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Dual hot water tanks

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  • Dual hot water tanks

    First of all I'll say "hello there!" I recently started my own business in Calgary and this seems like a good place to get some advice.

    Problem: Two 40 gallon hot water tanks connected in series (gas) 6 years old. Even though the homeowner turned them up one 'click' away from Max, the water doesn't seem to be as hot as it should be. I turned on some taps and the hot water also ran out faster than it should have for two tanks.

    While the taps were running the primary tank (the one the water enters first) lit, followed by the second tank some time later.

    I'm thinking that it could be the dip tube in the primary tank...or...the temperature sensor on the gas valve on the primary. Any ideas?

    Thanks in advance

  • #2
    Re: Dual hot water tanks

    If you have a little time on your hands you can perform a little test without taking anything apart. With both heaters up to temp, have the homeowner turn on the fixture that they are experiencing the lack of hot water with and you hang out with the water heaters. By occasionally touching the outgoing piping on both heaters you may be able to determine if one or both have a bad dip tube. It's important that you are aware of the flow from the fixture being used as this may actually be part of the problem. Note on your watch how long it takes for the hot water to run out, I have seen some shower valves that were the problem. In addition you should determine how old these heaters are as it may be more cost effective to install new ones.


    • #3
      Re: Dual hot water tanks

      when you say in series, does the hot out of one serve as the "cold" into the other? this issue came up in another thread in the forum and i believe the solution was to repipe the HW heaters in parallel, so the hot out of both combined to serve the users.
      there's a solution to every just have to be willing to find it.


      • #4
        Re: Dual hot water tanks

        The tanks are 6 years old, and the problem started a few months ago. I know that this isn't young for a water tank but I'd like to try and fix the problem first. Did I mention its my wifes boss? (what the hell have I done!?)

        I'm still kind of leaning towards the temperature sensor. When a tank is set to one click below its highest setting it is normally scalding, but it was just comfortable to touch. I will definately give the dip tube test a go.

        1) If the dip tubes are ok, which gas valve is most likely the problem? I'm thinking the primary tank?

        2) I've heard of the plastic part of the dip tube getting stuck in the threads when the metal part is it worth messing with?