Vaillant Vantage 120 Installation Instructions Manual page 33

Fault B:
Water discharging from expansion
relief valve.
Manually reset / seat expansion relief
valve. Is discharge still occuring?
Is the discharge occuring only when the
cylinder is being heated?
YES
Check pressure
charge in expansion
vessel.
OK
Exchange expansion
relief valve.
Fig. 17
Vaillant Vantage 120/150/200
YES
Reset pressure in
NOT OK
expansion vessel.
Does pressure hold?
YES
Is operation now
OK?
NO
YES
Fault remedied.
NO
NO
Turn off boiler and
NO
immersion heater. Is
discharge still occuring?
Is pressure downstream
NO YES
of pressure limiting valve
less than 3.5 bar?
Exchange pressure
limiting valve.
Exchange
expansion vessel.
Fault finding 11
YES
NO
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