Potterton Performa 24 cutting out and waiting to restart

[bazray]

Hi (great forum by the way), my boiler had a problem where the hot water was calling constantly but i managed to fix it by changing the microswitch. It has now developed a further problem where it fires up but after about 20 mins the flame goes out, I can still hear the fan and the thermostat is on full for both water and heating (I have tried it on lower too) I have also tried the same on just water setting too. I thought it might be the temp sensor so I took a cold reading and it was 11K ohms which is fine then I ran the boiler until it cut out and the reading was 4K ohms (is that about normal?).

I have to wait quite a while before it will fire up again (30 mins+)

One thing that is strange is that when it cuts out or if I turn the thermostat down it wont fire up if I turn it back up but the fan still goes.

Any suggestions or further tests would be much appreciated. Thanks

 

[bazray]

Any ideas or suggestions much appreciated..

 

[twgas]

Do you have about 1 bar of pressure in the heating system?

 

[bazray]

Yeah its about 1.1 I would say, I topped it up to 1.5 and tried that, then dropped down to 0.8 ish . It fires occaidionally and seams to work best when very cold ie first ting in the morning I have no idea why. I never get a fault light or safety stat reset.

Its hard as it intermittent. I did notice the pump get hot to the touch but perhaps thats normal, if the pump is on its way out would the drop in flow cause it do not to spark?

 

[Agile]

I have an idea of what might be at fault but as thats gas related I cannot mention it on an open forum.

You may end up having to call an engineer.

Tony

 

[kevplumb]

I have an idea of what might be at fault but as thats gas related I cannot mention it on an open forum.

You may end up having to call an engineer.

Tony

so what was the point of the post then numbers getting down

 

[Agile]

It will hopefully encourage him to call a professional.

Or if he is a bit naughty then it would point him in the possible direction of the fault.

But there is only one effective way to diagnose a boiler fault and thats from in front of it.

Tony

 

[bazray]

Yeah I'm not going to tinker with any gas parts. I'm just trying all the possible elimination fault finding I can do.

I checked the gas meter lever was fully open, and also when the boiler last fired up i ran the cooker to see if had any effect on the flame.

 

[bazray]

Well I took a gamble and bought a pcb on ebay for £20. All is working perfectly now

It looks like R73 got cooked when the hw microswitch was stuck on.

I'm going to get it serviced and get boiler insurance too, whats the best value? I have been looking at british gas and swinton insurance.

Any suggestion appreciated.

 

[adlplumbing]

bg are proably cheapest but to be ware they out to sell you stuff you may not need
thats not dig at their engineers but culture they have to work under