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Thread: PRV??

  1. #1
    mathew stouffer's Avatar
    mathew stouffer Guest

    Default PRV??

    I have never seen one of these before. Is this a PRV and is it adjustible.

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  2. #2
    Join Date
    Mar 2007
    Location
    Plano, Texas
    Posts
    4,170

    Default Re: PRV??

    No, does not appear to be a pressure reducing valve. Looks like this:
    Watts Brass & Tubular 3/4" Back Flo Preventer LF7U2-2 3/4

    A simple check valve.

    Jim Luttrall
    www.MrInspector.net
    Plano, Texas

  3. #3
    Ray Norton's Avatar
    Ray Norton Guest

    Default Re: PRV??

    That's a double check valve used to protect the municipal water supply. It is probably required by that particular Public/ Water Works Department/ Agency. They can also be required on sprinklered homes but judging by by what I can see of where that one is located the home is not sprinklered. It is not uncommon for those to be required to be inspected annually.


  4. #4
    Join Date
    Mar 2007
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    Spring Hill (Nashville), TN
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    5,847

    Default Re: PRV??

    Quote Originally Posted by mathew stouffer View Post
    I have never seen one of these before. Is this a PRV and is it adjustible.
    It is a "check" valve as Jim & Ray noted. Now with that little critter installed you now have a closed system and that requires an expansion tank or valve to be installed. I did not see one in the picture.

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

  5. #5
    Ray Norton's Avatar
    Ray Norton Guest

    Default Re: PRV??

    I would expect to see the expansion tank at the water heater, not at the meter, to absorb the extra pressure caused by the expansion of the heated water.


  6. #6
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    Default Re: PRV??

    Quote Originally Posted by Ray Norton View Post
    I would expect to see the expansion tank at the water heater, not at the meter, to absorb the extra pressure caused by the expansion of the heated water.
    True, for some reason I thought the WH was under the meter in that picture. I think I need to lay off the chocolate chip cookies for my afternoon snack!

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

  7. #7
    Join Date
    Mar 2007
    Location
    Columbus GA
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    3,746

    Default Re: PRV??

    "That's a double check..."

    Close.
    Thats a "Duel check valve", they are not the same as a double check.

    "It is not uncommon for those to be required to be inspected annually."
    Duel checks are not able to be tested, therefore they are not inspected.
    Double checks can be tested and are inspected annually.

    But both do serve the same purpose.

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

  8. #8
    James Duffin's Avatar
    James Duffin Guest

    Default Re: PRV??

    Quote Originally Posted by Ray Norton View Post
    I would expect to see the expansion tank at the water heater, not at the meter, to absorb the extra pressure caused by the expansion of the heated water.
    Since the code in NC now requires a backup drain pan under an expansion tank under same conditions one is required for a water heater I am seeing more expansion tanks in crawl spaces.


  9. #9
    mathew stouffer's Avatar
    mathew stouffer Guest

    Default Re: PRV??

    James is that new in the 09 irc


  10. #10
    James Duffin's Avatar
    James Duffin Guest

    Default Re: PRV??

    Quote Originally Posted by mathew stouffer View Post
    James is that new in the 09 irc
    In NC an expansion tank is considered a hot water storage tank so the following code applies.


    504.7 Required pan. Where water heaters or hot water storage
    tanks are installed in: (a) remote locations such as a suspended
    ceiling (b) attics (c) above occupied spaces or (d) unyentilated
    craw
    I spaces the tank or water heater shall be installed in
    a galvanized steel pan having a minimum thickness of 24 gage,
    or other pans approved for such use.
    Exceptions:
    L Electric water heaters may rest in a high-impact plastic
    pan of at least lL16 inch (1 6 mill) thickness

    2. Water heater mounted on concrete floor for floor
    ~
    504.7.1 Pan size and drain. The pan shall be not less than
    1.5 inches (38 mm) deep and shall be of sufficient size and
    shape to receive all dripping or condensate from the tank or
    water heater. The pan shall be drained by an indirect waste
    pipe having a minimum diameter of 0.75 inch (19 mm). Pip- I

    ing for safety pan drains shall be of those materials listed in
    Table 605.4.


  11. #11
    R.A .McBride's Avatar
    R.A .McBride Guest

    Default Re: PRV??

    Quote Originally Posted by James Duffin View Post
    Since the code in NC now requires a backup drain pan under an expansion tank under same conditions one is required for a water heater I am seeing more expansion tanks in crawl spaces.
    What code is N.C. under?


  12. #12
    James Duffin's Avatar
    James Duffin Guest

    Default Re: PRV??

    Quote Originally Posted by R.A .McBride View Post
    What code is N.C. under?

    The 2009 NC Plumbing code is based on the 2006
    International Plumbing Code with NC amendments.



  13. #13
    Tom Thompson's Avatar
    Tom Thompson Guest

    Default Re: PRV??

    Quote Originally Posted by Scott Patterson View Post
    True, for some reason I thought the WH was under the meter in that picture. I think I need to lay off the chocolate chip cookies for my afternoon snack!
    Scott; Installations of expansion tanks require check valves on cold inlet to heaters making the hot system closed it's self.


  14. #14
    Join Date
    Oct 2010
    Location
    Luxemburg, Wisconsin
    Posts
    35

    Default Re: PRV??

    Says right on it......... Check Valve, the technical term for a backflow preventer.

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  15. #15
    Zibby Bujno's Avatar
    Zibby Bujno Guest

    Default Re: PRV??

    Its BFP (baclflow preventer) - this particular model usually is installed at closed hydronic systems (forced hot water) and water makeup line. Since its installed on main water feed for the house, make sure all water heaters have expansion tank!! Otherwise all PRVs will be leaking.


  16. #16
    Join Date
    Mar 2007
    Location
    Fuquay Varina, NC
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    1,072

    Default Re: PRV??

    James,

    NC amendments., can you post the verbiage because I do alot of new construction and have not yet seen a pan under the expansion tank in an attic or garage.

    Thanks

    Mike Schulz License 393
    Affordable Home Inspections
    www.houseinspections.com

  17. #17
    Tom Thompson's Avatar
    Tom Thompson Guest

    Default Re: PRV??

    Quote Originally Posted by Mike Schulz View Post
    James,

    NC amendments., can you post the verbiage because I do alot of new construction and have not yet seen a pan under the expansion tank in an attic or garage.

    Thanks
    It's recommended by the manufacture, they do go bad. I've had several (most) fail in 2-3 years.


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