Valiant thermostat , BMU-Err ?
Vaillant ecotec plus 630?
Vaillant vcw gb242 eh central heating problem?
Hot water supply?
Vaillant VCW-Sine18 T3WFH Lights but then goes off after 5 Min?
How can I fix my Vaillant turbomax 828 ??
my vaillant boiler is saying a code com on it ?
No hot water, intermittent when air temp drops?
how do I rectify the fault as detailed below?