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hot water!

I work in a rural hospital, the building is 5 years old and we have had continued hot water fluctuations. a Bradley S59-3200 mixing valve at my tank is pretty reliable for keeping temp but as it gets out into the building we have some areas that hardly ever get to temp at the faucet??? I've replaced a recirc pump that seemed to help for a short time, but i still have places where i turn the hot water on and its cool for 10 seconds then gets slightly warmer and then just goes cold? It's been a 5 year mystery and drives me nuts some days. Any Help?

Comments

  • neilc
    neilc Member Posts: 2,086
    do you have as builts?
    are they accurate?
    a closed valve there somewhere and you're getting backflow thru recirc?
    unbalanced recirc lines?
    janitor / bedpan / dishroom sink with sprayer head, and the faucet is on both sides, and cold water is crossing over?

    known to beat dead horses
    Zman
  • neilc
    neilc Member Posts: 2,086
    and the 3 pot sink in the kitchen,
    2 faucet handles, then a third to stop flow on the common spout,
    they always turn off the 3rd stop, and we cross over.
    It's always the kitchen !
    known to beat dead horses
    delta T
  • Mark Eatherton
    Mark Eatherton Member Posts: 5,839
    What he said. You have a cross connection between hot and cold water some place that needs found and fixed with check valves. A pain to find, but as
    Noted usually a post mix shut off valve at the root of the problem. Mop sinks and prerinse sprays are notorious.

    ME
    It's not so much a case of "You got what you paid for", as it is a matter of "You DIDN'T get what you DIDN'T pay for, and you're NOT going to get what you thought you were in the way of comfort". Borrowed from Heatboy.
    delta T
  • Daryn
    Daryn Member Posts: 3
    Good info thank you guys! Our as builts are not that great and i have found a valve on the patient floor that was closed and fixed that problem in that area. Surgery and preop are the problem areas now which is coincidentally right next to the kitchen. thanks for the new leads i will keep ya posted.
  • neilc
    neilc Member Posts: 2,086
    yeah,
    I didn't think about the scrub stations them selves,
    are these foot operated?
    same scenario, mixed water being controlled by that third valve,
    so it could be right in the room itself, one basin to the other,
    or room to room,
    good hunting,
    let us know what you find
    known to beat dead horses
  • JUGHNE
    JUGHNE Member Posts: 10,291
    From my experience it is always the mop sinks. The chemical man hangs his dispenser on the wall, hooks his hose to the faucet and turn the hot on. All the signage in the world will not keep someone from turning on the cold also which creates a cross connection.
    Perhaps some mop sink faucets have check valves built into the unit to prevent this. Sometimes the cold is shut off or the handle is removed.

    And it was pointed out to me that keeping the vac breaker on the faucet under continuous pressure is illegal and will remove that level of protection. And eventually keep the vac bkr closed as the check is stuck to the top because of the continuous pressure.

    My wife has worked at the same hospital for nearly 40 years, when the toilets are flushing with hot water she tells maint and all the new guys wonder how she knows. ;)
  • Daryn
    Daryn Member Posts: 3
    So we have three eye wash station in that wing, i turned them all off and hot water came back. i got rebuild kits coming for them and will hope that is the problem for now.
  • neilc
    neilc Member Posts: 2,086
    @JUGHNE
    and when the janitor finally reads, is forced to read, the manual we see that we are only supposed to use cold water in the chem dispensers.
    who reads manuals ?
    @Daryn
    your eyewashes have builtin checks ?
    what model?
    known to beat dead horses
  • hot_rod
    hot_rod Member Posts: 18,208
    Often times fixtures like that have point of use mixing valves ASSE 10790. Andn if so that valve should have check valves in the tailpieces.

    Just one central mixing valve at the tank is not enough for 100% temperature protection.

    Is the valve at the tank a Hi-Low type? a big mix valve with a smaller one attached. To get accurate temperature at low flows you need a 1/2 or 3/4 valve, and the larger one for all fixtures flowing.

    Could be the recirc loop has balancing valves that were never adjusted also?
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • JUGHNE
    JUGHNE Member Posts: 10,291
    The hospital I speak of has 2 eye wash/showers, they are suppose to have mix valves, 1 is above the ceiling, the other in a flush wall box with door.