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hot water line

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  • hot water line

    Why is it when you cut open both cold and hot waterlines while the water is off, the hot water will still have a small flow of water long after the cold stops?

  • #2
    Re: hot water line

    Thermal expansion or Murphy's law.....
    Poor Planning On Your Part Does Not Constitute An Emergency On My Part!!
    You can fire me...but you can't tell me what to do!



    • #3
      Re: hot water line

      You want to stop the hot water from flowing? Open the drain on the water heater and drain off a gallon or two.
      Ron Hasil Lic #058-160417
      Ron's Facebook
      A-Archer Sewer & Plumbing specializing in:
      Tankless Water Heaters | Drain and Sewer Cleaning
      Sump and Ejector Pumps | Backflow RPZ Testing


      • #4
        Re: hot water line

        What sort of hot water system is it mains pressure (tanked) which when a hot water tap is turned on after turning of the supply tap the hot water will continue until the pressure in the tank is releaved or a gravity feed where the hot water tank has a supply tank (a header tank) in the roof which has to be drained before you can work on the hot water line or tap.



        • #5
          Re: hot water line

          the water heater has a dip tube on the cold inlet from a top fed heater.

          depending on the style of heater/ top fed or side fed will dictate the relationship of the water level to the inlet and outlets.

          a top fed heater should not siphon on the hot side as the nipple is not submerged like the cold with a dip tube. although the dip tube does have an anti siphon hole towards the top of it.

          a side feed heater will siphon until the level drops below the inlet and outlet.

          then of course if there's an expansion tank, there will be some back pressure before it drains down.

          next time open up an upper level faucet to allow for the pipes to drain down faster.

          phoebe it is