baxi 105e instant switches on and off

[really60]

hello. i have a baxi 105e instant combi boiler.

the boiler is not used much at the moment (hot weather) and so it is only used for hot water. the 'instant' part (preheat) is off - i don't need a tank of hot water waiting to be used.

recently, at various times, the boiler has been trying to start. the water indicator light comes on, the water pump and the fan starts to turn and then they all turn off. they then all come on again and off again and continue to behave this way. it happens at a rate of about once a second.

to stop the process (without completely turning everything off) i have to turn the heating on. when i do this both the water and heating lights take it in turn to go on and off but eventually the system settles down and only the heating light stays on.

i can then turn the heating off and all is ok for a while - sometimes a long while, sometimes not. if though, i need hot water, the problem tends to return quite quickly. often, as soon as i turn the hot water tap off, the boiler will start this on/off cycle.

any ideas anyone?

 

[Murf520970]

could be a leaking cold tap leaking just enough to trigger the boiler, thats a long shot, also a sticking microswitch on the water pressure differential assembly, or the preheat kicking in incorrectly , baxipotti or agile will know more