Fan has always been running even when no demand for HW or CH. Boiler fires up ok for both & sounds like the fan runs, but when they go off fan is stationary. Can hear faint singing like a kettle & temp gauge rises. Turning on HW tap seems to reduce this. Pilot stays lit. Had someone look at it but they said fan doesn't need to run all the time. I don't believe them!

Vic, December 2008

yes iain's right, the fan should slow run when no demand to stop the pilot from suffocating. Probably the boiler flow microswitch is broken, or there's a dry joint on the metalclad slow run dropper resistor, or the fan bearings are getting sticky. If the flow switch is bust it could be dangerous, as it might dry fire with no flow.

c, December 2008

pretty sure fan spins slowly on them due to permanent pilot when nothing is demanding.

iain, December 2008