boiler fires with no demand gets hot trips few mins later fires again and so on cycle repeats

trencher, September 2009

most likely one of the microswitches on one of your motorised valves is sticking causing the boiler to fire, depending on the type you may be able to move it manually to free up the switch, but it will need replaced eventually. i could also be a faulty timer / thermostat but that's much less likely.

Ian, September 2009