Can PRV adjust to 0 psig?

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by droptail, Jan 26, 2014.

  1. droptail

    droptail New Member

    Messages:
    5
    Location:
    CA
    Can I temporarily adjust my Zurn Wilkins 600 pressure reducing water valve for no house water pressure?

    Thanks
    Last edited: Jan 26, 2014
  2. Jerome2877

    Jerome2877 In the Trades

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    397
    Location:
    BC
    Most PRV's go from 25-75 psi and come set at 50 psi. 0 psi would be shut off, not what a PRV is designed for.
  3. droptail

    droptail New Member

    Messages:
    5
    Location:
    CA
    Its unclear if you have answered my question.
    I know what they are designed for.
    I am asking if it is physically possible to remove the adjustment screw and get zero flow.
  4. Jerome2877

    Jerome2877 In the Trades

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    397
    Location:
    BC
    No, the lowest it will go is 25 psi. You use a shut off valve to do what you want.
  5. Gary Swart

    Gary Swart In the Trades

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    Common sense should tell you that you should have a shut off valve where the water supply enters the house. Preferable a 1/4 turn ball valve. You never know when you could have a broken pipe and need to shut the water off quickly.
  6. DonL

    DonL Jack of all trades Master of one

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    Houston, TX

    Some PRVs can go down to 0 , but as stated that Model should not.

    You should have a shut off at your meter, And some Big Box stores have the tool that fits the valve. Or you can call the water company.


    Good Luck.
  7. hj

    hj Moderator & Master Plumber Staff Member

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    Normally, if something, such as corrosion, destroys the spring compression of the adjuster, the system pressure WILL drop to zero. If yours will, then just remove the adjusting bolt. The answer to your question should be intuitive.
  8. DonL

    DonL Jack of all trades Master of one

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    I can see if the spring is broke then the water would be shut Off.

    But a Good Spring will hit the top of the housing, even if the screw is removed.

    If it was mine, I would just try it, but I have 2 water shut off locations, so really no need.

    I can say I have never owned that model. If I had one I would test it to see if the Manufacture tells the truth in their spec sheet.


    Try it just for Grins, Then report back about how everyone and the manufacture is wrong.
  9. droptail

    droptail New Member

    Messages:
    5
    Location:
    CA
    Thank you for your responses.

    The handle for my shut off had rusted and broke off, so that wasn't an option until I loosened up the ball valve.

    It seems to me now after my investigation that its probable the spring is always minimally compressed enough to hold spring assy in place if the screw is removed, hence the minimum operating pressure of this design.
    It didn't feel like there was any spring press when installing the screw housing, but the old spring may be slightly collapsed/fatigued.
    I can't say for sure until I extract the broken screw, or replace unit.

    Not such a great design to allow the stem washer wear to put the house in supply line (high) pressure without ever knowing it.

    I will try and remember and report back.

    Thanks again.
  10. DonL

    DonL Jack of all trades Master of one

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    That is what I was thinking, and your are correct.

    Good Luck on your project.
  11. Gary Swart

    Gary Swart In the Trades

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    My suggestion on the shut off valve is of course in addition to the meter shut off. In my city, they "discourage" homeowners having a key to shut the water off at the meter. I have one anyway, but I still have a quarter turn ball valve in my basement where the supply line enters the house. If I have trouble in the middle of winter or late at night, I don't relish the idea of going out the street and digging the snow off the meter's manhole. If I have a problem with the supply line, then the meter shut off is necessary. Just a suggestion, but for next to nothing, why not?
  12. DonL

    DonL Jack of all trades Master of one

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    Not sure why the city would frown or discourage a homeowner having the tool to shut it off.

    If they shut you off for not paying the bill, and you turn it back on, then they will know it. The meter will read usage.

    If you do not pay your water bill they will shut it off for you, no need to have a tool.


    I am lucky so far, I would not want to live in the city limits.
  13. Jerome2877

    Jerome2877 In the Trades

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    Location:
    BC
    Its a liability thing, if you break the valve then your responsible.
  14. bluebinky

    bluebinky Member

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    Location:
    Santa Clara, CA
    The local water guys here want to be around if something breaks. Especially this year since it's rained maybe an inch since last May.

    They do prefer you have a tool in case of an earthquake or whatever.
  15. Caduceus

    Caduceus Master Plumber

    Messages:
    136
    Location:
    Pittsburgh, PA
    Funny, I started reading this thread and had to reply before finishing cause I got a good chuckle. PRVs don't go to 0. Otherwise it's just called a 'valve' for this application and the 'PR' can be removed from the equation.
  16. Caduceus

    Caduceus Master Plumber

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    136
    Location:
    Pittsburgh, PA
    Local water companies will fine and restrict non-authorized persons for tampering with curb valves because people have shut off the water and added separate water feeds before the meter. Some folks still try to engineer themselves around this with home made tools and that is why most newer water meters have a backflow sensor that will pick up flow before the meter.
    Stealing water is more common than you may think and the utilities are always working on a better mouse trap.
  17. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
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    Location:
    Cave Creek, Arizona
    Why CAN'T a "PRV" adjust from ZERO to "maximum" and still be called a PRESSURE REGULATING valve?
  18. DonL

    DonL Jack of all trades Master of one

    Messages:
    4,331
    Location:
    Houston, TX

    No reason that they can't, because they do make them that go to 0.

    But the model in question is not rated to go below 25 PSI.

    It may do it, but the pressure may not regulate to its pressure setting.
  19. Caduceus

    Caduceus Master Plumber

    Messages:
    136
    Location:
    Pittsburgh, PA
    Because I was jerking him around, that's why. The OP made the make and model clear and we knew the adjustment parameters. Once Jerome finally answered the question and mentioned the valve before the regulator, everything else that followed started to sound redundant and repeated itself. Until the OP volunteered the "why" of the situation, nobody bothered to ask, since it is a rather odd question to start.
    It's just funny how one person can follow another and continue to repeat the same thing but with the words in different order and act like it's an original thought. My statement was to provoke the members following the thread to see how much useless repetition would continue.
  20. droptail

    droptail New Member

    Messages:
    5
    Location:
    CA
    In follow-up as promised.

    The reason this PRV does not adjust to an off condition is because the seal is forced open by inlet pressure until enough outlet pressure builds up to close it via diaphragm assy. This equilibrium occurs at 25psig.
    Diaphragm controls the closing, not the spring. The spring can be adjusted to apply zero pressure on the diaphragm.

    Thanks for the reply's.
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