DIY Doctor UK DIY Forums

My Potterton combi 80 boiler provides hot water but when heating is called for, boiler fires up for 1-2 minutes then shuts down. Pump and fan are both running. This "on -off" cycle happens every 30 mins or so (if the boiler is on "constant" or on timer).
Please help! It's cold in Scotland.....

hi it sounds like it may be the C H temp thermsitor but to check it out the combustion cover needs to be removed but thats illegal for D I Y
and must only be attempted by a competant person so get a corgi engineer to look at it

Possibly diverter is stuck in HW mode, as there's no taps running the heat cannot escape therefore the boiler will keep cycling on and off.


htg