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Dead ends and Legionnaires?

ChrisJ
ChrisJ Member Posts: 11,970
Hi all,

We're currently doing a lot of repiping and have a few walls open.

While doing this I want to run a return for my domestic hot water from the second floor bathroom but it would just be a 10' long plugged 3/4" run of pex for a long time. Maybe forever.

It's just in case I ever get the time to do recirculating hot water and since it's in a wall now's the time to do it.

Is this asking for something really bad?
Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment

Comments

  • Jamie Hall
    Jamie Hall Member Posts: 17,042
    I wouldn't think so, @ChrisJ . Just when you do hook it up, flush it well!
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
    ChrisJ
  • Larry Weingarten
    Larry Weingarten Member Posts: 2,283
    Hi, I'd see if there was a way to put a shut off valve at the beginning of the run to minimize the dead leg.

    Yours, Larry
    ChrisJZman
  • ChrisJ
    ChrisJ Member Posts: 11,970
    > @Larry Weingarten said:
    > Hi, I'd see if there was a way to put a shut off valve at the beginning of the run to minimize the dead leg.
    >
    > Yours, Larry

    Hi Larry,

    I thought about that but it's going to be in a drywalled ceiling so no dice. :(
    Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment
  • Larry Weingarten
    Larry Weingarten Member Posts: 2,283


    Hi, Can't use one of those beautiful hatches? o:)

    Yours, Larry
    Solid_Fuel_Man
  • ChrisJ
    ChrisJ Member Posts: 11,970
    > @Larry Weingarten said:
    > (Image)
    >
    >
    > Hi, Can't use one of those beautiful hatches? o:)
    >
    > Yours, Larry

    Are you married @Larry Weingarten ? :p

    Actually, we were considering doing a dropped ceiling for this reason as well as I want access to the tub drain etc.

    I don't like how they look but at the same time I don't like loosing all access to everything below the second floor bathroom.
    Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment
    Zmanethicalpaul
  • ratio
    ratio Member Posts: 2,919
    Not all lay-in ceiling tiles are ugly. Some look pretty good; I'm especially fond of the stamped tin ones. They are not, unfortunately, cheap. Another (expensive but) durable & unobtrusive tile is the drywall squares used in commercial kitchens.
  • Solid_Fuel_Man
    Solid_Fuel_Man Member Posts: 2,304
    Just build yourself some type of hidden access. I built my own house and let me say there are a few "hidden access points" for cooler things than a valve!
    Serving Northern Maine HVAC & Controls. I burn wood, it smells good!
    ethicalpaul
  • ChrisJ
    ChrisJ Member Posts: 11,970
    > @Solid_Fuel_Man said:
    > Just build yourself some type of hidden access. I built my own house and let me say there are a few "hidden access points" for cooler things than a valve!

    Gladly.

    Any suggestions?
    Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment
  • Solid_Fuel_Man
    Solid_Fuel_Man Member Posts: 2,304
    Will it be buried in a wall or floor?

    I assume wall, will it be close to your shower faucet? Can you put it under a false bottom shelf or cabinet?
    Serving Northern Maine HVAC & Controls. I burn wood, it smells good!
  • ChrisJ
    ChrisJ Member Posts: 11,970
    > @Solid_Fuel_Man said:
    > Will it be buried in a wall or floor?
    >
    > I assume wall, will it be close to your shower faucet? Can you put it under a false bottom shelf or cabinet?

    Drywalled ceiling under the second floor bathroom. Second floor bathroom has tile floor.

    We gutted the first floor bathroom which is where the work is being done.

    The plugged end would be in the crawl space under the first floor bathroom.
    Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment
  • hot_rod
    hot_rod Member Posts: 15,017
    can you make a loop so it could be circulated?

    This German company builds a Venturi fitting to induce flow in loops that are not used daily

    https://www.kemper-olpe.de/fileadmin/contents/kemper/pdf/KHS_EN_02_13.pdf
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • ChrisJ
    ChrisJ Member Posts: 11,970
    hot_rod said:

    can you make a loop so it could be circulated?



    This German company builds a Venturi fitting to induce flow in loops that are not used daily



    https://www.kemper-olpe.de/fileadmin/contents/kemper/pdf/KHS_EN_02_13.pdf

    After mulling it over and looking at options, I may have come up with an idea which would make the dead end only a foot long or so.
    Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment
  • JUGHNE
    JUGHNE Member Posts: 8,934
    Chris, do you have access to the bottom of your lav sink?
    I connected my recir line there and have a stop valve on it.
    Gravity recir to bottom of water heater tank only one floor down. Works great, instant hot water water in the shower with no pump involved.
    Search the wall for "Gravity recirculation". There is a Dec 2018 posting with many details.
    Solid_Fuel_Man
  • HomerJSmith
    HomerJSmith Member Posts: 1,362
    Gee. It's hard to say. 90 deg to 120 deg is an ideal breeding ground for the bacteria. Dead legs are of course in that range for the hot water line. I always try and avoid dead legs. As far as the circulation of hot water in a DHW line goes, new piping will be scrubbed to some extent with circulation. However, heated chlorinated water will break down the the piping barrier in all pipes allowing over time, places where bacteria could lodge. Water hardness and mineralization of the interior could, I would think, provide niches for bacteria to congregate, too.
  • ChrisJ
    ChrisJ Member Posts: 11,970
    > @HomerJSmith said:
    > Gee. It's hard to say. 90 deg to 120 deg is an ideal breeding ground for the bacteria. Dead legs are of course in that range for the hot water line. I always try and avoid dead legs. As far as the circulation of hot water in a DHW line goes, new piping will be scrubbed to some extent with circulation. However, heated chlorinated water will break down the the piping barrier in all pipes allowing over time, places where bacteria could lodge. Water hardness and mineralization of the interior could, I would think, provide niches for bacteria to congregate, too.

    New piping will be scrubbed But chlorinated water will break down the piping barrier? Huh?
    Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment
  • HomerJSmith
    HomerJSmith Member Posts: 1,362
    edited October 2019
    Chrisj, to clarify your huh?, what I meant was that new pipe is much smoother inside and therefore the bacteria has less to cling to and can be more easily washed away. Hot chlorinated water breaks down the barrier layer on the inside of the tube, allowing the bacteria something to cling to. The piping that most resists this breakdown is CPVC as I understand it.
    ChrisJ
  • ChrisJ
    ChrisJ Member Posts: 11,970
    > @HomerJSmith said:
    > Chrisj, to clarify your huh?, what I meant was that new pipe is much smoother inside and therefore the bacteria has less to cling to and can be more easily washed away. Hot chlorinated water breaks down the barrier layer on the inside of the tube, allowing the bacteria something to cling to. The piping that most resists this breakdown is CPVC as I understand it.

    Ah I see.
    That makes sense.
    Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment