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Worcester 24cdi pressure loss

Discussion in 'Plumbing and Central Heating' started by Ben_M, 20 Sep 2007.

  1. Ben_M

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    Hi all,

    I have a problem with my 3 year old 24cdi which I think is diverter valve related. It has been dripping from the holes through which you can see the shiny steel shaft for a few years, not at a great rate so I put up with it. I have recently had my bathroom done, at which point a towel radiator was added and so the central heating pipes had to be moved. Since then the boiler has been steadily losing pressure - if I top it up to 1 bar it gradually loses the pressure over about a week.

    My first thought was that there is an external leak which is emptying the central heating system. However I have now topped it up from empty to 1 bar about 6-7 times, which is a lot of water, and there is no evidence of external leaking anywhere. I live in a 2nd floor flat and no-one from downstairs has complained yet.

    The other night I put the heating on for a few hours and since then it empties in about half an hour. I'm now in the position that I need to re-pressurise every time I need hot water. My question is this: is there any way a faulty diverter valve could be causing the pressure in the boiler to drop and empty the CH system? And if so where's it going?

    I have called Worcester service who are sending a plumber round on Monday, but of course I don't want to have to pay if the leak is external. I'm pretty sure it isn't, but I don't know enough about boilers to know if the water is going anywhere else!

    Any advice gratefully received.

    Thanks,

    Ben
     
  2. Softus

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    Does the system lose pressure if you don't run the CH?

    Have you checked the PRV?

    Have you checked the AAV?

    Have you checked all rad valves?
     
  3. Ben_M

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    The system loses pressure whatever happens. I haven't run the CH since the other night, and it still goes from 1 bar to empty in around an hour. Rad valves are all fine and dry. If AAV is automatic air valve, this is also fine - when the boiler is pressurised it vents as intended. I'm not sure where the PRV is.

    Even when the system is completely empty, the drip is still apparent from the diverter valve - collects about half a cupful a day. When the system is completely empty and the boiler is switched off there are ticking noises coming from the direction of the valve.
     
  4. Softus

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    You have to get the boiler leak fixed or else all bets are off. Once that's done you'll be able to home in on any other leak(s).

    The PRV is the valve from which a 15mm copper pipe leads through an outside wall - if you find the outlet and tap a plastic bag over the end you'll be able to tell if the PRV is leaking before the gas man cometh.
     
  5. Ben_M

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    Can't see any pipes going outside for the PRV - I'm in a 2nd floor attic flat and the boiler's mounted on a shared wall (its a terraced house). The flue goes through the roof but don't think there's any copper pipes going out there...

    I guess the boiler leak needs fixing anyway, so I'll see what the man says. I've just put the flat on the market - why does this always happen at the most inconvenient time?
     
  6. MTR

    MTR

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    Search for my very recent post about a nearly similar boiler. It may help.
     
  7. Ben_M

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    Just to follow this one up - the man from Worcester came round and replaced the diverter valve, PRV and AAV, external leak from boiler now fixed. Having turned off all the rad valves and isolated the CH from the boiler I have come to the conclusion that there is a leak in the CH pipework, more than likely for the towel radiator that I have just had fitted, as all the other pipework has been fine for 15 years. What a shame its just been buried under a new tiled floor.

    Thanks for the responses,

    Ben
     

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