Potterton Prima F won't fire up

[jakartakid]

Hi chaps, have a bit of a problem with my ageing Potterton Prima F boiler. It's about 10yrs old now and has worked fine until a few months ago. I started noticing that when the boiler was supposed to start for HW or CH, the fan would start then cut out after a few seconds, a few seconds later the same again, but the fan would go for slightly longer, this would happen for up to 10-15mins before the boiler would finally kick in and heat the water.
However lately, the boiler occasionally doesn't kick in at all, no matter how long I leave it....no hot water.
The plumber I usually use could not find the cause, but he is not a specialist in Potterton, going by the flow chart on the manual he suggests replacing the control panel as a first step.
Anybody out there had any experience of this and can help please?

Tim

 

[chrishutt]

Are you sure the fan is OK? I'd have a closer look at it. It could be running poorly / intermittently and not manage to trigger the air pressure switch. I'm sorry to question the competence of your plumber, but you haven't said if he is Corgi reg. and experienced in boiler fault finding.

 

[Agile]

I dont see many of these models.

Does anyone remember if the fan runs for ever if the APS does not switch?

Alternatively, and more likely, it sounds as if the flame detection is not operating, could be pilot, detection electrode or pcb!

I think it needs a boiler engineer rather than a plumber!

Tony Glazier

 

[jakartakid]

Sorry chaps, he is a Corgi heating engineer, I'm still living in the past refering to him as a 'plumber.' I think he checked the fan, I remember him checking the air-tightness of the case.
In the fault finding chart of the manual it goes.....

All services on.....yes

Call for heat.....yes

Does the fan run without cycling on/off.....no

Replace electronic control!

I would gladly have the electronic control replaced if this was your advice, I was just hoping somebody with experience of these boilers might be able to say....'Ah yes, that would be the *$+ that needs replacing.'

Thanks for the help so far.

Tim

 

[chrishutt]

Go with the fault finding advice, provided the checks have been carried out by a competent person (experienced fault finder).

 

[ollski]

Have a look at the flue outside and make sure it doesn't have a hole in it in the centre pipe...notorious for rotting through.

 

[ChrisR]

I'd want to be sure the fan was clean and the air switch was OK before buying a new pcb control. I have several of both by the way...