Boiler over pressure on the hot-water side?
how do I rectify the fault as detailed below?
No hot water, intermittent when air temp drops?
my vaillant boiler is saying a code com on it ?
how to fix water pressure its down at bottom of grey part?
Vaillant Thermocompact Fault?
Vaillant condensing boiler ecoTEC plus?
resetting thermostatat?
vaillant ecoTEC plus boiler fault code - how to fix?