System losing pressure

Discussion in 'Plumbing and Central Heating' started by Jever, 10 Jun 2018.

  1. Jever

    Jever

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    Hi all,

    I have a closed central heating system and the pipes to and from the radiators are run between the joists (upstairs) and under the screed (downstairs).

    The system usually runs at a pressure of 1 bar, but over the course of a couple of weeks, the pressure in the system slowly declines to zero.

    I assume there must be a leak somewhere, but I cant see any signs of it. If the upstairs pipes were leaking, surely there would be damp patches on my downstairs ceiling? If the downstairs pipes were leaking, wouldn't it show on the screed? I currently have bare screed and some of the rooms are tiled downstairs.

    Is there a smart way I can find out what's causing the loss in pressure?

    Thanks in advance for any help.

    Jever
     
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  3. Combicert

    Combicert

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    Go outside... there will be a small copper pipe sticking out of the wall from behind the boiler - it usually points back towards the wall... sort of like an inverted U shape

    Any water coming out of there?
     
  4. dilalio

    dilalio

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    Be aware that it could also be a holed hex and system water escaping down condensate drain. :notworthy:
     
  5. Combicert

    Combicert

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    Or expansion vessel issue... but, the water’s going somewhere...
     
  6. Jever

    Jever

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    Hi,

    The boiler is oil fired from the eighties. I've been outside, there are no pipes poking out of the wall. If I look behind the boiler, there's a pipe to and from, but nothing that would vent into a waste system.

    I had the closed system with a tank installed a couple of years ago. The plumber that did it put in a vent next to the tank (see photo attached), but I never see anything dripping there.

    Regards

    Jever
     

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  7. dilalio

    dilalio

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    Well it would have helped if you'd posted that in the first place :rolleyes:
    If the heating system is sealed then you will have a discharge pipe somewhere... Look for the expansion vessel and around that for PRV (plastic red top maybe) and discharge could go from that.

    Boiler and other components make and model and location of everything please...
     
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  8. Jever

    Jever

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    Hi,

    The boiler is a Myson Velaire, located downstairs. I think I've found the PRV(s) - see photos attached. The tank and everything else I've given photos of are upstairs in the bathroom.

    Items in these to photos are attached directly to the outlet I attached in the previous post.

    I never see any water flowing through the outlet, but I guess that doesn't necessarily mean it isn't going out that way.

    I assume the thing to do is to try to find a way to collect whatever might be flowing through the outlet?

    Jever
     

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  9. DIYnot Local

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