Boiler pressure going down very slowly

Discussion in 'Plumbers' Talk' started by DIY Novice Simon, Jan 14, 2022.

  1. DIY Novice Simon

    DIY Novice Simon New Member

    We had a new CH combi boiler installed 4 months ago, corrosion inhibitor was added to the water and everything seemed to have been done correctly. I was away for about a month and noticed the boiler pressure was ever so slightly lower than when I left it. I went round all radiators checking for air, nothing until I got to the towel rail. A lot of air came out of it and then suddenly nothing - not even water came out. Checked the boiler and pressure was down to zero, so I refilled it slightly and it shot back up to 1 bar almost instantly. Got any small amount of air left in the towel rail out again until I got water coming out.

    Since then I have been monitoring the boiler pressure for the past few days and it looks like it’s dropping but so slightly that I don’t know if I’m worrying about nothing. At the start the pressure dial was on/just above the 1 bar mark and 3 days later it’s every so slightly below the 1 bar. I’m talking less than 1mm difference at the outer side of the dial. The attached photo shows the difference, both taken a few days apart after the boiler has not been switched on for a while.

    If there was a leak in the pipework, even a pinhole leak - would there be a much more noticeable drop? I have checked the radiators for any wet spots at the connections but haven’t found anything.

    Attached Files:

  2. terrymac

    terrymac Screwfix Select

    I wouldn't worry too much at present. Just monitor pressure ,if it continues to drop there is a problem.

Share This Page

  1. This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
    By continuing to use this site, you are consenting to our use of cookies.
    Dismiss Notice