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Expansion Vessel Advice

Discussion in 'Plumbing and Central Heating' started by Muzz, 7 Aug 2013.

  1. Muzz

    Muzz

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    Hi,

    I noticed the pressure in my CH system is dropping. On closer inspection I see the pressure goes up to near 3bar and the PRV starts weeping. I have an external vessel. Boiler is a Worcester greenstar 24ri (might be a lower number, I can't remember right now).

    I read the guide on how to recharge the vessel so thought I would try that.

    With about 0.7bar in the system I pressed the valve and no air came out, released the system pressure through a drain cock, then tried pressing the valve and some air came out, pumped it up a bit tried the valve and air came out, no water came out.

    After pumping more air in I notice the reading on my pump slowly falls, pumping air in then trying a push on pressure gauge doesn't even register on it.

    Is it possible for the vessel to be faulty and for no water to come out when the system is pressurised?

    The PRV only seemed to leak under higher pressure will it need replaced anyway?

    Thanks,
     
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  3. dcawkwell

    dcawkwell

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    drop the pressure and leave the drain valve open.
    Pump the vessel up to 1 bar. Remove the pump and then test it with a quality tyre gauge.
    Leave it an hour or so and retest it. If the pressure in the expansion vessel has dropped it's leaking. You might want to test the actual tyre valve with a little washing up liquid to see if the valve itself is leaking.
     
  4. Muzz

    Muzz

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    got it pumped up, i think i was just being over cautious in the amount of air i was putting in. Pressure seems to be holding too.

    prv is weeping now even at normal system pressure so I'll swap that out.

    what is the purpose of the adjustable red line on the prv is that set to the minimum system pressure i should have?

    cheers,
     
  5. dcawkwell

    dcawkwell

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    If the pressure relief valve is a twist type give it a few twists and it should seat. The give it a week. They can seat again.
     
  6. Boilerman2

    Boilerman2

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    What's wrong with a bit of spit dabbed onto the valve??? :confused:
     
  7. dcawkwell

    dcawkwell

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    Spitting on the value isn't really a quality service is it?
    One has to be seen to do a quality job and there is always washing up liquid available.
     
  8. Agile

    Agile

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    Spit is not the approved leak detection fluid which should be used on boilers!

    It comes in a bottle and costs about £3.

    Spit is free and the merchant makes nothing from that!
     
  9. DIYnot Local

    DIYnot Local

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