Vaillant 0010002778, Installation Instructions Manual

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Installation instructions geoTHERM VWS/VWW 0020057444_01
Fault code Error text/description Possible cause Remedy
27 Coolant pressure too high
The integral high pressure switch
has tripped at 30 bar (g).
The heat pump can start again
after a 60 minute wait at the
earliest.
Heat consuming side using too little heat. Possible causes:
Air in the heating system. Bleed the heating system.
Defective heating pump or pump out-
put has reduced. Check pump, replace if necessary.
Radiator heating without low loss
header or buffer cylinder. Check the system.
Buffer cylinder, sensors VF1 and RF1
interchanged. Check the sensor positions.
Too low a volume flow as a result of
closing individual room controllers in
an underfloor heating system. Brief
heating operation occurs after every
DHW charge if the outside tempera-
ture falls below the outside temp.
switch-off limit! The control system
checks if heating operation is re-
quired. Check the system.
Domestic hot water cylinder with too
low a power input installed. Check power input.
Existing dirt strainers clogged or in-
correctly dimensioned. Clean dirt strainers.
Stop valves closed. Open all stop valves.
Coolant flow rate too low (e.g. ther-
mal expansion valve TEV incorrectly
adjusted or defective). Check coolant circuit.
28 Coolant pressure too low
The integral low pressure switch
has tripped at 1,25 bar (g).
Heat source providing too little heat. Possible causes:
(VWS only) Air in heat source circuit. Bleed the heat source circuit.
(VWS only) Brine pump defective or
pump output has reduced. Check brine pump.
(VWS only) Not all circuits are circu-
lating equally. Recognisable by differ-
ent degrees of icing on individual
brine circuits. Adjust the brine circuits.
Existing dirt strainers clogged or in-
correctly dimensioned. Clean dirt strainers.
Not all the required stop valves are
open. Open all stop valves.
Coolant flow rate too low (e.g. ther-
mal expansion valve TEV incorrectly
adjusted or defective). Check coolant circuit.
29 Coolant pressure outside speci-
fied range
If the error occurs twice in suc-
cession, the heat pump can start
again after a 60 minute wait at
the earliest.
Coolant pressure too high or too low,
all above-mentioned causes possible
Errors (27 and 28). See Errors 27 and 28.
Table 10.3 Temporary malfunctions (cont.)
Troubleshooting and diagnostics 10