I had a PRV installed horizontal at my house and my permanently installed pressure gauge showed a baseline supply pressure at about 60 PSI.

I merely changed the orientation of the PRV to be mounted vertically and now the baseline pressure seems to be 40 PSI. Does this seem like the plausible cause of the drop in pressure to you?

  • NO, it does not explain it
    – Traveler
    Jun 2, 2022 at 2:36
  • Were there changes in the plumbing that lead to being able to install the valve in a different orientation? Maybe extra elbows reduced the flow (though 20PSI is significant). Is it attached to PEX that may have been pinched when changing direction?
    – FreeMan
    Jun 2, 2022 at 12:15
  • 2
    So, turn it back up...? Seems most likely the adjustment was inadvertently altered in handling. They are adjustable. Adjust it.
    – Ecnerwal
    Jun 2, 2022 at 12:34

1 Answer 1


A PRV is simply a pressure regulator.

When you moved things it may have moved the spring into a slightly different position changing the pressure as you observed.

The other possibility you bumped the adjustment screw (but these usually take a few turns for that large of a shift).

In either case it’s no big deal just turn the adjustment screw usually tighter is higher pressure watch your gauge while increasing and go slow remember the pressure may be slightly lower with a flow if you set it at static or no flow. If you set it with flow the static may be higher.

There should be a jamb or locking nut on the screw shaft, loosen this prior to adjustment and tighten after, the pressure may also change when the lock nut is tightened, if a plastic handle type knob some pull out to unlock and then push back in to lock.

  • 2
    Might also have dislodged some stuff caught in the internal filter, if (as in many) it has one of those integrated - could be worth disassembling and cleaning as per documentation, if so.
    – Ecnerwal
    Jun 3, 2022 at 20:03
  • @Ecnerwal that’s definitely something I have to check. I just can’t prioritize it right now. It’s basically move-in day. Jun 3, 2022 at 21:04
  • I would try adjusting it that only takes seconds.
    – Ed Beal
    Jun 4, 2022 at 4:11

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