Boiler 3 yrs old. At the end the heating cycle there is about 8-10 clicking sounds in say 10 secs with the fan starting and stopping each time. The same happens when the boiler is asked to fire-up again. Whilst heating it is ok until the next off period. I have changed the temp sensor but no different. Will it be the pcb or just a pressure switch etc? Thanks

Alan G, February 2007

I had exactly the same problem.
Checked all power into boiler = ok
Checked the overstat was ok, fan running, sucked on the pressure tube to see if the pressure switch was ok, measure fan flue temp = ok
Fired boiler up and the clicking eventually started again.
Removed the boiler thermostat carefully and almost immediately the boiler fired up correctly.
Therefore suspected the pcb - found "live" 240V ac all over the board included tops of the electrolytic capacitors !
This didn't seem correct so ordered new pcb for £55 and fitted it - success !

Ray Crossman, February 2011

pcb contactor breaking down you will require a new unit complete its on a printed circuit board.

Pete, May 2010

Did you ever get an answer to this question or find the solution yourself? I am getting the same clicking noises with my Potterton Kingfisher MF.

Darren, September 2007

Did you ever get an answer to this question or find the solution yourself? I am getting the same clicking noises with my Potterton Kingfisher MF.

Darren, September 2007