how do I rectify the fault as detailed below?
Valiant thermostat , BMU-Err ?
Vaillant eco plus 531 boiler?
how to fix water pressure its down at bottom of grey part?
What does f.25 mean?
Hot water comes and goes!?
resetting thermostatat?
Vaillant vcw gb242 eh central heating problem?
No hot water, intermittent when air temp drops?
vaillant ecoTEC plus boiler fault code - how to fix?
How can I fix my Vaillant turbomax 828 ??
Vaillant ecotec 831 plus?