Too long for Recirculation Pump?

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by mlawrence, Oct 5, 2007.

  1. mlawrence

    mlawrence New Member

    Joined:
    Oct 4, 2007
    I'm building a house that's "L" shaped with 3 bedrooms at the end of one leg of the "L" and a kitchen/half bath/Laundry in the other leg. My plan was to put the water heater right near the kitchen/half bath/laundry area so that they would get hot water pretty quickly and run a grundfos recirculation pump with a dedicated return line from the farthest bathroom. Since the house is an "L" shape the distance from the water heater to the farthest bathroom is about 100'. I'm using 3/4" pex for main line connected to manifolds with 1/2" pex running to each fixture. Is 100' ok for that main line or will I have a problem with the water cooling down by the time it gets there?
     
  2. geniescience

    geniescience Homeowner

    Joined:
    Nov 27, 2005
    Occupation:
    ditto
    Location:
    humid summers hot, humid winters cold
    insulation. What have you thought of?

    david
     
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  4. mlawrence

    mlawrence New Member

    Joined:
    Oct 4, 2007
    I haven't really thought about insulation. But I guess I'd wrap the pex in foam pipe insulation.
     
  5. geniescience

    geniescience Homeowner

    Joined:
    Nov 27, 2005
    Occupation:
    ditto
    Location:
    humid summers hot, humid winters cold
    summertime, and the cooling is expensive. Hot water is flowing, and the bills are high.


    you want to deliver hot water hot, and cold water cold. You want hot water to stay hot, and cold water to stay cold. Only insulation does that.

    Without insulation, the luke-hot water you would get anywhere would have been adding to your energy bill twice, once for having been heated, and once more again for having imparted its heat energy into your walls when you are paying money for the energy you need to run AC or whatever you use to stay cool.

    I am assuming you live somewhere south of the Arctic circle, and you need to prevent the house from getting too hot in summer. As much as you "need" anything else in terms of comfort and plumbing.


    david
     
  6. mlawrence

    mlawrence New Member

    Joined:
    Oct 4, 2007
    I can wrap the pipe in some insulation without a problem. I guess I should wrap the return line of the recirculating pump as well????
    So that's about 200' of pipe insulation.
     
  7. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Joined:
    Sep 2, 2004
    Occupation:
    Retired Systems engineer for defense industry.
    Location:
    New England
    The return is going back into your WH, so, the colder it is when it gets back, the more you have to heat...insulate everything. Consider putting the recirculation on a timer, or, if you can wait for it, maybe a motion sensor in the room or a simple time-delayed relay circuit where it runs for a specified time when manually activated.
     
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