Vaillant geoTHERM VWS Installation Instructions Manual page 75

Fault code Error text/description
52 Sensors are not suited to
the hydraulic plan
60 Frost protection heat source
monitoring source outlet
Error 20 has occurred three
times in a row
62 Frost protection heat source
monitoring source outlet
Error 22 has occurred three
times in a row
72 Flow temperature too high
for underfloor heating
Flow temperature is higher
than a preset value for
15 min (max. HK temp. +
compr.hysteresis + 2 K)
(see Chap. 8.10, default
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
Error 28 has occurred three
times in a row
84 Coolant pressure outside
the range
Error 29 has occurred three
times in a row
90 Heating system pressure
too low
Pressure <0.5 bar
Heat pump shuts down and
goes into operation
automatically when the
pressure rises above 0.7 bar
Table 10.5 Fault-induced shutdown (cont.)
Installation instructions geoTHERM VWS 0020046310_01
Emergency
Possible cause
mode
_ Hydraulic plan not entered correctly,
sensors not connected correctly.
possible
See Error 20.
possible
See Error 22.
_ Flow sensor VF2 fitted too close to
the heat pump.
Flow sensor VF2 is defective
Defective heating circulation pump
or pump output has reduced.
Existing dirt strainers clogged or
incorrectly dimensioned.
Mixer behind buffer cylinder is
defective.
Max. HK temp. set too low.
possible
See Error 27.
possible
See Error 28.
possible
See Error 29.
_ Pressure drop in the heating system
as a result of leakage, air lock or
defective expansion vessel.
Screw couplings at the rear of the
heat pump are not sealing correctly.
Compression fittings on 3-way valve
are leaking.
Troubleshooting and diagnosis 10
Remedy
Check the hydraulic plan and sensor
positions using the existing system.
See Error 20.
See Error 22.
Relocate flow sensor in accordance with
hydraulic plan.
Check flow sensor VF2, replace if
necessary.
Test heating circulation pump, replace if
necessary.
Clean dirt strainers.
Test mixer, replace if necessary.
Check "Max. HK temp." setting.
See Error 27.
See Error 28.
See Error 29.
Check heating system for leaks, top up
water, bleed, check the expansion vessel.
Retighten screw couplings.
Retighten compression fittings on 3-way
valve.
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