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Balancing a system with lock shield on outlet

Discussion in 'Plumbing and Central Heating' started by CRBerk11, 17 Oct 2021.

  1. CRBerk11

    CRBerk11

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    I need some help, having real difficulty balancing my radiators. Got modern slim rads upstairs, columns downstairs. Downstairs the rads are all on the right way. Upstairs, TRVs and lock shields are mostly on the wrong way. I understand they are bidirectional, but when trying to balance the system, the lock shield side (inlet in many cases) gets v hot and the TRV doesn’t. The rads do get hot upstairs… but downstairs they’re not. I can’t get the inlet and outlets to match temperature-wise if I keep lockshield valve a quarter open. So does that mean, as they are effectively wired backwards, that I need to open the lockshields more, to get the valves to within 12c? As this seems to go against the normal way to balance the system. I’m obviously a bit lost here. I just want hot radiators downstairs! Thanks all.
     
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  3. oldbuffer

    oldbuffer

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    It doesn't matter which side the lock shields are on. The aim of balancing is to get the flow the right speed to allow the radiator to lose sufficient heat to give temperature drop of the required amount. The normal drop is 11 degrees for a non-condensing system, and 20 degrees for a condensing system provided the radiators are sized for condensing.
     
  4. CRBerk11

    CRBerk11

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    Ok, thanks. So if the lockshield is red hot, the radiator is hot, but the trv is only lukewarm, what should I do? The radiator is hot after all… but does that mean the system won’t be properly balanced?
     
  5. Bouy

    Bouy

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    And if you turn your lockshields off upstairs and TRVs on highest setting downstairs what happens
     
  6. CRBerk11

    CRBerk11

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    Well all the lockshields upstairs are now a quarter turn open and TRVs fully open. All rads upstairs are hot. Everything downstairs is stone cold. I have a modern valiant boiler and 8 rads across first floor and loft; 3 towel rails (which I’ve not got on too hot) and 5 column rads downstairs.

    Thank you for your help - I’m totally stumped! And getting cold.
     
  7. Mottie

    Mottie

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    Have you done this ^^^^
     
  8. CRBerk11

    CRBerk11

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    Not yet… I will do that and let you know.
     
  9. Bouy

    Bouy

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    Boiler rating?
     
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  11. Mottie

    Mottie

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    Pump speed?
     
  12. CRBerk11

    CRBerk11

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    Not sure! “Designed and manufactured by Vaillant, the ecoTEC Plus 637 is a condensing system gas boiler that would suit the heating and hot water demand of larger homes.”
     
  13. CRBerk11

    CRBerk11

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    So now the lockshields are closed everywhere else, the downstairs rads are warming up. The inlets are very hot, rads are slowing getting warm, outlets less so but they are column radiators so I guess it takes a while?
     
  14. CRBerk11

    CRBerk11

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    How do I find out the pump speed?
     
  15. Mottie

    Mottie

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    Try opening the lock shields up. When the downstairs rads are all flowing hot, start cracking open the upstairs ones and see what happens. Sounds like the system isn’t balanced to me.
    I think you have to do it via the programme but if you’re not sure, I wouldn’t touch it if I were you - perhaps get an engineer round.
     
  16. CRBerk11

    CRBerk11

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    I can try that, but the downstairs radiators aren’t super hot anyway… so I am guessing there is a big problem here. The bigger column rads aren’t getting hot to touch, just warm.
     
  17. Mottie

    Mottie

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    Are they plumbed in the right way round? Some column rads have to be.
     
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