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Discuss Suitable Pump Replacement in the Central Heating Forum area at UKPlumbersForums.co.uk.

  1. Berksguy

    Berksguy New Member

    My existing pump is on the way out. It's a Grundfos ALPHA 15-60 130 and about 16 years old. If I use the Grundfos replacement guide it comes out with an ALPHA2 15-60 130 as a suitable replacement. My system is quite large (22 radiators) and I have found, even after balancing, that the radiator furthest away from the airing cupboard struggles to get very warm. Is it worthwhile upgrading the pump to a light commercial one or stick with the suggested ALPHA2?

    Thanks for looking,

    Steve
     
  2. ShaunCorbs

    ShaunCorbs S. Mod Trusted Plumber GSR Top Contributor!!

    is your system sealed or open vented?
     
  3. Berksguy

    Berksguy New Member

    It's sealed.
     
  4. ShaunCorbs

    ShaunCorbs S. Mod Trusted Plumber GSR Top Contributor!!

    Would stick an 25-80 if you can adjust the pipework
     
  5. king of pipes

    king of pipes Trusted Plumber GSR

    Dab Evosta 40-70 would be a good affordable replacment these pump can be fitted to most domestic systems with switchable head settings. Kop
     
  6. Berksguy

    Berksguy New Member

    Thanks for all the replies.

    I can get a Grundfos Magna 25-100 for no cost. It's a bit of a beast. Do you think that will be overkill or should I make use of it as it's free?
     
  7. doitmyself

    doitmyself Well-Known Member

    I would check your balancing. The lockshields should normally be less than one turn open. Start will all LS valves half a turn open. Then make very small adjustments (1/12th turn or less). Only adjust one rad at a time, and wait five minutes for the change to work. You may even find that the pump can be turned down.
     
  8. Berksguy

    Berksguy New Member

    I can get a Grundfos Magna 25-100 for no cost. It's a bit of a beast. Do you think that will be overkill or should I make use of it as it's free?
     
  9. ShaunCorbs

    ShaunCorbs S. Mod Trusted Plumber GSR Top Contributor!!

    no cost??
     
  10. king of pipes

    king of pipes Trusted Plumber GSR

    Bit overkill really you could end up with excessive noise through your heating pipework radiators and valves it needs sizing to your actual design of your system . kop
     
  11. Berksguy

    Berksguy New Member

    Yes no cost. I have been offered this pump from a friend who purchased a job lot of stock from a bankrupt business.
     
  12. Berksguy

    Berksguy New Member

    I wouldn’t want to have excessive noise in the pipes etc.. I had thought that the AUTOADAPT feature would prevent this from happening.
     
    Last edited: Apr 2, 2018
  13. king of pipes

    king of pipes Trusted Plumber GSR

    Well by all means give it a try your choice bud you have nothing to loose it may need a small alteration on the pipwork . cheers kop
     
  14. Berksguy

    Berksguy New Member

    After seeing how large the Magna 25-100 is (it's about the size of a small family car), I've decided to go with a UPS2 25-80 and have managed to source one for a very good price. This is similar in size to my existing pump and will be easier to fit in, as space is a bit tight in my airing cupboard.

    I am looking for a recommendation for a heating engineer to carry out the adjustments to fit the pump. I will also want to add a Magnaclean and an auto bypass valve at the same time. So if any can recommend someone who carries out work in the Reading area then please let me know?

    Steve
     
  15. doitmyself

    doitmyself Well-Known Member

    An auto-bypass can only be used if the pump is set to a fixed speed. It is incompatible with proportional pressure as the bypass will open more as the pressure increases.

    However, the flow/head curves for the UPS2 25/80 are 'flat' up to a flow of 2 to 3 m³/hr, which is equivalent to 23 to 35kW (at 10C differential) or 46 to 70 kW (at 20C diff), depending on pump speed. This means that any auto-bypass will be either open or closed all the time (depending on setting). So an auto-bypass, on its own, is effectively unusable with this pump in most domestic situations.

    The way round this is to run the pump in proportional mode and have a fixed flow valve (e.g Taconova Setter) in series with the auto-bypass. The bypass will open at the required setting but the flow will be restricted by the Setter valve.
     
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