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Vacuum relief valve

steve_29
steve_29 Member Posts: 185
in THE MAIN WALL
I hope someone can answer this for me. There is a on going debate whether a vacuum relief valve is required for a hot water tank. Some say yes some say no. Help...

thanks

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Comments

  • Brad White_200
    Brad White_200 Member Posts: 148
    Yes

    It prevents a tank implosion and is required by ASME and ANSI, but I do not have the chapter and verse handy right now.

    For thirty bucks you want to save? Oy. Just do it.
  • steve_29
    steve_29 Member Posts: 185


    Thanks Brad, I concur with you, but I'm being told that the new tanks don't need it.

  • Jim Franklin
    Jim Franklin Member Posts: 170


    I just found something interesting...

    504.1 Antisiphon devices. An approved means, such as a cold water “dip” tube with a hole at the top or a vacuum relief valve installed in the cold water supply line above the top of the heater or tank, shall be provided to prevent siphoning of any storage water heater or tank.

    504.2 Vacuum relief valve. Bottom fed water heaters and bottom fed tanks connected to water heaters shall have a vacuum relief valve installed. The vacuum relief valve shall comply with ANSI Z21.22.

    Ya learn something new every day.
  • jackchips_2
    jackchips_2 Member Posts: 1,337
    When

    we first stayed at our place in Florida there was no vacuum valve on the water heater and I was quite concerned. I called the installer and was told because each building was on a backflow preventer they were not required.

    I had not thought about them again until now. I have not heard of any problems with them not being installed but would have prefered one.

    Different state, different rules. I'll just have to invest in a small propane gas set-up and install my own.
  • STEVE PAUL_3
    STEVE PAUL_3 Member Posts: 126
    vacuum reief valves

    The NSPC requires vacuum relief valves on the cold water side of water heaters that have outlets at a lower elevation than the tank. This is to:


    1- Prevent syphoning water from the tank.

    2- Preventing the hot water from flashing to steam if the water in the tank is subjected to a below atmospheric pressure (vacuum).

    3- Preventing a n internal vacuum from cuasing a tank collapse.
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