The lights are on except for the flame light when demand is called for, but when demand is called for the boiler does not light. The flame ignition indicator light does not come on. I have no hot water or radiators. I had a new pump fitted about 18 months ago and am wondering if this has gone again. The plumber also replaced the diaphragm.

Mike Forrester, March 2007

Boiler fan and pump is running constantly even when no demand and I have hot water, but no heating

Pete, November 2007

I had the same problem - transpired it was an open circuit resistor on the mainboard PCB. Check to see if there isn't any scorching around R42 and the two plastic relays.

BobW, May 2007

poss ignition electrodes, air pressure switch, or check venturi tubes

hi-spec plumbing, March 2007