Pump/Low pressure warning

[BrendanS]

A friend of mine has had problems with a Potterton Performa System HE boiler. Pressure was down to zero, so I repressurised to 1bar. System started fine, with pump running, but after a period of time, warning light would flash again. If reset, it worked fine, but again, after a period of time, light would flash again. Pressure holds steady at 1bar when cold, and rises when hot.

She called a plumber out, and he said it might be failing pump, and went off to source/cost one.

However, he has now called back, and said he has spoken to Potterton, and it could be one of any number of faults, and he has suggested she call out a Potterton engineer at £299 + VAT (on top of the first plumbers call out charge), and costs of materials of course.

Is this a sensible course of action, or can anyone suggest some diagnostic tests to try to determine what the fault may be?

Thanks
Brendan

 

[Puddle]

Well think maybe plumber called out was not sure what problem was at all ,the boiler has a flow switch for pump so easy to see if flow ok
The two common faults that come to mind are fan air presure switch and possible faulty pcb
How long is boiler on before cuts out and goes to reset
If the £299+vat does not include materials you should be able to get repaired whatever if you get an engineer in who knows the boiler

 

[BrendanS]

I didn't time it when I was there, but at least quarter of an hour, possibly much longer. It certainly wasn't within a minute or two.

 

[Puddle]

Well I would go towards fan air presure switch but also check flue termination is clear
Ask them if they run hot water ,does it stay on the same time

 

[BrendanS]

OK, Thanks, I'll get her to time how long the warning light takes to come on with and without hot water running, and to check the flue. The pressure switch is beyond her capabilities though.

 

[BrendanS]

I haven't been able to get her to time it, as the warning light has not flashed since I've asked her to time it! Typical!

She has also got the list of possible causes that Potterton gave the first plumber

blockage in heat exchanger
filter on return clogged
diaphragm in ?something? valve
pump failure

 

[Puddle]

Alls well that ends well
It may have been air traped in pipework

 

[BrendanS]

Sadly not!

Received this email from her this morning

"so....then I decided to set the timer to heat the water this morning. Checked at 7am and light was flashing, so put the immersion on to ensure I had enough water for shower. When I checked at 8am the light had stopped flashing. I had wondered if there was a link between the immersion having been on and therefore the water already hot and the boiler not flashing. But I'm not sure what that says about the problem."