Halstead combi boiler pressure

9 Oct 2008
Reaction score
West Glamorgan
United Kingdom
Hi, we have been having problems with our Halstead combi boiler, the central heating works O.K but the hot water go's cold after a few seconds. There is hot water coming out from an overflow pipe outside the house below where the boiler is and the pressure is showing 2.5 to 2.9 bar. Can anyone advise us on how to lower the pressure without an expensive plumber callout.

Cheers in advance for any advice given.
Sponsored Links
if pressure stays high all the time I would suspect the filling loop turned on slightly or letting by, if pressure rises when boiler heating would suspect the expasion vessel needs recharging/replacing.

hot water fault could well be muck in secondary h/ex - caused by fresh water being continuously introduced to the boiler
Sponsored Links
And to lower the pressure, just bleed a radiator. There should be an increase of about 1 bar, between CH cold and CH hot. If pressure exceeds about 3 bar then the 'pressure relief valve' will open. I guess this has happened in your case.

DIYnot Local

Staff member

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.

Are you a trade or supplier? You can create your listing free at DIYnot Local