My Vaillant combi boiler provides hot water but the Ravenheat transmitter type thermostat has stopped working so that the central heating does not work at all. Transmitter unit batteries have sufficient power but the mains powered receiver unit is not illuminated as to either its blue light (working) or the red light (R/F failed). Any suggestions would be welcomed.

John in Sheffield, May 2013

you may need to reprog it,i had same prob the idiot instead of swoitching the boiler off by the on off button oin boiler ,turned it if by the isolating switch,this cancelled the prog so the theremostat had to be reprog

mm, May 2013