Pilot lights fine but when i turn thermostat pump runs but nothing happens burner wont light, apart from the odd time you here gas valve clicking and it lights fine but only on the odd occasion. i am just new to fault finding is there any advice you can give me on what the problem is or how to find the fault. this happens on both heating and water and as always worked fine in the past. thanks.

Tony, June 2008

the odd time you hear the clicking and it lights is when its got through its sequence, if you only get pump the remainder of the time then you need to work from there.

generally, pump runs, fan runs, fan pressure closes circuit on air pressure switch (proving fan is running) then ignition and gas so see where it gets to, to find your fault.

so does fan spin?
if it does is it spinning freely?
are aps tubes clear and not brittle/broken?
is venturi in fan clear (where tube connects)?

iain, June 2008