DIY Doctor

Main navigation

Pressure drop, ch only, corgi eng had no idea...

Postby loumo » Tue Dec 23, 2008 1:24 pm

We bought this house 6mths ago. Didn't use the heating till autumn. Turned it on and found a small leak in one of the pipes right at the boiler. Turned it off, made an appt with a corgi reg engineer. He came, switched it on and there was no leak. For his fee, he bled all my heaters for me! He topped up the system pressure, left it on for half an hour then left me to it. That was ten weeks ago, it's been fine since.

Yesterday, we had the heating on and noticed the pressure had dropped and a few rads had air in. We bled them, topped up the system pressure, and when we put the ch on again, the pressure dropped again. There is no problem with the hot water, no system noises. Our boiler is a worcester 24i junior, there is no water tank. Most of the rads have trvs. There is no noticeable leak any where obvious, including where it was before. Our outlet pipe thingy for excess water (that is used for pressure relief) was blocked before but the guy fixed it. I have not yet checked if it is dripping.

Problems: the boiler has been boxed in by the wall, and I can't get it open - neither could he. The pressure relief button or whatever is incredibly hard to reach for this reason. I live in a flat and don't want to flood my neighbours at this time of year by messing about with it, and we cannot locate a stopcock anywhere on the property (have checked neighbours' flats and ours is not where theirs is - last owner fancied himself as a handyman.) and the engineer I already called out had no idea what caused the problem. I don't really fancy paying another huge sum to have a different guy come out and tell me he can't do anything, or start pulling stuff up before Christmas...

Has anyone got any ideas what I can do to try to get it sorted? The pressure has dropped completely over ten weeks, then by 0.5 bar over about 4hrs this likely to be a big leak somewhere, or venting to outside?

I don't even know what the right questions are to ask, so any wisdom would be much appreciated!

Rank: Labourer
Progress to next rank:
Posts: 1
Joined: Tue Dec 23, 2008 1:11 pm


Simply Build It

Postby htg engineer » Tue Dec 23, 2008 8:33 pm

Losing 1.5bar over 10 weeks it wont be a huge leak. Adding leak sealer to the system may solve the problem. However I would only use leak sealer as a last resort as it can also block radiator vents and auto-airvents (although not a huge problem).

Check everywhere accessible for leaks, boiler, radiators, valves, pipework, PRV discharge etc etc. It's up to you if you want to start lifting floorboards etc - best to if possible. If no luck finding a leak - add leak sealer and see if it works.

As for the boiler not being accessible - how will it be serviced and repaired ? get the installer back.

Also its worth checking the pressure doesn't rise too much with the CH on, and make sure the combi fill is disconnected.

htg engineer
Rank: Project Manager
Posts: 3256
Joined: Tue May 22, 2007 5:22 pm

Display posts from previous
Sort by
Order by

  • DIY How to Project Guides
  • DIY how to tutorial projects and guides - Did you know we have a DIY Projects section? Well, if no, then we certainly do! Within this area of our site have literally hundreds of how-to guides and tutorials that cover a huge range of home improvement tasks. Each page also comes with pictures and a video to make completing those jobs even easier!

  • Related Topics