"John Stumbles" wrote in message
...
Phillip Brown wrote:
Is it possible the fan could be faulty, or is there some other
possibility between the timer (which works as it too turns the pump and
valve on and off) and the boiler?

Is there mains getting to the boiler? Sometimes there is just one mains
cable to the boiler which is made live when there's demand via the
programmer + room 'stat + motorised valve, sometimes there is a live feed
via a fused spur and a separate switched live via prog + stat + valve.
Either way if the live is getting switched on and off with the room stat +
valve (test with a neon screwdriver) but the fan's not starting it
suggests the fan is kaput, but if there's no switched live you've got an
electrical problem.

Thanks John, there is no other fuse, the cable chain is as follows AFAIK:

Mains box with fuse Wall thermostat Timer / Pump / Valve Boiler

When I turn on the timer with the thermostat up, it starts the valve opening
and pump running. I can see the cable running out of the timer which goes
all the way in to the boiler.

What part of the cable would I prod with a neon screwdriver to check the
live is getting to the boiler?

Could it not be the PCB on the boiler itself?

Thanks again.