Potterton Puma 80e

[vic11]

Hi all

Intermittant fault in that it will not fire up. It can be working fine the night before but when its due to come on again (on timer or manually) it doesn't.
The power light is on and you can hear and see one of the relays click and the fan starts but thats it. The green light doesn't come on. No heating or hot water. It can happen whether you just want heating or hot water or both. Have noticed that if you switch between <Constant> and <Timer> on the <Central Heating> switch the green light comes on for a split second. Eventually the heating will come on. It could be a few minutes or several hours but then it works fine.

Thanks for any advice
vic11

 

[Agile]

You have not said anything about hot water delivery!

Tony

 

[vic11]

Agile,

I think I have

 

[Agile]

Sorry so you did, I was speed reading it too fast and you were concentrating on the heating aspects whereas the problem affects both equally.

Unfortunately its likely to be a gas/combustion related issue on which we do not give advice for DIY repairs.

Although it could be an ignition PCB fault, it would not be adviseable to replace that until the other possibilities have been eliminated first.

So the advice would be to engage a competent gas reg engineer who is familiar with that model to diagnose the problem.

Tony

 

[vic11]

Ok Tony thank you for your advice

Vic11

 

[vic11]

Tony (or anyone else)

Just to update you.

Wife showered yesterday and it was fine. I go in, get wet and the bloody thing turns off. It then turns on and off a few times before it eventually stays on.

Heating had turned off this morning before the set time on the timer.

What I have noticed is that on the modulator board, the first relay at top left clicks when its calling for hot water or heating. The relay next to it clicks when it fires up ok but does not click when it doesn't fire up.

A small area of the plastic on the first relay also looks dark and you can hear a faint fizzing noise coming from around the board. Like arching.

Like to add that just after the warranty ran out we had problems with several dry joints on the board which I then re-soldered and corrected the fault.

vic11

 

[Agile]

Its common for the plastic case on relays to become darkened by arcing on the contacts. That does not mean its not working.

Fizing sounds would usually be arcing somewhere although that can be on relay contacts although that would usually be seen in the dark.

I dont understand if you mean that you have got it to work again by resoldering joints on the main PCB.

Tony

 

[vic11]

Sorry Tony maybe I didn't make it clear.

The re-soldering of some of the dry joints refer to problems with the boiler many years ago not recently. Touching certain areas on the board and the boiler would fire up. It was just a light tap which was enough to make contact. Having a closer look revealed bad contacts so these were re-soldered which solved the problem.

Vic

 

[vic11]

Tony,

Just to give you a final update which is to let you know its working fine.....touch wood.

It was dry joint on the back of the Modulator board hence the fizzing sound (arching).

If you undo the four screws holding it and lay it down (still connected but electric off) it was the "L" shaped joint about a third of the way down on the left hand side. There are four inline joints and one to the right of those.

Anyway up till now its been going without any problems so something to add to your list of possibilities for future troubleshooting.

Thank you for your advice and help
Kind regards
Vic