Vaillant geoTHERM VWS Series Installation Instructions Manual page 73

Fault code Error text/description
60 Heat source outlet frost
protection monitoring
Error 20 occurred three
times in succession
61 Heat source outlet frost
VWW only protection monitoring
Error 21 occurred three
times in succession
62 Heat source outlet frost
VWS only protection monitoring
Error 22 occurred three
times in succession
63 No ground water flow
VWW only
Error 23 occurred three
times in succession
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 set-
ting: 52 °C)
81 Coolant pressure too high
Error 27 occurred three
times in succession
83 Coolant pressure too low.
Check heat source
Error 28 occurred three
times in succession
84 Coolant pressure outside
specified range
Error 29 occurred three
times in succession
90 Heating system pressure
too low
Pressure < 0.5 bar
Heat pump shuts down and
goes into operation auto-
matically when the pressure
rises above 0.7 bar
Table 10.4 Fault-induced shutdown (cont.)
Installation instructions geoTHERM VWS/VWW 0020057444_01
Emergency
Possible cause
mode
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 defective
Defective heating circulation pump
or pump output has reduced.
Existing dirt strainers clogged or in-
correctly dimensioned.
Mixer behind buffer cylinder is defec-
tive.
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 de-
fective 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 diagnostics 10
Remedy
See Error 20.
See Error 21.
See Error 22.
See Error 23.
Relocate flow sensor in accordance with
hydraulic plan.
Check flow sensor VF2, replace if neces-
sary.
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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