Hot water recirculation

Discussion in 'Plumbing Forum, Professional & DIY Advice, Tips & ' started by Gary Swart, Nov 26, 2004.

  1. Gary Swart

    Gary Swart In the Trades

    Messages:
    7,329
    Location:
    Yakima WA
    I recently encountered a Laing Auto Circ device on sale at a box store. This is a pump that circulates the hot water in your home so that you will have hot water instantly when you turn the fixture on. I liked the idea, but this is a retro-fit model that uses the existing cold water lines to return the hot water, and that didn't appeal too much to me. I contacted the Laing company about using a separate return line, and they replied that they had models that used a return line and that would be preferred if it was possible to install the return line. My plumbing is entirely exposed in the basement, so this did not represent any problem for me. I found a Laing SM-303-BTW on eBay that I obtained for less that $100, and while I was waiting to receive it, I did most of the plumbing, got the automatic air vent, cut off valves, etc. that are required, so when I got the unit, it took less than an hour to complete the installation. Friends, this is an amazing device! Where it used to require 15 seconds or so to purge the cold water for the hot water line in my shower, it now take less than 2 seconds. Virtually instant hot water. It find it curious that there has never been a mention of this on this forum, at least that I have seen, and I have even posted questions regarding ways to accomplish this.
  2. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,488
    Location:
    Cave Creek, Arizona
    water

    I am not sure about this site, but it is a constant subject on others, and the dedicated return line, when possible, the Laing Auto-Circ, (and others like it), and the Grudfos Comfort Zone which is similar except the pump is at the water heater and the conrol valve is under the sinks are always mentioned as possibilities. Just remember that your utility bill will increase because of the constant demand on the hot water heater, and its life will be decreased for the same reason.
  3. Gary Swart

    Gary Swart In the Trades

    Messages:
    7,329
    Location:
    Yakima WA
    Re circulation pump

    Guess I've just miss seeing those comments. I'm sure there will be an increase in the gas bill, but for me this will be the price of the luxury of having hot water without a delay. Thanks for the comment.
  4. Spaceman Spiff

    Spaceman Spiff Architect

    Messages:
    277
    Location:
    Salt Lake City, Utah
    I'm not too worried about the extra fuel and loading on the heater, it's almost insignificant compared to the thousands of gallons you use each month... I do, however, use rigid fiberglass insulation to insulate all of the HW and return lines to keep down heat loss and place as much of the tubes as I can in interior heated spaces. I suspect this way the owner spends more on the electricity to run the pump than to heat the water.
  5. Gary Swart

    Gary Swart In the Trades

    Messages:
    7,329
    Location:
    Yakima WA
    Insulation

    I've been considering the foam pipe insulation for some time. I don't think the cost to operate the pump will be enough to notice at all, but there will be heat loss from the pipes since there are now two hot lines and they are both full of hot water all of the time. The insulation will likely be more cost effective that ever now. Not a big job with all of my pipes exposed in the basement.
  6. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,896
    Location:
    New England
    While you are at it, do the cold pipes, too. Then in the summer, they won't sweat.
  7. jk60

    jk60 Engineer

    Messages:
    189
    Location:
    San Francisco
    I know it's been awhile since this thread was posted, but can you tell me what are the other sites you are referring to where the Laing Auto-Circ and the Grundfos Comfort Zone are discussed.

    Thank you,

    Jerry
  8. BacchusII

    BacchusII New Member

    Messages:
    7
    Location:
    W NY State
    I installed a Hot to cold water line bypass/check valve many yrs ago that had the same effect w/o the cost / energy req'd to run a recirc pump. The unit is added at the farthest or most freauently used point (master bath sink in my case). It uses the cold water line to return but could also be piped w/ a separate line if desired. I don't recall the manufacturer but some searching might turn something up.
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