Technical data

11 Fault finding
Vaillant Vantage 120/150/20032
VIH_Fault_A
Fig. 16
The water from the cylinder is cold.
Does boiler operate?
Do external controls
function?
Remedy fault
according to boiler
instructions.
Remedy fault
according to controls
instructions.
Is 3-port valve in
corect position? (Mid
or DHW position).
Does cylinder
thermostat operate?
Replace cylinder
thermostat.
Vent heating coil of
air (H, fig. 4).
Check/replace
3-port valve.
Is operation now
OK?
Fault remedied.
NO
NO
YES
YES
NO NO
YESYES
YES
NO
11 Fault finding
Note:
Only genuine spare parts supplied
by Vaillant Limited must be used.
Fault A:
VIH_Fault_A