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  1. #1
    Join Date
    Oct 2012
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    Shelby NC
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    129

    Default Water heater supply lines both hot.

    I was in a double wide today and checking a 30 gal electric water heater. I noticed that both the supply line going in and the hot line coming out were both hot at about the same temp. Never noticed this before. Any idea if and what the malfunction might be. Could it be the pipe inside that sends the cold water to the bottom is broke off and down inside?

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  2. #2
    Join Date
    Mar 2007
    Location
    Columbus GA
    Posts
    3,746

    Default Re: Water heater supply lines both hot.

    Possible thermal expansion.
    Water heats up in the WH and expands
    If all valves are off, there is no place for the water to expand
    Heated water backflows through cold water line to city water line or well.

    ' correct a wise man and you gain a friend... correct a fool and he'll bloody your nose'.

  3. #3
    Join Date
    Dec 2008
    Location
    Maryland
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    2,778

    Default Re: Water heater supply lines both hot.

    It is possible that the hot water line has a circulator (passive or active) that causes the hot water to come back into the tank so that each faucet has hot water without waiting.


  4. #4
    Join Date
    Mar 2007
    Location
    Philadelphia PA
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    3,177

    Default Re: Water heater supply lines both hot.

    Quote Originally Posted by Garry Sorrells View Post
    It is possible that the hot water line has a circulator (passive or active) that causes the hot water to come back into the tank so that each faucet has hot water without waiting.
    Not that I know much about them, but, in a double wide?

    "There is no exception to the rule that every rule has an exception." -James Thurber, writer and cartoonist (1894-1961)
    www.ArnoldHomeInspections.com

  5. #5
    Join Date
    Mar 2007
    Location
    Plano, Texas
    Posts
    4,170

    Default Re: Water heater supply lines both hot.

    I know this is obvious for most of us, but for the lurkers that might read this. Did you run the hot water taps immediately before checking the temperature of the hot and cold lines? Obviously if there is not movement of water through the lines, then both lines will be warm due to conduction from the tank.

    Jim Luttrall
    www.MrInspector.net
    Plano, Texas

  6. #6
    Join Date
    Oct 2012
    Location
    Shelby NC
    Posts
    129

    Default Re: Water heater supply lines both hot.

    Yep, ran the water, found several faucets that were reversed plumbed.


  7. #7
    Join Date
    Mar 2007
    Location
    Plano, Texas
    Posts
    4,170

    Default Re: Water heater supply lines both hot.

    But did you check the supply and discharge pipe temperatures at the heater immediately after running the hot?

    I can't see any reason for the water flowing INTO the heater to be hotter than the normal cold water temperature.

    I did have a house that had hot and cold pipes running the length of the house which were wrapped together in insulation which in effect created a heat exchanger. The hot and cold became the same temperature at the far end of the house but NOT at the heater.

    The only explanation I can see is if there was a recirculating function of some kind feeding hot water back into the cold water supply upstream of the place where you checked the temperatures.

    Jim Luttrall
    www.MrInspector.net
    Plano, Texas

  8. #8
    Join Date
    Dec 2008
    Location
    Maryland
    Posts
    2,778

    Default Re: Water heater supply lines both hot.

    Quote Originally Posted by John Arnold View Post
    Not that I know much about them, but, in a double wide?
    I agree it would be strange/unusual. But people do strange things.


  9. #9
    Join Date
    Mar 2007
    Location
    Spring Hill (Nashville), TN
    Posts
    5,847

    Default Re: Water heater supply lines both hot.

    I think I would go with the thermal expansion theory...... Water heats up in the tank and it heads back down the supply pipe as it expands. Now if the home has a PRV or a backflow device that shoots this theory down.

    Scott Patterson, ACI
    Spring Hill, TN
    www.traceinspections.com

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