Return line 32mm or 40mm

Discussion in 'Pumps and Waterflow' started by sandersc, 14 Jul 2015.

  1. sandersc

    sandersc

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    I received my return pump yesterday and saw that both the inlet and the outlet of the pump is 40mm. My question now is which size return pipe would be the best, 32mm or 40mm?

    Initially I thought 32mm , but now I am leaning towards 40mm.

    Any suggestions?

    Sanders
     
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  3. zippy

    zippy

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    a lot of this is pump dependent, viscosity and the like of water moving thru a pipe, if the pump is over rated the 40 should work fine, if it isn't you may struggle to reach the head height required to drop the water into the DT.
     
  4. sandersc

    sandersc Thread Starter

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    The pump is the dct 12000 and max height is about 1.5m
     
  5. zippy

    zippy

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    should be fine with the 40mm
     
  6. sandersc

    sandersc Thread Starter

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    But do you think it will be better than the 32mm?
     
  7. zippy

    zippy

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    when you say "better" what are you actually looking for, or what would you require the pump to do other than circulate the water from sump to DT? IF you need more info we'll need more info in terms of the size of the DT and sump.

    Do you have a DSB in the mix, possibly a refugium?

    What are your concerns surrounding the flow?
     
  8. mariusmeyer

    mariusmeyer

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    With 40mm you will have less velocity / thrust (for a lack of a better word) out of the pipe compared to 32mm.
     
  9. mariusmeyer

    mariusmeyer

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    Do you have a design for the tank with plumbing that we can see?
     
  10. sandersc

    sandersc Thread Starter

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    The only reason why I am rethinking the whole issue, is because when I saw the 40mm outlet on the pump I thought perhaps it should be best going with 40mm plumbing. What will be the effect long term be on the pump , if any , using 32mm or 40 mm?

    I plumbed for 32mm, but I can always use my third 40mm downpipe ( emergency one ) for my return and use the 32m pipe as my 3rd ( emergency ) downpipe.
     
    Last edited: 14 Jul 2015
  11. zippy

    zippy

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    rather stick to the 32mm pump line, iirc the Pump has a variable control on it, it shouldn't bother the pump in a noticeable way, even the height will play a roll in the longevity of the pump, however you will prolly end up a grandfather before the pump gives way on the new tech, and the impeller will give out way before then. On full tilt that pump would wear out the glass on the other end of the tank before the pump comes to any harm because of the jet of water that would come out of the 32mm pipe, if I were you, I wouldn't be overly concerned.
     
  12. JackSplat

    JackSplat

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    These pumps are centrifugal, i.e. at maximum flow it works the hardest, at no flow it, the least. The reason they ship with such a large connections is to maximise flow. If you are happy with a small penalty in pressure loss then it is ok. This calculator will show you the difference.

    Calculator: Pressure Loss through Piping for Water | TLV

    Smaller pipes does have higher flow velocity and may be noisy though.
     
  13. dallasg

    dallasg Moderator MASA Contributor

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    I have the 10000L version of the pump and used a Marley 40mm to 50mm screw adapter and used 50mm pipe, I then tap off and reduce depending on what I need, I return to one tank using 32mm, the other tank 20mm and reactors etc use 25mm
    I have unions and valves to adjust, I just used what I had lying around but 32mm is most common
     
  14. sandersc

    sandersc Thread Starter

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    @JackSplat my thinking exactly. Larger diametre, less resistance, less energy, this is why I would prefer to have 40mm.
     
    Last edited by a moderator: 26 Nov 2015
  15. sandersc

    sandersc Thread Starter

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    Last edited by a moderator: 26 Nov 2015
  16. JackSplat

    JackSplat

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    Last edited by a moderator: 26 Nov 2015
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