Worcester Greenstar Boiler losing pressure

Discussion in 'Plumbers' Talk' started by fazse, Nov 8, 2018.

  1. fazse

    fazse New Member

    Hi everyone, need a little help. I have read other threads about losing pressure and done some checks but my particular problem is not mentioned on previous posts.

    I’ve bought a house and noticed the boiler is losing pressure. Checked radiators and pipework for any leaks...all seems ok (not checked under floorboards yet).

    With CH on the pressure seems to be stable, rising a little as expected. I checked the pressure relief pipe outside and it was slightly damp, so will get PRV replaced at some point.

    But I’ve noticed when the boiler is turned off, it’s losing pressure. The condensate pipe outside is dripping. Even if the boiler is off for a few days I can see a wet patch below the condensate pipe, the pressure relief pipe is dry. I’m assuming this is the reason why the boiler is losing pressure.

    Any one got any thoughts as to why the condensate pipe is dripping?

    Any help/advice is appreciated.

  2. terrymac

    terrymac Well-Known Member

    Heat exchanger has a pin hole leak. Call in a professional gas engineer.
  3. fazse

    fazse New Member

    Thanks for the reply Terrymac,

    I have been checking prices for a heat exchanger and a new one costs £500. Is it possible to repair a heat exchanger?

    Will I do any harm to the boiler if I continue to use the boiler in this condition and top up the pressure regularly?
  4. Mike83

    Mike83 Well-Known Member

    Take a pic of the condensate pipe. (Confirm it’s the correct pipe)

    I’m not sure how you can see it’s dripping, it should be sealed pipework. Unless it’s been disconnected.
  5. Mike83

    Mike83 Well-Known Member

    How old is the boiler. It may be under warranty.
  6. fazse

    fazse New Member

    The boiler is around 10 years old.

    The plastic condensate pipe on the outside wall is covered by another longer plastic tube which runs down the wall finishing above the ground. The pipe is dripping into stone chippings, there is a wet patch below the tube, also the tube is wet/damp at the bottom.

    I will upload a daylight photo tomorrow.
  7. fazse

    fazse New Member

    This is a picture of the pipes outside. The overflow pipe looks like it’s been leaking in the past as the colour of the wall is a bit bronze but it was dry today.

    The plastic pipe is the condensate pipe which is leaking. The boiler has been off for 3 days and you can see a wet patch below the pipe, the pipe is wet/damp to touch at the bottom.

    Attached Files:

  8. Mike83

    Mike83 Well-Known Member

    What is the copper pipe in the second picture?
    Is it gas.
  9. Mike83

    Mike83 Well-Known Member

    Is it possible to remove the black plastic pipe. If so then tie something around the white pipe to contain any water.
    This eliminates any water running down between the 2 pipes messing with the test.

    Has the pressure still been dropping with the boiler off
  10. Mike83

    Mike83 Well-Known Member

    You could also top up pressure to 2 bar then isolate the boiler at the flow and return valves.
    This will confirm it’s the heat exchanger.

    It looks almost certain it’s the heat exchanger.
  11. fazse

    fazse New Member

    Yes the pressure is dropping when the boiler is off.

    The copper pipe is a gas pipe to the boiler.

    Last week I topped the pressure up and isolated the boiler, the pressure still dropped.
  12. Allsorts

    Allsorts Well-Known Member

    Sounds almost certain to be the main exchanger.

    Can it be repaired? Not in any way I know. I guess there's no harm in trying a leak sealer in your system water to try and gain yourself a bit of time to save up for a new boiler - it's hardly worth having the exchanger replaced unless you can somehow get it done cheaply, eg from a trusted 2nd-hand part if such a think exists.

    It's a shame it's 10 years old; if it had been significantly less than this then I reckon you'd have a decent chance of getting WB to pay for it.
  13. Mike83

    Mike83 Well-Known Member

    Remove all leaves and debris from around that gas pipe.
    The waste from the condensate pipe is corrosive to copper.
    The condensate pipe has been terminated incorrectly from looking at that picture.
  14. fazse

    fazse New Member

    It must have been like that for 10 years, I’m surprised it’s not been changed. Should it terminate into the drains
  15. Mike83

    Mike83 Well-Known Member

    Waste drains or a soak away.
    I would be checking the gas pipe for corrosion
  16. fazse

    fazse New Member

    Would the stone chippings area be classed as a soak away, the plastic pipe could be angled away from the gas pipe.

    I’ve drawn a red line form the condensate pipe to the waste drain, would that be a correct setup?

    Attached Files:

  17. Mike83

    Mike83 Well-Known Member

    Yes. Better than current set up.
    Soak away has to be about 600mm from building.
  18. Mike83

    Mike83 Well-Known Member

    What’s the black pipe on the ground.
    Looks like it should be on the boiler flue:
  19. fazse

    fazse New Member

    I think it’s a redundant waste pipe. Where would that go on the flue? The flue sticks out of the wall as normal.
  20. Mike83

    Mike83 Well-Known Member

    Looks like a plume management kit for boiler

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