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  1. #1
    Join Date
    Mar 2007
    Location
    Daniel Island, SC.
    Posts
    230

    Default Water heater expansion device in new construction

    Hello!

    Looking at the picture, is this installed correctly. Or like the PRV extension, it has to be installed going down hill since it is gravity fed. Thanks, Jim

    2015-07-23 01.33.12.jpg

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  2. #2
    Join Date
    Mar 2012
    Location
    Lansdale, PA
    Posts
    876

    Default Re: Water heater expansion device in new construction

    It is not gravity fed. It operates by pressure, so orientation does not matter.

    The reason why a TPRV discharge pipe goes downhill is so water cannot sit in the pipe.

    This relief valve should not be isolated from the water heater by a shut off valve.


  3. #3
    Join Date
    Mar 2007
    Location
    Daniel Island, SC.
    Posts
    230

    Default Re: Water heater expansion device in new construction

    Thanks,

    Would you please explain in more detail, "This relief valve should not be isolated from the water heater by a shut off valve."

    Jim



  4. #4
    Join Date
    Oct 2014
    Location
    CA
    Posts
    2

    Default Re: Water heater expansion device in new construction

    Quote Originally Posted by JIM MURPHY View Post
    Thanks,

    Would you please explain in more detail, "This relief valve should not be isolated from the water heater by a shut off valve."

    Jim
    The relief valve has to directly connected and available to open under high pressure or temperature at all times. If the visible shutoff valve is closed the TPV is isolated from the tank and provides no protection.

    Bad consequences become possible.


  5. #5
    Join Date
    Mar 2007
    Location
    Ormond Beach, Florida
    Posts
    26,248

    Default Re: Water heater expansion device in new construction

    Quote Originally Posted by Todd Harrison View Post
    The relief valve has to directly connected and available to open under high pressure or temperature at all times. If the visible shutoff valve is closed the TPV is isolated from the tank and provides no protection.

    Bad consequences become possible.
    That valve in the photo is not a temperature and pressure (T&P) relief valve, it is a pressure only relief valve. The reason for that valve is thermal expansion when the water heater is on and heating the water, so, as Mark said, the pressure relief valve should be on the tank side of the shut-off valve (the shut-off valve should not be between the pressure relief valve and the tank).

    Having that shut-off valve there will not ... 'SHOULD NOT' is the better wording ... cause any harm to the water heater or anything around it as the T&P relief valve is still installed in the tank - hopefully a proper T&P is properly installed in the tank.

    The thermal expansion pressure relief valve is there to keep water from being pushed back into the utility's supply to the house. Nothing else.

    Jerry Peck, Construction / Litigation Consultant
    Construction Litigation Consultants, LLC ( www.ConstructionLitigationConsultants.com )
    www.AskCodeMan.com

  6. #6
    Join Date
    Oct 2014
    Location
    CA
    Posts
    2

    Default Re: Water heater expansion device in new construction

    Quote Originally Posted by Jerry Peck View Post
    That valve in the photo is not a temperature and pressure (T&P) relief valve, it is a pressure only relief valve. The reason for that valve is thermal expansion when the water heater is on and heating the water, so, as Mark said, the pressure relief valve should be on the tank side of the shut-off valve (the shut-off valve should not be between the pressure relief valve and the tank).

    Having that shut-off valve there will not ... 'SHOULD NOT' is the better wording ... cause any harm to the water heater or anything around it as the T&P relief valve is still installed in the tank - hopefully a proper T&P is properly installed in the tank.

    The thermal expansion pressure relief valve is there to keep water from being pushed back into the utility's supply to the house. Nothing else.
    Which shows that Jerry knows a great deal more than I on this subject, listen to his words, not mine!


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