Boiler pressure high - not expansion vessel or filling loop problem

[MezzaDM]

Hello,

I am looking for some advice. I had a high pressure problem with my Potterton Promax System 24 boiler. I assumed it was the expansion vessel which I replaced but the problem persisted. I then disconnected the filling loop to ensure it wasn't leakage from there causing the problem. The boiler pressure is still rising (3 Bar plus) and I am not sure what the problem is. My next guess would be that there is some kind of internal blockage and was considering flushing the boiler (although I wouldn't know how to do that).

Any help and advice most welcome.

M

 

[SimonG]

Could be pipe to expansion vessel blocked, but if pressure continuosly rising and you've already ruled out filling loop then I would say plate heat exchanger is split allowing mcw into htg side.

 

[Gray0689]

Could be pipe to expansion vessel blocked, but if pressure continuosly rising and you've already ruled out filling loop then I would say plate heat exchanger is split allowing mcw into htg side.

Agree with plate heat exchanger slit

 

[diesel_ltd]

what size is your expansion vessel is it possible its too small for the system??? how many rads?

 

[arran197]

Could be expansion vessel pipe is blocked.

 

[davi23]

Hi MezzaDm , I too have this problem did you ever get to the bottom of it,what costs were involved?

 

[SafeGasInstall]

min cost will be a visit from local heating engineer who can investigate the fault and then advise of the repair cost

 

[tms5725]

I would agree its either the plate hot water heat exchanger or a blocked pipe from the expansion vessel. I have had the latter problem a lot before. Mainly when the pipe to the exp vessel is of the braided flexible type. Vokeras seem to suffer from this a lot

 

[GrahamM]

davi23. The original poster made the mistake of changing what was probably a perfectly good part for nothing, due to their lack of knowledge.
Any half decent engineer would know how to confirm soundness of these these parts.
As safegasinstall advises have someone qualified look at it and save you a headache and throwing money away needlessly.

 

[wazzer]

My sister had a glow worm with this problem in the end it was the LH hydroblock leaking inside from CW to CH i was under guarantee so i didn't have to get involved

 

[mcniven]

I had this today, and it was the expansion vessel.

Water coming from the air screw valve at the top of expansion vessel. Changed it over, still doing it! Reason was the pipework to it was choked, so always best to clear that while your up there anyway!

 

[vipey]

hi if the heat exchange was split couldnt he open the hot tap and see if the pressure went back down as that would then take the pressure out ,