pump for hot water heater

Discussion in 'Plumbing Forum, Professional & DIY Advice, Tips & ' started by shimmies99, May 20, 2011.

  1. shimmies99

    shimmies99 New Member

    Messages:
    16
    Location:
    S Florida
    **sorry, should have posted in different forum** I don't know how to remove this posting though.

    It takes a long time for hot water to make it to my kitchen downstairs or my shower upstairs. My neighbor showed me a pump placed inline with water supply that she'd had installed. She had to plug it in with each use, but it reduced time and water flow waiting for hot water. I'd never heard of seen such a thing. How do they work? Are they safe? What happens if you leave it on all the time? Thanks
    Last edited: May 20, 2011
  2. jimbo

    jimbo Plumber

    Messages:
    8,997
    Location:
    San Diego
    It is called retrofit recirculation. The pump goes at the water heater, and a device called a crossover valve goes under the sink at the farthest away location. The pump can be on a timer or switch. There is also a temperature switch so that when water at the far end is about 80º ( and ready to get hotter!) the pump turns off.

    The modest heat loss and electric cost of the pump is made up for by the convenience and not having to waste water down the drain waiting for it to get hot.

    There is a side effect: You will briefly have warm (~80º) water from the cold tap each time you turn it on.

    Google 'grundfos comfort system' to learn about these. There are other brands and variations, but the idea is the same.
  3. cacher_chick

    cacher_chick Test, Don't Guess!

    Messages:
    3,246
    Location:
    Land of Cheese
    If you leave it running, the water heater will have to run more often, causing an increase in energy use.
    Some of this loss can be reduced by insulating the hot water supply piping.
  4. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,607
    Location:
    Cave Creek, Arizona
    If the neighbor had the "right" type of system, she would NOT have had to plug it in every time, so I am not sure if she had some "cobbled together" device which would NOT be the same as the systems we are referring to.
  5. LLigetfa

    LLigetfa DIYer, not in the trades

    Messages:
    3,967
    Location:
    NW Ontario, Canada
    Ja, as was mentioned in your other thread, there are several brands available. I just saw the Watts unit at Manerds.
    Last edited by a moderator: May 22, 2011
  6. Gary Swart

    Gary Swart In the Trades

    Messages:
    7,347
    Location:
    Yakima WA
    The best recirculation system uses a dedicated return line from the farthest point from the water heater. In a retro fit, that is not always practical to do. Insulate the hot water pipes is good advice. You can get models with a timer that turns the pump on/off at chosen times. My model does not have a timer and runs 24/7 I'm sure there is some cost involved, but it is not much. Sometimes I want hot water at 2 or 3 in the morning. It's been running for something like 8 years without a hitch.
  7. shimmies99

    shimmies99 New Member

    Messages:
    16
    Location:
    S Florida
    OK, you've given me some places to start my research. My neighbor said what she had installed was a "pump", cost about 40 dollars and was simple enough that her son could install it (not sure what the implication was there.) I don't know if any of those things were completely accurate or just what she was trying to recall. I do know it had a plug and she would plug it in then start the dishwasher. I can ask her more, but this forum is probably a much better resource, now that I've moved beyond toilets. thankies!
  8. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,607
    Location:
    Cave Creek, Arizona
    quote; My neighbor said what she had installed was a "pump", cost about 40 dollars and was simple enough that her son could install it (not sure what the implication was there.)

    The PROPER installation IS simple enough that her son could do it, but NONE of the systems cost $40.00 and for that price there is almost NOTHING that could do the job correctly. She probably just has a "pressure pump" and when she turns it on it forces the water out of the faucet faster so the hot water arrives sooner, but does NOT save on the water bill.
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