Turndish leaking water and boiler dropping pressure

Discussion in 'Plumbing and Central Heating' started by platforminc, 30 Jan 2021.

  1. platforminc

    platforminc

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    Hi All.

    I hope everyone is well and keeping safe, I have come onto the forum for some help and explanation before I take my next steps.

    I have an unvented cylinder setup and I really do not understand it, I have always been used to a combi setup and this is much more complicated. The installation was done by my builders heating engineer 5 months ago, and I am still struggling to understand how things work.

    In this case, he changed the PRV 3 weeks ago, and about thesame time the shower valve in the bathroom upstairs was not getting hot, he adjusted it and then it was too hot for the kids, and now its kind of lukewarm, I mention this as I do not know if its related.

    This morning, I noticed a lot of water coming from the turndish and falling onto the zone valve underneath which is in close proximity. I had to use a nylon to cover the zone valve.

    From a helpful youtube video that I watched (), it implied that its one of 5 potential issues.


    PRV - Which was replaced a few weeks ago when the turndish was leaking water.
    Expansion vessel needing a charge
    Back pressure
    System overheating
    Issue with the inlet control set

    20210130_114034.jpg
     
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  3. Madrab

    Madrab

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    No1 - don't turn any of the red turn knobs, they are pressure release valves and once turned they may not close properly again.

    The main issue you have here is that although it is for the central heating system, it's all part of the unvented safety release/discharge system and therefore you really need someone that is qualified to look at it. Each valve outlet needs to be checked to see which one is passing.
     
  4. ianmcd

    ianmcd

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    the blue handled valve in your pic is open it should be closed, that white expansion vessel is for the cylinder and nothing to do with your primary system pressure dropping
     
  5. platforminc

    platforminc

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    Thanks for the observation. You will notice that the filling loop is closed. There are 2 valves, one is the blue one there is another one.
     
  6. platforminc

    platforminc

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    Thanks for the comment. I will not touch anything again.
    What happened is that a heating engineer friend of mine reckons that the issue is from the boiler pressure valve. He did say that since the boiler is less than a year old, I should get in touch with worcester. I was thinking, is he saying this because he doesnt want to come out and have a look or is this the truth. This is the reason I asked for help on the forum.
     
  7. platforminc

    platforminc

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    One other observation, I am trying to understand why we use 10kw of gas a day. We have got underfloor heating and an unvented cylinder for hot water and radiators upstairs. On the worcester boiler, I see the radiator icon on a lot, I know from experience with combi's that once the flame sign is on, it means that gas it being burnt, if the radiator sign is illuminated on the boiler, does this mean that gas is being burnt ?

    The setup is that we have the UFH manifold and a pump which pumps hot water around the UFH circuit.
     
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  9. ianmcd

    ianmcd

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    Yes I do know how a filling loop works, both need to be closed
     
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  10. Madrab

    Madrab

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    If the loop was passing then the pressure on that gauge would rise, once it gets near 3 bar the valve starts to lift, equalising the pressure. You need to turn the other valve off, as mentioned by @ianmcd, and remove the braided hose and see if the pressure on that gauge continues to rise. You don't want that gauge to read much more than 1.5bar cold. If it doesn't rise then the boiler probably isn't the issue so nothing Worcester would do.

    There are several reason's why there's water is the tundish, you have 3 valves any which could be opening and a separate reason why each might be.

    Your "heating engineer friend", who should also be unvented qualified, needs to diagnose the system and see which one is creating the water in the tundish and confirm if the boiler is at issue. If not then get someone that will.
     
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  11. platforminc

    platforminc

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    I have turned off the blue valve now.
    The braided hose, please kindly explain further (which end to take off, the blue end or the black end). which guage you are talking about, is it the one close to the white stop cap ? IF I take it off, will this cause water to be everywhere ? and how long should I take it off for ?
     
  12. ianmcd

    ianmcd

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    The braided hose should be disconnected permanently, and only connected when needed , it is a water By-law nothing to do with gas
     
  13. Madrab

    Madrab

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    +1 .... the braided hose is classed as a temporary connection between the cold water and the CH system. Once each valve is turned off there should be no water in the pipe (well just what's in the pipe). Removing it will prove whether the filling loop is passing and over pressurising the CH, causing the Pressure Reducing Valve to open. There is only one gauge in your pic.

    Even then I'd still be getting someone that is prepared to test everything and identify what is causing the water in the tundish.

    If your boiler is running, then dependent on how long the boiler is running for determines how much gas it will use. The radiator sign means that the system is calling for heat, only when the flame light is on is it using gas.

    Very roughly, if your HO boiler is using 10Kw of gas per day then that isn't very much at all, that's roughly about £0.40p
     
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