Combi boiler - pressure slowly increasing - is this correct?

helpingafriend

My mother has a Vailant combi boiler which is now about 3 years old, so far it has been ok apart from a slight panic when I over-filled it slightly when topping it up, but the pressure slowly came back down so that was ok.

A couple of months ago the BG man came out to service the boiler etc. When he was there he topped it up from 0.9 to 1.4, which is actually more than we had wanted, we have been trying not to exceed 1.2. The BG man was also supposed to check the radiators but he did not.

Since the BG man topped up the boiler, it seems that the pressure has been slowly increasing. It is now 1.6 although yesterday it 'flashed' to 1.7 then straight back to 1.6. The heating is not being used at present.

My mother is very worried about this in that there may be a leak or some other problem. I know nothing of plumbing or boilers at all. Any help that can be given would be gratefully received. Thank you.

musicmaker29

if the heating isnt being used then I dont see a reason why the pressure would be moving around that much - give the BG a guy a ring maybe and double check that everything is ok?? after all, he touched it last!

avantra

Ye, call Valiant and ask what is the recommended pressure for your model (should also be in the boiler documents), it will give you a starting point when you call BG.

helpingafriend

Thank you for your replies.

According to the manual, the recommended pressure is anything from 1.2 to 1.8 I believe and if it drops below 0.8 it will need topping up.

macman

I suspect that the stop valve on the top up loop was not properly closed, so it is continuing to pressurise. Either that or a bit of grit has got into the valve preventing it closing properly.
Sounds like a fairly typical BG service! Get them back to sort it and check the rads (if your service covered the latter and was not boiler only).

helpingafriend

Thank you everyone. Do I need to get a BG engineer out to check the top up loop or is this fairly easy to do myself? Basically, I don't want to do more harm than good!

Canucklehead

helpingafriend wrote: »

Thank you everyone. Do I need to get a BG engineer out to check the top up loop or is this fairly easy to do myself? Basically, I don't want to do more harm than good!

Good afternoon: does your mother have a BG 'Service Plan'? If yes, then she should call them to investigate the problem, after all that is why she is paying them every month.;)

HTH

Canucklehead

helpingafriend

I am pretty sure she does have this plan so I shall advise her to get a BG engineer out. Thank you everyone for all your help.

gas4you

Could be the BG man hasn't turned off the filling loop properly, or it could be a small hole in the plate heat exchanger, letting mains water through to the heating side.

This has been rather more common than one would like on Vaillants around the age of your mothers.

BG should sort it though.

macman

Since the pressure rise only commenced with BG's visit, my money is on the filling loop still being slightly open. OP, you can fix this yourself in about 5 seconds, but if BG have failed to do the rest of the job properly then you should get them back anyway.

john-306

They are supposed to remove the filling loop and put caps on, then this sort of problem wouldn't happen