Potterton fault has the repairmen stumped!

[vmcd28]

We have a Potterton Performa boiler.

We have had Homeserve out 3 times already regarding this one problem, and theyve attempted various things - none of which have worked.

OK, so every day or two the "fault on pump or low system pressure" light indicator flashes. Eventually, the light goes off again and everything works fine. We did also have problems with the pressure falling, but that has been fixed.

Now, the bizarre part about all of this is that the warning light tends to flash if it has been a warm day and windows/back door have been open. It doesnt seem to do it in the winter, when the heating is constantly switched on.

The repairmen from Homeserve have tried replacing the timer switch on the kitchen wall (No idea why they thought that might work).
They have used a football pump to reinflate the pressure expansion valve (which fixed the problem with the reducing pressure).
The guy who reinflated the expansion valve said that it might need replaced rather than reinflated.

So, can anyone suggest what might be causing the light to flash? The pressure is fine, and doesnt drop.
Homeserve checked the pump and said it was fine, so they cant understand why the light flashes. Are they wrong - could it still be a problem with the pump - or could an issue with the pressure expansion valve be causing the light to flash?

Why do we only get this problem after doors and windows have been open? Could it be a thermostat problem instead?

Any suggestions would be great.

 

[Agile]

It may be a fault with the gas/combustion which we don't give DIY advice on.

But regardless, you have the maintenance contract so all you have to do is pester them until they sort it out. So there is no point in us discussing what might be wrong as it will not be you doing the repair. In any case the only place to identify faults is in front of the boiler.

But think along the lines that its the kind of firm who do not pay their staff very much, expect a lot of visits to be made every day and just simply will not have the best diagnostic engineers.

Then think that an independent will just not get paid unless he can correctly diagnose the fault. So they will usually be far better than those who have to work for those firms.

Tony

 

[vmcd28]

thanks for your reply. I get where you're coming from, but I hoped that someone could help on this thread, so I can tell them what could be wrong. It's getting tedious waiting in for repairmen who dont actually repair it!

I have just switched the boiler to Hot Water only, and the light didnt flash. It only flashes when it is set to Hot Water and Central Heating.

 

[Agile]

Bear in mind that you have a pretty cheap repair cover! So don't expect too much expertise fro them. Pay peanuts etc!

I don't think you would get far by telling them what you think is wrong. Some might even get annoyed and walk out.

As far as you are concerned they are the experts and you are not.

It used to annoy me but then I developed a few stock responses. The last of which is "so do you want to repair it yourself and I can leave?"

Tony

 

[vmcd28]

To be fair, they seem to have no clue, so far!

 

[bellairaphon]

Have they checked the differential pressure diaphragm?. It could be sticking.

Nath

 

[vmcd28]

I dont think they have, no - and could that cause the pump light to flash...?

 

[bellairaphon]

Yeah. That activates the microswitch to tell your boiler the pump is on.

Nath

 

[vmcd28]

hmm, thats really interesting - thanks v much!

 

[bellairaphon]

No worries, hope you get someone who will sort it for you.


Nath

 

[vmcd28]

Thanks again - I'm just baffled as to why it happens after windiws have been open! Strange.

 

[gas112]

Pump proving switch top of divertor , microswitch is either sticking or the pin is gunged up and not returning as quick as it should

 

[petit_pablo]

For such a basic fault, homeserve have excelled there

 

[Agile]

BG engineers I gather get £40k to £50k pa.

I would be surprised if Homeserve pay much more than £25k.

If that is so then obviously all the best engineers will be at BG and not at Homeserve.

 

[gas112]

Thats after the top 100 engineers who are all independents