +
2 K) ¬ Ch. 9.8,, factory
setting: 52 °C).
81 Coolant pressure too high
Error 27 has occurred
three times in a row
83 Coolant pressure too low.
Check heat source
Fault 28 has occurred
three times in succession
11.4 Fault with permanent switch-off
104
Emergency
Possible cause
mode
_ Hydraulics diagram incorrectly
inputted. Sensors not connected
correctly.
possible
See Error 20.
possible
See Error 21.
possible
See Error 22.
possible
See Error 23.
_ Flow sensor VF2 fitted too close
to the heat pump.
Flow sensor VF2 is faulty
Pump output of the external
heating circuit pump has dropped
or pump is faulty.
Existing dirt strainers clogged or
incorrectly dimensioned.
Mixer behind buffer tank is faulty.
Max. CH temperature set too low.
possible
See Error 27.
possible
See Error 28.
Solution
> Check the hydraulics diagram and
sensor positions based on the existing
heating system.
See Error 20.
See Error 21.
See Error 22.
See Error 23.
> Change the position of the flow sen-
sor according to the hydraulics dia-
gram.
> Check flow sensor VF2, replace if nec-
essary.
> Check the external heating circuit
pump, and replace if necessary.
> Clean dirt strainers.
> Test mixer, replace if necessary.
> Check "Max. CH temp." setting.
See Error 27.
See Error 28.
Installation instructions geoTHERM 0020051574_04