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Which Central heating pump should I buy?

Discussion in 'Plumbing and Central Heating' started by cooa99, 3 Sep 2021.

  1. cooa99

    cooa99

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    Hi all,

    My sister just had a single rear extension done. It's an end of terrace. Ground floor rear extension. This has resulted in adding to the current central heating system 3 new radiators i.e. a Towel rad in the new toilet, a 40cm rad and a 45cm tall vertical column rad in the extension

    Builder in their infinite wisdom did not test the heating till all building work has been completed and now say the lack of heating to the furthest 2 radiators in the extension (i.e 40cm rad and the vertical rad) is boiler issue which I think is wrong.

    All existing Rads gets piping hot so no obvious signs of sludge. I have tried balancing by shutting off a couple of existing rads to see if the heat will get to the last 2 rads but they just gets Luke warm and then back to cold.

    Boiler is a Baxi conventional and relatively new. Pump is Grundfos UPS 15-50 (130) ... but does make a fair bit of noise, possibly cuts on and off so I am thinking this might be the issue.
    oldpump.jpg

    So radiators in the house are:-
    1st floor : 3 rads and 1 towel rad rad
    ground floor : 2 * 180cm rads, 1 * 40cm rad, 1 towel rad, 1 * 45cm (wide) tall vertical column rad


    My question is do I buy the Grundfos UPS3 15-50/65 (£115) or a more powerful pump? If I need one with more power which one?



    Thanks
     
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  3. blup

    blup

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    You might need a bigger supply pipe at the radiator end to improve flow, rather than a more powerful pump to increase pressure.

    Blup
     
  4. muggles

    muggles

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    Do the new radiators work if you turn all the other ones off? Could just be an airlock, or they could be piped up incorrectly. Vertical rads are particularly sensitive and many need the flow & return to be connected at the correct end for them to work properly. They also need to be fitted the right way up!
     
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  5. Gasguru

    Gasguru

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    A significant no. of no name vertical rads (especially bought from online bathroom suppliers) do not work...
     
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  6. ianmcd

    ianmcd

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    unlikely to be the circulator (it is not a pump) some vertical rads have a baffle installed and the pipe orientation is critical, if the builder has got the flow and return mixed up and the rad has a baffle it will never work
     
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  7. cooa99

    cooa99

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    Something else I noticed was that the existing pump is upside down (I reoriented the picture in my previous post for clear reading). Is that normal?. She bought the house 4 yrs ago and never had issues with the heating...

    They used plastic pipes (buried in concrete ) to the last radiator. Is that normal?

    I turned off 4 rads (which included the 2 * 180cm) with no joy, bled again, and the last 2 rads they fitted barely gets warm. I am convinced they did not fit well. He send a plumber (or maybe a CH engineer) round yesterday night who said the issue is the pump. I don't fully agree but I am no expert!

    The Vertical rad has a label on in to show inlet and outlet so I will hope the fitter noticed this!

    The simplest option for now ( to save my sister's sanity) is to pay for a new pump as requested by the builder. I take the viewpoint that the pumps needs replacing anyway due to its current noise levels so not a particularly pointless change.

    If that does not fix the issue, she can get an independent in to fix. If it turns out to be bad pipework by the builder then the cost of can be deducted from the final balance to be paid to him which he is now asking for.

    So coming back to the main question, which pump should she buy?.
     
    Last edited: 3 Sep 2021
  8. muggles

    muggles

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    The DAB Evosta is a good circulator with a bit more power than your existing Grundfos. I'd be very very surprised if changing your circulator fixes the problem though. You need to turn off ALL the existing rads including the towel rails to do the test, and maybe one of the new ones too. Let it run for 5-10 minutes then see what gets hot.

    The circulator doesn't know which way up it is, having the wiring upside down makes no difference.

    And definitely don't pay your builder until everything is working.
     
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  9. cooa99

    cooa99

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    Yep, I have told her NOT to had over the balance yet till its clear where the fault is.
    Hopefully they will fit a new one over the weekend.
     
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  11. Terrywookfit

    Terrywookfit

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    What size pipework is feeding these new rads.
     
  12. SpecialK

    SpecialK

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    Take the pump body off and see if the impellers are blocked? You should be able to isolate the pump and undo those 4 Allen keys.
    What speed is the pump on?
     
  13. cooa99

    cooa99

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    The pipes are standard 15mm. I was going to put the new pump she bought myself but she said she would rather have the builder's man do it so just incase they blame it on me if it does not work. Hopefully they will turn up tomorrow
     
  14. cooa99

    cooa99

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    Some update on what has happened. The CH engineer that the builder sent Installed a new circulator Pump and came to conclusion that the new rads were not installed correctly. The builder has told him to rectify the issue .... which I am assuming would mean abandon plastic pipe work to the tall rad (since buried in concrete under wooden floor )and fit a new one.

    Now the question is which route should the pipework take?. Attached is picture of the extension. Blue line is the existing pipework.
    extrad.jpg
    Am I correct in my thinking that the new pipework to the Tall rad should be as I have shown (red) in the picture?. Is it possible to dig a channel through the concrete by the doorway or that's a no no?
     
  15. oldbutnotdead

    oldbutnotdead

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    Depends what's wrong with the installation. If they've been plumbed wrong way round that can be fixed (unless only 1 has been reversed, in which case more tricky).
    If the pipe size is inadequate then yes new pipe time. You can channel into concrete, it's messy and making good is a pest but doable (long as it's ground support not block & beam).
    I also suspect that your sister hasn't paid good money to have a load of pipework clipped to the skirting board- rectification should include having the same standard of finish as current (ie pipes hidden).
    Depending on what the walls are made of, which way the ceiling joists go etc. it may be easier to hack chunks off the walls and ceiling, run the pipes up over and down and make good.
     
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  16. muggles

    muggles

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    Agree with @oldbutnotdead it needs to be re-done to the same standard as the original (except ensuring it works this time of course!). Don't accept short-cut solutions which won't look as nice.
     
  17. cooa99

    cooa99

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    mmm.... what a mess. I am assuming the new guy will want to do his work fully and not have to worry about shoddy work by previous plumber.

    From pics my sis sent me during build, I think whole area was filled with concrete. Could channeling not result in a crack all the way to the dpc ?

    Regarding the wall (of the extended portion) I think they covered the brick with plasterboard.
     
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