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Pressure Regulator Valve broken?

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  • Pressure Regulator Valve broken?

    20 year old house. I am the 2nd owner. Bought the house in May 2008.

    There is a Cash-Acme EB-86 PRV just behind a gate-valve house shutoff-valve. Both PRV and gate-valve look original.

    I used a $10 Orbit water pressure gauge from Home Depot and measured pressure on the garden hose bib, which I believe is regulated since the pipe came out of the house and is apparently controlled by the house gate-valve.

    Ok here are the observation:

    1) Static water pressure varies from 90 - 110 psi, depending on the time of the day. I adjusted the screw on the PRV but it did not make any difference.

    2) When a faucet is opened, water rush out, then after five to six seconds, water flow is noticeably reduced, but still at a usable rate. When PRV is adjusted counter-clockwise, water still rush out, but the flow rate after five seconds is reduced, compared with before adjustment.

    3) I am not able to find any water expansion tank in the house. I have not measured the hot water pressure yet as I don't know where to attach the gauge. Hot water from faucet behaves pretty much the same as cold water: water rush out then flow slows after five seconds.

    4) After a faucet is turned off, I can still hear water flowing in the pipe for four or five seconds before it stops. The sound is especially noticeable in the garage where the PRV and house shutoff valve are located.

    From what I read here and elsewhere, it seems that I should keep the static water pressure to at or slightly below 80 psi. So here are the questions:

    1) Is my PRV broken?

    2) Do I need a water expansion tank?

    3) Where was the water flowing to after I turned off faucet? (This question puzzles me a great deal.)

    Thank you so much.

    Last edited by newowner123; 09-17-2008, 12:44 AM.

  • #2
    Re: Pressure Regulator Valve broken?

    the easiest place to attach a pressure gage is either the laundry valves or at the bottom of the water heater drain.

    the static/ non flow should be below 80#. i typically shoot for 65# at the ground level. you will loose approx. 1/2# per foot of elevation rise.

    your regulator sounds like it's on the verge of complete failure. the regulator is creeping up after the water is shut causing the run on noise. when you open a fixture, the pressure drops to the regulated pressure.

    change the regulator and you'll be fine.

    as far as an expansion tank goes. unless you have a back flow preventer or check valve on the system or water meter. you probably don't need one. pressure regulators typically have thermal expansion bypass feature built in.

    nothing wrong with installing one at the cold side near the water heater, but they do have a wear and tear factor.

    phoebe it is


    • #3
      Re: Pressure Regulator Valve broken?

      Thank you so much Rick. I replaced the PRV and the static pressure now is 65 psi. Will test the pressure after heating cycle. (I think it should be fine -- after all, the house endured constant 100 psi all these years without any flooding.)


      • #4
        Re: Pressure Regulator Valve broken?

        Ok so the good news is static water pressure is stable at 55 psi. Bad news is after WH shuts off, thermal expansion pushes that up to 100 psi. Flushing a toilet drops that to 55 psi.

        So if I take a shower and leave house for work, the pipes are going to endure 100 psi for the whole day. Would all you experts agree a thermal expansion tank is needed?


        • #5
          Re: Pressure Regulator Valve broken?


          it sounds like there is a check valve somewhere on the system locking in the pressure.

          so a thermal expansion tank is your way to correct this.

          phoebe it is


          • #6
            Re: Pressure Regulator Valve broken?

            Thermal expansion tank or a prv with a bypass relief.