Potterton Prima 80F suspected electrical problem?

[Vortex]

Hi There,

3 or 4 weeks ago my trusty 12 year old Prima 80F boiler stopped working. At the time I gave it a (small well calibrated) thump. It started working again and I thought no more of it.

Today it failed again. In the specific failure mode:

...The controls are calling for heat. ...The pump is running and the fan is on. ...The pilot light is lit ...but no main burner.

I took off the bottom cover and can see the gas valve is connected to the electrical control PCB/gubbins by a 4 way MOLEX style connector.

• If I carefully wiggle this connector the main burner lights straight away.

• If I turn down the temperature control it turns off the main burner as you would expect.

• When I turn up the temperature the boiler *sometimes* returns to the failure mode.

I sense a dodgy connection or a dry joint.

Q. Is this a common failure mode? Is there a specific connector or component that is the most common source of this problem. The benefit of your experience is appreciated!

David

[Ed Sirett]

You've found the fault. You might be able to make a repair with your soldering iron. I've seen this fault on similar models.

[Tim Lamb]

I had a similar fault on a Potterton profile.

The pc board connector pins had dry/cracked solder joints. As someone suggested, at the time, you need a magnifying glass to spot which pins need re-soldering. Go easy on the heat applied as softening the plastic part of the connector is very likely:-(

There was quite a long thread here last Christmas, but I think you already have the conclusions.

regards

[vortex2]

[snip]

Guys thanks for confirming my suspicions.

This morning I have unplugged and replugged all the connectors. Right now "it just works".

If/when it fails again I'll rework the solder joints.

Thanks again,

David.