Baxi 100 HE Plus cycles on and off all night

[John King]

Hi, I've a boiler that keeps going on and off without firing up. It's like some sort of cycle every 3-4 mins. We've set the heating to off (warmer weather now) but the hot water is on from early morning to late night.
It seems that if the boiler doesn't fire up for 2-3 hours (evening time) it starts this cycle of turning itself on every few minutes, like the pump starts turning but doesn't fire up?? This goes on all night!
Any ideas, suggestions, advice would be much appreciated.
Thanks

 

[Agile]

Is this heating a cylinder?

If so then you probably don't have the required 10+ degrees higher boiler temperature compared with the cylinder stat.

Tony

 

[John King]

There's a dial on boiler that I can turn up. I'll give that a try.
Thanks

 

[MeldrewsMate]

But Tony, if the boiler doesn't fire (as reported by OP) then there must be a fault in the system. Equally the OP has reported that the HW if OFF at night, but the noise goes on through the night...

OP, it would help if you gave the make and model of boiler, and other sailient info.
Is this a combi boiler? It could be, even if you have a HW cylinder....Is there a pre-heat switch? If there is ECO mode you could try turning this on....and all these suggestions depend on the make and model of boiler.
Do you have a timeswitch or programmer?
Do you have a room thermostat?
Post some photos?

All info can help us help you find a cure.

MM

 

[John King]

It was going on/off last night. Off for 3 mins then on for 1 min.

 

[Agile]

It seems that you may have a boiler fault.

Have you held in the reset button for about 12 seconds?

If that does not cure it then I expect that you will need a boiler engineer to diagnose the problem.

Might be a failed PCB.

Tony