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Can't stabilize water pressure

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  • Can't stabilize water pressure

    Dang. I installed a Zern 70DUC (reduced range: 25 to 75psi) regulator while rebuilding incoming water from bib down. It's factory set at 50psi and it stayed that way for about 30 minutes while I was cleaning up. I increased it to 60, but within about 20 minutes my gauge was reading about 110psi at the bib. I backed it back to 50psi, but the Customer called stating that there is very low pressure upstairs. I realize pressure can fluxuate greatly throughout the day. I'd rather not have my Customers running over 100psi (downstairs) if I can help it. Obviously they need the extra pressure upstairs. 4 Bedroom, 3 bath and approx 2,500 sq feet.

    What am I missing? Or do they just live with high pressure periodically?

  • #2
    Re: Can't stabilize water pressure

    If you are seeing 100 PSI on the house side, something is missing from the equation. The regulator cannot do that, unless it is broke. You didn't mention the timing of these readings, so we don't know if a water heater expansion issue is involved. Please provide more details.


    • #3
      Re: Can't stabilize water pressure

      Something is wrong with this picture!


      • #4
        Re: Can't stabilize water pressure

        it's either thermal expansion or a leaking cartridge in the regulator.

        easiest way to tell is turn down the water heater.

        the range is up to 75#.
        110# beyond the designed range. so it's either a bad regulator or thermal expansion.

        by the way, pressure loss due to elevation is only .43# per foot. so your 100# on the first floor is 95# on the second. still way too high.

        test the heater and see if it's thermal expansion or a leaking regulator.

        phoebe it is


        • #5
          Re: Can't stabilize water pressure


          Rick has some good thinking here. Try shutting off your water heater and note the water pressure over several hours with all valves closed. You either have a leaking pressure regulator or a thermal expansion issue. With your water heater off it should be easy to determine if the regulator is bad.

          If you have the gauge before the water heater, you can shut it totally off, (be sure it really is off) and then close the inlet valve and note pressure.

          Where are you measuring your water pressure for now?

          I think I see the need for a few pictures. Please do not close the inlet (fill) valve to a water heater until you first are sure it really is OFF.
          Last edited by Woussko; 02-17-2009, 11:39 AM.


          • #6
            As it turns out...

            I suspect that the regulator was played with before purchase. The set bolt, presses against a convex washer that in turn compresses or decompresses the spring. Without the washer, the bolt just slides inside the spring and has no effect. If the bolt is backed off to much, the washer just falls off. I took the housing cap off and reassembled. Whatya know, it works like a charm. I don't know why I didn't think of it sooner. Another brain fart episode.

            Thanks folks!
            Last edited by JeffH; 02-17-2009, 07:21 PM.