Potterton Performa 28 aps or pcb?

[paulmag]

I've got an intermintant fault on the boiler. It will usually start from cold but not always and the same is true on automatic restarts after it reaches operating temperature.
When it fails the fan starts but stops approx 5 times and then I get a fan failure light. The aps looks good the tube are in new condition but I wonder how to check it electrically. I get mains voltage on the contacts which then disappears as the fan cuts out.
Looking at the forum people seem to be 50-50 on whether its an aps or pcb fault.
Any ideas on how I can narrow it down any further.
Thanks in advance

 

[Agile]

I cannot give you advice on the APS as thats CORGI territory.

But I have heard of PCB faults like that on your model but not seen them myself.

Tony

 

[bengasman]

Does the boiler lock out under certain conditions or completely at random?

 

[paulmag]

Hi

Can't see any pattern. Starting from cold, it can light first time or take up to 4 goes.
Obviously, I don't know how many times it re-ignites successfully once it reaches operating temperature.
I'm kinda thinking intermittant faults likely to be flaky electronics- the pcb- rather than a pressure switch. The switch looks pretty simple and again I'm thinking it should work or not work. But I don't know.

 

[bengasman]

I agree with Tony on the aps side. I have seen several pcb problems on these though. this model seems also to be quite sensitive to the quality of the electrical supply, could be worth checking if there is a voltage between neutral and earth, and the quality of the earth. You need specialist equipment for the latter though and I would not recommend diy on electrics any more than on gas.

 

[paulmag]

Thanks for the advice I think £150 to BG might be the best bet then

 

[ChrisR]

Well yes, that'll be about the most expensive option, but should work!

 

[paulmag]

@ChrisR

I made some calls to a few companies and they had said £80 for the first hour and £40 per half hour after that. This wouldn't include parts whereas BG say that £150 covers parts and labour regardless. Am I missing something in this? Any advice gratefully received

Thanks

 

[ChrisR]

I'd suspect the aps (easy for us to test) which is about £25. And I should obviously put my rates up!

You might be really lucky, like these chaps:
http://forums.moneysavingexpert.com/showthread.html?t=630759

BG are currently advertising £198, and it's not available in all areas.

 

[paulmag]

ok thanks for that chrisR. When I put a voltmeter across the switch it looks as if it voltage to it when the fan first kicks in then as the fan powers down the voltage drops any other way I can prove if the switch works?

 

[ChrisR]

The voltage from it would be a better guide, and it depends exactly when...

 

[paulmag]

Thanks for that.
The switch has three terminals. Blue and brown wires and then a black wire at the side. I assumed the blue/brown are the supply and the black is the output. What do you reckon?

 

[paulmag]

I checked BG website and they are quoting £156 to come out and fix the fault. APS is £15 when ordered online PCB is £90 approx online.

 

[weareleeds]

The three connections are common, normally open & normally closed. The pcb checks state of aps on demand & if it has stuck in closed position it will not allow fan to run

 

[paulmag]

well bit the bullet and have arranged for BG to come out and fix my boiler. £156 to fix it all parts and labour included so hopefully that will be the end of my worries although not holding my breath. Will post back with the results. Thanks to everyone for their time and experience.