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Not Enough Hot Water ????????

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  • Not Enough Hot Water ????????

    I have 100 unit 4 story apt. building, L shaped, two A. O. SMITH
    cyclone 399,000 btu, 130 gal. water heaters feeding 3 appox.
    400-600 gal. storage tanks, that feed the building all 1 bd/rm'
    1- bathrm. no dishwasher's 2 laundry rooms with total 9 washer's H/E commc's. the problem is the building mgt. wants 130% water supply at mech. room, but only getting somewhere
    between 105- 110% up/strs, min. temp. per. health dept. 110%
    at all kitchen faucets, this is a 1 yr. old building,
    ???? did they leeve out recerc. pumps ???
    if not and you were plumbing this building how would you run recerc's from what end points ???
    one return off the end of each floor ??
    one off the forth floor ??

    P. S. the mech. room is on the first floor at base of the L,
    SINCE JAN. 1989

  • #2
    Re: Not Enough Hot Water ????????

    1. What is the temperate range set at on the water heaters?

    2. Do you notice a return line to the cold water line going into the water heater, should be easy to spot because it should have a check valve on it.

    3. I would think one return off each floor would be the best idea.

    Next time just call me boss.
    Proud To Be Union!!


    • #3
      Re: Not Enough Hot Water ????????

      You should be able to see if there are recirc pumps?????

      If you need to run recirc lines you will need one off the highest point of each riser.

      How about raising the temp of the water heaters to 140* and using a tempering valve like a holby to temper it to 130*

      ***your posts are a tough read, maybe use a spell check***
      Last edited by Masterplumb; 04-16-2008, 09:34 PM.


      • #4
        Re: Not Enough Hot Water ????????

        This is probably not what you want to hear, but here it is anyway:

        Did you do the original installation? If so, who did the design work; the plumbing contractor, the architect, or an engineer?

        If the building is only one year old, something is wrong with either the design or the installation. Be careful. Trying to find solutions can turn into an expensive, fruitless experience. Has the A.O. Smith rep been out? Who spec'd the heaters? ( FWIW- It sounds like it is NOT a water supply problem). If an engineer designed the system were his plans followed? If not, why not?

        If you did not do this installation be careful that you do not "buy" responsibility by trying a bunch of solutions that do not work. Where are the original contractors? Why haven't they solved this problem?

        Also to be considered: Are the owner's expectations consistent with reality? Is there really a problem or just unreal expectations of owners? Did the owners leave off a recirc line because of cost? Our code requires a recirc line in buildings of this size, does yours? If it is required and not there, how did it pass inspection?

        You need more information, don't start throwing money at this until you are certain what the real problem is.

        Again be careful, your responsibilities are much different if you did the original work than if you are being called in after the fact. Be certain to have a clear definiton of the problem before trying to solve it.

        Were hot water lines insulated all the way to the farthest point? In a large building you could be leaving the boiler room at the desired temp but have a lot of heat loss until it gets to the last unit. Are there thermometers on the heaters so you get accurate information?

        If you did not do the original install, remember the Kenny Rogers song...."you got to know when to walk away..."

        By the way did I mention "be careful".

        Side note: if you change the font on your post it would be easier to read. It gets changed in the little control panel at the top of the posting box
        Last edited by APHCO; 04-19-2008, 08:32 AM.