Hope someone can shed some light..... For no reason today, my hot water and heating failed. The boiler (Potterton Kingfisher) fires up, although the temperature of the flue gases are much higher than normal, and runs for about a minute before shutting down - possibly overheating. The pump is ok (have removed and checked & only 3 months old), and if i push the (2 port Honeywell) motorised valve round with a screwdriver, the pump starts, although there is a sound like water cavitation as if it can't circulate at all. The wiring seems ok, but I am not sure where to go next. I haven't got a lot of money at the moment, so it would be good if someone could guide me as to where to go next. A plumber is the absolute last resort!
Thanks
Russell