What's wrong with my water pressure?? (trying to lower water pressure)

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by CTHaze, May 30, 2021.

  1. CTHaze

    CTHaze New Member

    May 30, 2021
    My house has a pressure regulating valve and a expansion tank above the water heater. House was built in 2000.

    I'm trying to lower my water pressure which currently reads 82 psi when idle.

    When I run the kitchen faucet it falls to 50 psi and when I shut it off it then slowly climbs (I hear a faint water flowing sound even though nothing is turned on), takes about 3 min to get to 60 psi, 6 min to get to 70 psi, and 9 min to get to 80 psi again and the water flow sound stops.

    If I do the same thing with the kitchen faucet to get fall to 50 psi, and go shut off the cold water intake right before the expansion tank at the water heater, the pressure would immediately jump to 80 psi.

    Is this normal?? Any idea what has failed???
  2. breplum

    breplum Member

    Oct 2, 2004
    Plumbing and heating contractor
    San Francisco Bay Area
    The PRV (pressure reducing valve) has failed. This is VERY common.
    Many mfrs make rebuild kits but from my personal experience over 40 years, they are not that easy to rebuild and at least twice, the rebuild didn't end up with a fixed PRV.
    Better to replace with a model that has double unions, like Wilkins NR3XLDU or if on a budget the 70XLDU.
    With double union model in place, swap outs are so easy.
    Jeff H Young, Bannerman and fitter30 like this.
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    Jeff H Young, Bannerman and fitter30 like this.
  4. Jeff H Young

    Jeff H Young In the Trades

    Feb 27, 2020
    I've rebuilt but not really worth it. last time the reg was an 1 1/4 and only around 3 years old. I'm not considering rebuilding 20 year old ones.
    CThaze yes common problem just one of those things don't know how to avoid perhaps if pressure is real high consult manufacture they might suggest 2 regulators but I've never done that
    MASTERPLUMB777 likes this.
  5. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Sep 2, 2004
    Retired Systems engineer for defense industry.
    New England
    Some of the regulators have a maximum differential, and while rare, you might have to step it down in steps with more than one in series. If it was working since 2000 and now has stopped, as others have said, it's likely shot...on a 20-year old one, rebuild is not all that useful, if you can find the kit at all.
    Jeff H Young likes this.
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