In message , a_mcbride
writes
I am wondering if there is anything in the safety system of a boiler
which would stop the pump before cutting off the gas. I cant think of
a reason why his would happen as it actually causes the overheat.

Could this be anything other than a problem with the PCB?

Could be the air pressure switch.

Andrew

Would this stop the pump without shutting off the gas burner?

I know I am harping on about it, but stopping the pump and not the
burner, causes an overheat, which seems crazy.

I suppose I should call Heatcall and see what order things happen with
it.

--
Richard Faulkner