Worcester Greenstar CDi 30 boiler - loss of pressure

Discussion in 'Plumbing and Central Heating' started by Crusader52, 5 Feb 2012.

  1. Crusader52

    Crusader52

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    I am having to re-pressurise the boiler every few days, although it does still work even though the pressure has dropped to near 0 bar.

    Can anyone advise how I can find out if the cause is a leak in the radiators / pipework, or a problem with the boiler itself?

    I have tried using Fernox to seal the leak, but it only works temporarily.
     
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  3. twgas

    twgas

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    check the discharge pipe, should be outside, often about 1m below the flue.
     
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  4. GasSafeTony

    GasSafeTony

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    Also could be discharging out of the pressure relief valve due to a faulty expansion vessel.
     
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  5. simond

    simond

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    That'll be the same thing, then.
     
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  6. Crusader52

    Crusader52

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    Thanks, will arrange a plumber to visit as I can't deal with boiler problems myself
     
  7. Crusader52

    Crusader52

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    I am having to re-pressurise every day now!

    I believe I have eliminated the pressure relief valve as the cause. I tied a bag to the discharge pipe 2 days ago, but it has remained totally dry.

    I have checked all the radiators and exposed pipework for leaks - nothing.

    There is no air in any of the rads.

    A brief visit from a plumber who was attending a neighbour also eliminated the expansion tank.

    That only leaves another boiler problem, or a pipe under the ground floor leaking - which is concrete! I have assumed this is less likely because the rads don't need bleeding (but this may be misguided)

    Any further ideas before I dig up the floors?
     
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  9. taz777

    taz777

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    I have the same boiler and had the same problem. Turned out to be a leak on a plastic compression elbow joint under the living room floor. Sadly, it is likely to be a leak somwhere. Get a good heating engineer or plumber to trace the fault.
     
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  10. Crusader52

    Crusader52

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    The pressure problem still persists, so I need to trace the fault. I was given some advice to close the flow and return valves to determine if the boiler is the source of the problem.

    If I do this, is it still OK to use the boiler for hot water, and should I also leave the CH 'on' (ie leave it to come on / off as programmed)?

    The boiler is a Worcester Greenstar CDi30
     
  11. ollski

    ollski

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    Turn the isolation valves off overnight before you go to bed, if your pressure has dropped when you wake up in the morning steel yourself for a new heat exchanger, I've done quite a few recently.
     
  12. I had exactley the same problem. Turned out to be a plastic isolator valve leaking under the ground floor. The valve (not fitted by me)fitted wasn't rated temp' wise for central heating, just domestic hot water..hence the valve seals leaking.
    I am only a diy plumber and the fault wasnt hard to find so give it a go yourself..you may save some money.
    If the leak is upstairs you would probably have noticed a wet patch somewhere on the ceilings.
    Lift some ground floor floorboards and have a peek. Look for anything leaking.
     
  13. Crusader52

    Crusader52

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    Update----

    My problem is now fixed. I called in a plumber to isolate the groundfloor rads, and after 2 weeks the pressure was still fine. As there was no sign of a leak downstairs, I had to assume the pipework in the concrete slab was leaking.

    For peace of mind I took the decision to have the downstairs rads replumbed from the first floor - I could have paid to trace and fix the leak, then find I had another one in the future.

    I took the opportunity to move a few rads at the same time and replace with new ones. Its all working now, and very cosy it is!

    Thanks again to all for their advice along the way.
     
  14. DIYnot Local

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