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Worcester Greenstar 30CDI Boiler - constantly on during eco

Discussion in 'Plumbing and Central Heating' started by Sam Cutler, 6 May 2021.

  1. Sam Cutler

    Sam Cutler

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    Hi there,

    I've just moved into a new house and have a Worcester Greenstar 30CDI boiler.

    The boiler is constantly humming away and giving off heat so must be heating something. I presumed this was the pre-heat function since when we moved in, the eco button wasn't lit up green and the temp was showing 50C or so. It's pretty noisy and so I turned eco on - however, the boiler doesn't seem to do anything differently. It's still humming, hot water is still almost instant and the temp display still shows 50C or so. I've tried resetting it or switching it on/off but nothing seems to work. If I switch it off and on again or reset with eco on, it'll not make any noise and the temp gauge will gradually go down. However, the moment I use a hot tap it'll go back to constantly making the humming sound and giving off heat (preheating again?) again until I reset it again.

    I have no idea what to do to get it to stop constantly heating water and making noise. Any ideas?

    Thanks in advance for the help.
     
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  3. CBW

    CBW

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    Do you have a combi boiler, or a tank? Do you have any motorised valves installed?
     
  4. Sam Cutler

    Sam Cutler

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    Hi Chris, thanks for the response. It's a combi I believe. Greenstar 30CDI combi. I have no idea if it has a motorised valve - is it easy to see if it has one?
     
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  5. CBW

    CBW

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    Yes easy enough to find, either just above the boiler or perhaps in a cupboard. Looking for similar to this: upload_2021-5-7_21-11-46.jpeg
     
  6. ianmcd

    ianmcd

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    your boiler can be installed with an internal diverter valve (optional) but if you dont have an external HW cylinder then you dont have one so the ECO button doesnt actually do anything, can you control the heating upstairs and downstairs seperately ? if you can you will have two zone valves and one has a sticking micro switch
     
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  7. Sam Cutler

    Sam Cutler

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    ]

    Hi both, I can't see a motorised valve nor can I see an external HW cylinder or a cylinder in the attic at all. I don't have any way of controlling upstairs and downstairs separately, I can just control all the heating via a digital thermostat downstairs. In any case, if the eco button doesn't work, then why is the boiler always seemingly running with a temperature of 55C on the dial?
     
  8. ianmcd

    ianmcd

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    your boiler can be installed a few ways, sounds like you have a combi set up, can you post a pic of the controls facia on the boiler and a pic of any external controls so we can see what the boiler thinks is happening, if installed as a combi, the ECO button doesnt do anything
     
  9. CBW

    CBW

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    I thought this was the preheat on/off, on these models?
     
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  11. Sam Cutler

    Sam Cutler

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    3822C375-752C-4502-B5D1-3ED2447F05B2.jpeg
    Photos attached if that helps. Showing the front panel and downstairs thermostat. Number on the thermostat is the current temp. The gas light turns on when I put on hot water or the heating and I get this whirring sound. Otherwise just get this constant background sound that almost sounds a bit like a car engine (when a car is started up but not driving) rumbling in that it’s inconsistent (it sort of bumbles along) if that makes sense.
     

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  12. ianmcd

    ianmcd

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    you need to tope your system pressure up a bit, but that is not the cause of your problem, do you have a receiver unit with the Drayton, thermostat ? post a pic of that with the thermostat turned down
     
  13. Johnmdc

    Johnmdc

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    That programmer (DT10rf) is for the preheat on the hot water. You have it set to constant so it will always be on.
    But having said that the preheat should only run fit a few minutes every hour or so, then stop.
    It is also the receiver for the wireless controller for the heating.
     
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  14. Sam Cutler

    Sam Cutler

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    Thanks for the quick responses by the way, really appreciated.

    I can't seem to find the receiver. Would it be found near the boiler? The boiler cupboard doesn't seem to have a receiver in it. Are the receivers usually isolated as there are at least 3 miscellaneous isolator on/off switches and I'm not quite sure where they go and what they lead to, so it's conceivable one could lead to the receiver unit if they are installed with isolators.
     
  15. ianmcd

    ianmcd

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    when the ECO button is illuminated it cancels the DHW pre heat function
     
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  16. Johnmdc

    Johnmdc

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    Even with the built in programmer?
    To the OP press the left hand button on the programmer that says select once this should stop it.
    And as I said the receiver is built into that programmer on the front of the boiler.
     
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  17. ianmcd

    ianmcd

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    yes sorry I was wrong with the DT10 the receiver is part of the on board programmer
     
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