Hi Geoff/Ed

Thanks for the replies.

Geoff - No clicking , Pilot is on, pump and valve work fine. Just
pumping cold water around.

Ed - Don't know about the heating of the phial, but the boiler does
fire up initially but dies again after a few minutes.

Thing is it was working fine all week. I bled the radiators this
morning, there was a little bit of air in one, about 5 seconds worth,
but nothing major. One thing I noticed is that it does get awfully hot
to the touch. I know that it would get a little hot, but not sure how
hot they are meant to get. I cannot touch it sometimes. The fan works
fine.

The other thing I notoiced today is that if I drop the PCB mouting
plate from the front and let air flow freely through it worked fine for
a few hours. Have put it back on timer and left it open tonite to see
if it works OK in the morning. Could this be a dry joint or a problem
with the trip switch?