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Pressure droping on central heating issue

Postby bra1ne » Wed Mar 16, 2011 3:56 pm

I am having a bit of a problem with BG sorting out a central heating issue. Our bolier keeps losing pressure and drops within 20 minutes from apprx 2 bar to about 0.5-0.8 bar. Once at approx 0.5 bar is stays there constantly.

The engineer stated it was a definite leak but only very small and its OK and bolier will work OK at low pressure. We have a fairly large 3 story house (shared) and also cant see how a litre of water disappearing in 15-20 minutes is a "small leak". I can see no visable leaks around radiators in in our ceilings and have checked the cellar, the only pipes I cant see our ones which go under the kitchen floor to the boiler and off to the bedroom next to the kitchen.

There is also no water leaking from the overspill from the expansion tank.

The central heating side of our system is not covered for pipe leaks but I do have plumb and drainage cover (which in T&C's state central heating pipes if water leaking) so have a plumber due out Friday. I am converned they are going to turn around and say its not something he can do but is a central heating/bolier issue and I am going to go round in circles trying to get issue resolved!

Can anyone offer any advise (besides not to use BG as I already have paid for cover so expect them to complete the job!!) ?
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Simply Build It

Postby htg engineer » Sat Mar 19, 2011 8:13 pm

Sorry I know you specifically said not to, but............... stop using BG.

Stop paying for their cover - waste of time - as you're experiencing.

Turn off mains electric supply to boiler, so CH and HW cannot be used - Pressurise to 1.5bar and turn off the flow and return isolation valves - leave for as long as you can - go to work etc.

Get back from work and check pressure still at 1.5 bar ? rules out PRV leaks from boiler etc. Open flow and return isolation valves, if pressure has been lost throughout the day via a leak on pipework/radiators - pressure on gauge will drop immediately.

Still at 1.5 bar ? then it probably is the expansion vessel.

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