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-   -   Heat trap loop in a multi-story building? (https://www.askmehelpdesk.com/showthread.php?t=724875)

  • Dec 29, 2012, 02:47 AM
    Energysave
    Heat trap loop in a multi-story building?
    Hello, I've been reading a lot on DHW heat traps (nipples and loops) and I have a question on loops.

    Do the loops only work in houses where the hot water faucets are at the same or lower level than the hot water outlet of the heater?

    I live in an apartment building on the 4th floor and our oil (diesel really) heater is in the building's basement along with the hot water tank. So there's a very significant column of water in the piping that takes hot water all the way from the basement level to the apartment (probably 40-45 ft). The situation is the same on the cold inlet to the heater as well, as our cold water storage is in tanks placed on the roof of the building, so an even higher column of water sits on top of the cold inlet.

    I checked our heater and therre are no heat trap loops or nipples. I'm suspecting significant heat loss from heat being thermosyphoned up through the hot water supply line to the apartment.

    Will a heat trapping loop work in this set up? It seems to me that the really tall column of water on the output side of the loop will prevent it from Functioning correctly.

    I really am not sure. I read somewhere that the trapping part of the loop is actually an air pocket the forms in the top portion of the loop. If that is the case, then where would that air come from especially in my case where both the faucets and the cold water storage are 40+ ft up?

    Can someone help clarify all of this for me and maybe also help me save some energy :D?

    p.s. I live outside the US, in Jordan to be exact :)
  • Dec 29, 2012, 03:58 PM
    massplumber2008
    Hi Energysave

    Are you concerned with heat loss here or time to get hot water to the apartment? Let me know as each issue has different ideas/answers, OK?

    Mark
  • Dec 29, 2012, 11:12 PM
    Energysave
    Hi Mark, I'm significantly more concerned with heat loss.
    Thanks.
  • Dec 30, 2012, 06:07 AM
    massplumber2008
    Heat trap nipples help with heat loss, for sure.

    Heat trap loops are a simple piped u-shaped trap setup that create a micro circulatory loop within the trap that keeps heat from being transferred up past the loop (air is NOT involved).

    With that being said, if you don't have either then your best bet would be to insulate the first 10-15 feet of hot water piping coming out of the water heater. The first 10-15 feet of hot water piping is where the greatest heat loss is found at water heating devices. After the 10-15 feet, heat loss is said to be "negligible" and the cost of the insulation and labor are considered unnecessary according to the water heater manufacturers I have talked to over the years. You would also insulate the first 5 feet of the cold water inlet.

    Another spot of great heat loss is through the temperature and pressure relief valve... this can also be insulated, but do NOT interfere with the ability of the lever device to open/trip.

    That should cover heat LOSS, but I still wonder if you are having trouble more so with time to get the hot water to your apartment than heat loss. In this case, an insulated gravity recirculating line would be a great addition to the system and would make hot water available almost instantly at your unit. Let me know if you want to discuss more on that, OK?

    Mark

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