I have a Potterton Kingfisher Boiler which has a intermittent problem, which is causing the tank to bubble overheat, I have had the heat control valve changed, but still has the same problem. The PCB is also clicking? could this be the fault.

John, April 2014

need good clean up ,feed pipe is near blocked ,pour good cleaner in head tank run for few days than flush out ,drain out with air vent on rads open for two time ,close air vents when filling ,open big nut on open when filling each time, or power flush bit costly

ltd, April 2014