Potterton SUrpima HE boiler - circulation fault strange one.

[kevinhumble]

Hello

I have had a new Potterton Surpima HE boiler installed under a year ago. We have a problem that has been happening since installation really.

When heating is on the boiler goes to lockout, often after having the boiler running for about 1/2 hour. The boiler manual fault light says it is a circulation problem.

My installer has tried everything, all air is out of the system, the bypass has been set properley, and he says the pump (which was already installed: Grundfos 15/50) should be OK as the fault does not happen immediately and only afte the boiler has been running for a period of time.

We have a 4 bed-house, an open vented system with 2 x 2 port motorised valves, a tank in the loft and a hot water cylinder in the airing cupboard.

What can be the problem please? Any ideas? My installer has now said it may be the board at fault, but the board was brnad new (part of the new boiler)?

Any ideas would be greatful, if I could try anything or even suggest anyything?

I suggested sludge may be trapped in the boiler, but he said it isn't that, and hot water seems to be fine anyway and that uses the same heat excahnger.

 

[Garfeild]

Has every radiator got a TRV on?

 

[kevinhumble]

yes, they all do. But the system has a bypass fitted.

 

[Happyplumber]

The boiler is under year old so still within the warranty period,why dont you give potterton a ring and they can send out the Heat Team who will check it out and confirm if its boiler fault or installation error

 

[MANDATE]

I don't think I would be satisfied with the pump, until it was removed and examined.
I had a circulation problem where the working pump could not be the problem. Well that was until it was removed and due to silt the input and output holes was reduced from about20mm down to about 7mm.
It could have been cleaned, but it was decided a new pump and isolation valves was a better option. Problem solved

 

[Mr Smyth]

Are the flow and return pipes between the boiler and the valves correct for the size of the Suprima.

Anything over a 70 requires 28mm pipework I believe.

Otherwise definitely suspect the pump.