Grundfos pumps

Discussion in 'Plumbing and Central Heating' started by Matt887, 19 Feb 2021.

  1. Matt887

    Matt887

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    What's the difference between these two pumps. Guessing ones more of a 'smart' pump?
     

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  3. MeldrewsMate

    MeldrewsMate

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    About £300 difference, I think.
     
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  4. Matt887

    Matt887

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    Correct yes. Is it worth the extra money for the magna one?
     
  5. Quilts76

    Quilts76

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    This really depends on the system it is fitted too.
     
  6. Matt887

    Matt887

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    Could you elaborate please?
     
  7. Quilts76

    Quilts76

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    What is the system it is running?
    Rads how many?
    Zones?
    Age?
    There are many factors
     
  8. Matt887

    Matt887

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    Sealed system central heating
     
  9. Matt887

    Matt887

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    Heat only boiler 35 rads. No zones to the system.
     
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  11. Matt887

    Matt887

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    Quiet an old system all copper 28/22mm with 15mm to the rads.
     
  12. Matt887

    Matt887

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    I take it the grundfos magna is a smart pump? That will adjust its pressure of its pump to the system demand?
     
  13. D_Hailsham

    D_Hailsham

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    Both pumps have been discontinued by Grundfos, so what you have found are end-of-line stock.

    With 35 radiators, you have a very large system. Has anyone calculated the system index (max head and flow rate), so you know what size pump to buy?
     
  14. Matt887

    Matt887

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    Sadly not. The pump is the highest point of the system really. So not sure what this means with regards to max head. As its at the heightest point. Any help. Would be greatly appreciated. The pump on the old heat only boiler that was in was only a 15/50 60. Grundfos.
     
  15. TimboTwo

    TimboTwo

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    UPS15-50 is 130mm long.
    Those two are 180mm long.
    Be a tight squeeze!!
     
  16. Gasguru

    Gasguru

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    Google index circuit, the position and height of the system is irrelevant...head refers to frictional loss in the system when circulating the water at the maximum required rate. So a 6m Grundfos can create a 6m pressure drop across the system when the flowrate drops to zero...you'd never run the pump like that obviously.
    What's the boiler make and model?
     
  17. D_Hailsham

    D_Hailsham

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    There's an inconsistency between the statements above as a "sealed system" normally means a system boiler boiler with integrated pump; while a "heat only boiler" is usually open vented with a external pump.

    We need to know exactly which boiler is being fitted - make and exact model.

    If the old system worked OK with a Grundfos 15-50/60 (which model?), you shouldn't need an 8m pump.
     
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