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Help! Valiant combi boiler pressure dropping…

Discussion in 'Plumbing and Central Heating' started by Christian70, 29 Jul 2021.

  1. Christian70

    Christian70

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    Hi,

    I need advice, my Valiant combi boiler, which is about 8 years old, pressure keeps falling day by day. I have had the Expansion Vessel replaced and PRV replaced, anti-leak stuff put into the system. Nothing has helped! There’s no signs of water or leaks anywhere. There are no pipes under the ground for or embedded in the walls. I even got a leak locator guy out who couldn’t find anything either or anything wrong with the boiler.
    I’m at my wits end with it! Please help!
     
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  3. muggles

    muggles

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    Turn the boiler off, and redirect the condensate into a bucket, then repressurise the boiler. If the bucket fills up, your main heat exchanger has failed
     
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  4. Christian70

    Christian70

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    Thanks! I’ll have to get a plumber to that for me as I’m disabled.
    I don’t if it would be the Heat Exchanger, wouldn’t that affect the hot water too?
     
  5. ianmcd

    ianmcd

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    yes good chance it is the main heat exchanger
     
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  6. CBW

    CBW

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    Does the pressure increase at all, or just drop? Has it been isolated from the heating system?
     
  7. Christian70

    Christian70

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    The pressure just drops. No, I don’t think my usual plumber isolated it from the heating.
     
  8. CBW

    CBW

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    It might be a worthwhile exercise to rule out certain factors.
     
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