Baxi 133 HE randomly firing up

[SPC]

Hi all, my friend has a baxi 133 he and it will randomly fire up at any time in the day. Any known faults with these boilers I should be looking out for?? I know it's on a honeywell timer which I'm going to disconnect first and just wire the boiler in directly. Hot water all works fine as and when it should. Just a heads up on a few things too look for would be nice. Thanx in advance

 

[Puddle]

Maybe hot water pre heat is on

 

[SPC]

Point noted, ill have a look. Don't know a great deal about these boilers.

 

[SPC]

Ahh I just thought, he said on the phone that it fires up, then shuts off and can sometimes fire up again after a few minutes, this happens day and night even if no water is being used, so would indicate it's not pre-heat function but I'll know a little more when I have a look later on.

 

[diesel_ltd]

if the flow switch on th hot water was faulty the boiler could try and fire up this is located behind the plate heat exchanger other than that i supose a faulty time clock

 

[Billy Bob Bob]

or sticking main ch flow switch,prone to this fault and as said dhw the same

 

[Toddyplumb]

No pre heat on 133. If not flow switch try frost protection stuck on , new PCB

 

[SPC]

I'm not sure on the flow switches. I disconnected the external time clock earlier and while I was there I noticed that when you shut the hot water off sometimes there was about a 30 sec delay until the burner went out then on other occasions it would go out within a couple of seconds of turning the tap off. This point too anything in particular? I didn't see any of the random fire ups while I was there.

 

[SPC]

right then ,update on this. ive disconnected the external programmer and that seems too have cured the rondom firing up ness. now the issue is when the hot water is ran 1 it doesnt get as hot as it used too, and 2 once shut off the boiler stays fired up for up to 5-10 mins or so. i got informed today that the boiler has had a similar problem for a long time, ie the rads were heating up when no heating was called for but running the hot water!! so sounds like there was a few faults. now im assuming it would be a divertor valve fault, think its best to get a replacement head???