(206) 949-5683, Top Rated Plumber, Seattle
Results 1 to 12 of 12

Thread: vacuum relief valve?

  1. #1
    DIY Junior Member KKfromNJ's Avatar
    Join Date
    Sep 2008
    Location
    NJ
    Posts
    5

    Default vacuum relief valve?

    I live in New Jersey and am replacing a 10 year old gas water heater; the instructions (Kenmore) mention a expansion tank or a vacuum relief valve. We have neither now, do I need one, is it required?

    Thanks
    KK

  2. #2
    Plumber patrick88's Avatar
    Join Date
    Sep 2007
    Location
    Webster Ma.
    Posts
    836

    Default

    Quote Originally Posted by KKfromNJ View Post
    I live in New Jersey and am replacing a 10 year old gas water heater; the instructions (Kenmore) mention a expansion tank or a vacuum relief valve. We have neither now, do I need one, is it required?

    Thanks
    KK
    If the installation instructions tell you one is needed then you need it. If you don't have one they may not honor any implied warranty.
    I'm just starting to work with an old friend of mine to bring solar electric and hot water systems, wind turbines, Flex Fuel Boilers, batteries, hydroponic gardening, books, pellet grills and more. Also the parts for DIY installation.

  3. #3
    Retired Defense Industry Engineer jadnashua's Avatar
    Join Date
    Sep 2004
    Location
    New England
    Posts
    21,376

    Default

    You may or may not need an expansion tank. Water expands when it is heated. It can exert signficant pressure - enough to damage a water heater if it has nowhere to go. Many homes have what is referred to as a closed water system - it comes in, but is prevented from back-flowing back to the supply. This can be caused by a check-valve or a PRV. If you have either of those, then you should have an expansion tank. If you don't have a closed system, the expanded water goes back out to the main.

    A vacuum relief valve would prevent damage if the wrong set of circumstances existed to the tank.

    One other thing that is required in some places is a tempering valve to restrict the outlet water temperature should the WH thermostat fail, or you wanted to extend its capactity by storing hotter water than is typically safe. By having hotter water stored in the tank, you can mix more cold in, depleting the tank slower. You'll lose more energy because the bigger the differential between the tank and the room is larger, but not to heat it since you are using less.
    Jim DeBruycker
    Important note - I'm not a pro
    Retired Defense Industry Engineer; Schluter 2.5-day Workshop Completed 2013, 2014

  4. #4
    DIY Junior Member KKfromNJ's Avatar
    Join Date
    Sep 2008
    Location
    NJ
    Posts
    5

    Default

    Thanks for the help; I appreciate everyone’s time. I just took a look, the tank has a pressure relief valve (PRV ?) and there isn’t any other valve between the tank and the house supply. The instructions say install a expansion tank if you have a closed system and the vacuum relief valve says "according to local codes".

    Thanks
    KK

  5. #5
    Retired Defense Industry Engineer jadnashua's Avatar
    Join Date
    Sep 2004
    Location
    New England
    Posts
    21,376

    Default

    Not quite...the safety valve on the WH is a T&P (temperature and pressure) relief valve. A PRV is a pressure-reduction valve which is usually located close to the water inlet of the house - near the shutoff and water meter.

    A vacuum breaker can be useful anywhere, and is required in some areas.
    Jim DeBruycker
    Important note - I'm not a pro
    Retired Defense Industry Engineer; Schluter 2.5-day Workshop Completed 2013, 2014

  6. #6
    DIY Junior Member KKfromNJ's Avatar
    Join Date
    Sep 2008
    Location
    NJ
    Posts
    5

    Default

    We only have the meter and then the shutoff. I’m going to install a vacuum relief valve.

    Thanks

  7. #7
    Master Plumber nhmaster's Avatar
    Join Date
    Jul 2008
    Location
    S. Maine
    Posts
    2,039

    Default

    Since this is a gas water heater, did you call the gas utility first? They don't look kindly on folks messing with gas piping without permits and inspections. You should also give a call to the local plumbing or mechanical inspector to verify the venting is proper.

  8. #8
    Retired Defense Industry Engineer jadnashua's Avatar
    Join Date
    Sep 2004
    Location
    New England
    Posts
    21,376

    Default

    Some meters have a built-in check valve...you need to check with the utility or your inspector. If it does, that makes it a closed system, necessitating the expansion tank.
    Jim DeBruycker
    Important note - I'm not a pro
    Retired Defense Industry Engineer; Schluter 2.5-day Workshop Completed 2013, 2014

  9. #9
    DIY Junior Member KKfromNJ's Avatar
    Join Date
    Sep 2008
    Location
    NJ
    Posts
    5

    Default

    Quote Originally Posted by nhmaster View Post
    Since this is a gas water heater, did you call the gas utility first? They don't look kindly on folks messing with gas piping without permits and inspections. You should also give a call to the local plumbing or mechanical inspector to verify the venting is proper.
    Funny thing about the gas company, glad you brought it up. I’m replacing this for my parents who had a “service contract” with PSE&G. My Dad called them first, of course water heater replacement was NOT covered in the contract, worthless. The PSE&G guy told me I’d be better off having someone else replace it because PSE&G really charged a lot, at least $900. I said I was pretty handy, built my parents rear addition, did the electrical, hot water baseboard (not the boiler) etc. He suggested it was piece of cake, easy. Said if I had any doubts when I was done, call them they would check it out. I found that strange. Last time I saw our plumbing inspector, he was so drunk he could barely make it down the basement stairs.

    I’ll try and find out about the water meter, but it is about 20-30 years old, this will be our 4th water heater and we’ve never had a expansion tank on the water line. I’ll have to see if I can find out.

    Thanks Again
    KK

  10. #10
    Master Plumber nhmaster's Avatar
    Join Date
    Jul 2008
    Location
    S. Maine
    Posts
    2,039

    Default

    Well then, best of luck to you.

    Just remember though GAS GOES BOOM

  11. #11
    In the Trades Gary Swart's Avatar
    Join Date
    Sep 2004
    Location
    Yakima WA
    Posts
    7,245

    Default

    Kk from NJ, check your private messages.
    Last edited by Gary Swart; 09-05-2008 at 01:58 PM. Reason: spelling error

  12. #12
    Moderator & Master Plumber hj's Avatar
    Join Date
    Aug 2004
    Location
    Cave Creek, Arizona
    Posts
    25,605

    Default valve

    Some places use PRV to indicate a pressure relief valven and use the term interchangealby with termperature and pressure relief valve. A vacuum relief valve is only necessary if the water heater is in one of the upper levels of the house or in the attic.

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •