Water pressure regulator problem – pressure increases overnight

Discussion in 'Plumbing Forum, Professional & DIY Advice, Tips & ' started by igornys, Oct 9, 2013.

  1. igornys

    igornys New Member

    Messages:
    14
    Location:
    New York
    I recently discovered that water pressure in my house it too high and tried to adjust it on the water pressure regulator.

    The problem is that the pressure that I set at 50psi increases to about 80 if I check it as the first thing in the morning. I assume that there is a ‘leak’ inside the regulator and pressure rises when there is no water drain/consumption inside the house.

    As the outside pressure in our area reaches 180psi, I am considering fixing or replacing regulator to be on the safe side.

    - Would you recommend to try fixing it?
    - I see very similar looking Watts units, would you recommend using it as a replacement?





    Regulator.jpg
    Last edited: Oct 9, 2013
  2. Gary Swart

    Gary Swart In the Trades

    Messages:
    7,298
    Location:
    Yakima WA
    The majority of opinions on this forum about faulty PRVs is to replace them. Judging by the rust, yours appears to be quite old, and while repairs might be possible, I doubt if it would be worth the time and parts to do it. You have a Watts, and that is a reliable brand.
  3. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,802
    Location:
    New England
    Another thing to look carefully at: the maximum pressure differential allowed on the PRV. Dropping from 180 to 50 means a differential of 130#. You may need TWO PRV's, plumbed in series to reliably reduce that pressure. Read the specs very carefully.

    With a PRV in the system, your house is what's considered a closed system, and must have an expansion tank in it. If you don't have one OR the one you have has failed, the pressure in the house will rise after any significant hot water usage when the water heater reheats all that cold water and it expands.
  4. Reach4

    Reach4 Active Member

    Messages:
    1,885
    Location:
    IL
  5. dj2

    dj2 Member

    Messages:
    398
    Location:
    California
    Another vote to replace it.
  6. Reach4

    Reach4 Active Member

    Messages:
    1,885
    Location:
    IL
    Whether you replace the valve or not, you need the expansion tank. A regulator/PRV with "Thermal Expansion Bypass Technology" is not going to change that since you have unusually high input pressure.

    I suggest you crack open a faucet a tiny bit. If the pressure drops to what the regulator is supposed to be adjusted to, I think it is very likely that the regulator is fine.

    I vote to just add the expansion tank until there is a symptom that a regulator might cause. Nobody is going to vote that you not add an expansion tank.
  7. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,802
    Location:
    New England
    As I said, if you don't have an ET - OR the one you have has failed, you should add one and this may solve your problem. With that high of an incoming water pressure, the PRV may not work, or work very long with that large of a pressure differential, which is why, in some cases, you need two, each one dropping the pressure part way to achieve a stable value and not wear out or fail quickly. The seals and springs in the thing have limits...you may be exceeding them.

    Also note that it is not uncommon for the system supply pressure to rise at late night when they are refilling reservoirs and towers. That, combined with little use, can mean the pressure at late night is quite a bit higher, stressing the PRV even more.
    Last edited: Oct 9, 2013
  8. igornys

    igornys New Member

    Messages:
    14
    Location:
    New York

    ... my journey started in a different thread some time ago – now I do have a working expansion tank.

    It is good to know that there is a maximum pressure differential allowed on the PRV. It looks like this LF25AUB-Z3 Watts units will perfectly handle it.

    Now another question – the regulator is installed in a place that is difficult to access. I am now considering calling a professional plumber or using a push-in fitting like “sharkbite”.

    What would you recommend?
    Last edited: Oct 9, 2013
  9. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,802
    Location:
    New England
    Sharkbites work if you prep the pipe properly (i.e., a square clean cut and deburr the edge). This is important, or you may damage the O-ring, which is what creates the seal. Soldering things in is more robust, as things won't rotate with a soldered connection, while they can with a Sharkbite. You can't solder if there's still water in the pipes, so that can make the push-on fitting quicker and easier, but they are more expensive than a conventional fitting.
  10. Gary Swart

    Gary Swart In the Trades

    Messages:
    7,298
    Location:
    Yakima WA
    I would not use a Sharkbite for this. Maybe they would work and be dependable, but I'd sure want a sure solid connection. Sharkbites are designed for DIY. I doubt if a real plumber would even consider their use. The PRVs I am familiar with have a union fitting on one end, and I'd install a new PRV using at least one union.
  11. igornys

    igornys New Member

    Messages:
    14
    Location:
    New York
    I would also prefer to solder, however, as I mention before the PVR is mounted the way that it is very difficult to access/solder. In this case I will not trust myself to do it as DIY job unless I use “sharkbite” or similar (even if it would be possible to re-use the existing union on one side).

    As for the price for “sharkbite” – in my case price for the two connectors (I guess about $30), will be still much less than calling a plumber (I guess, $100+)
    Last edited: Oct 10, 2013
  12. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,802
    Location:
    New England
  13. igornys

    igornys New Member

    Messages:
    14
    Location:
    New York
    I would rather consider Watts PRV + SharkBite connector on one side (I will be probably able to re-use existing union on another side).

    Do you know if Sharkbyte are permitted for that kind of work?
  14. valveman

    valveman Moderator Staff Member

    Messages:
    4,369
    Location:
    Lubbock, Texas
    Even new PRV's have what is called "creep". If they sit long enough, some of the high pressure on the inlet side will "creep" through the seat and increase the pressure on the discharge side. Without an expansion tank it only has to "creep" through about a thimble full of water to greatly increase the pressure. The expansion tank should hold 1/2 gallon, and prevent the pressure increase from "creep" and from thermal expansion.
  15. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,249
    Location:
    Cave Creek, Arizona
    quote; I suggest you crack open a faucet a tiny bit. If the pressure drops to what the regulator is supposed to be adjusted to, I think it is very likely that the regulator is fine.

    That is the test for a FAUTLY regulator to see how quickly the pressure increases, BUT, a faulty regulator would normally keep rising until the pressure was equal to the upstream side, although it may NOT be as high as you stated.
  16. dj2

    dj2 Member

    Messages:
    398
    Location:
    California
    I'm sorry but I don't see a difficult job here, cutting the pipe, removing the PRV and installing a new one. If it's between choosing sharkbites or calling a plumber, go with the 2nd choice.
  17. igornys

    igornys New Member

    Messages:
    14
    Location:
    New York
    I do have ST-12 expansion tank, this is a lot of volume to fill in, also if the water “creeps” through the seat the actual flow will gradually decrease with the increasing of the house pressure.

    As for the pressure in the “upstream” – it was 150psi this morning, almost90 psi inside the house.
  18. igornys

    igornys New Member

    Messages:
    14
    Location:
    New York
    As I mentioned already, the place is not completely open and difficult to access. In addition I will need to drain water that will be not easy keeping in mind location.
  19. igornys

    igornys New Member

    Messages:
    14
    Location:
    New York
    As for now, having water dripping from a faucet slowly solved the problem – the pressure now stays at 50 psi.

    I will go ahead replacing PVR - would you recommend any specific brand/model?
    Last edited: Oct 11, 2013
  20. igornys

    igornys New Member

    Messages:
    14
    Location:
    New York
    What replacement regulator would you recommend?

    The one I have installed looks similar to modern Watts LF25AUB-Z3 regulator and High-performance Watts LFU5B-Z3.

    I was also looking to Zurn-Wilkins 34-70XLDUC that in my case will be easier to install because of the unions on the both side.
Similar Threads: Water pressure
Forum Title Date
Plumbing Forum, Professional & DIY Advice, Tips & Low water pressure at one shower but not the other Jul 6, 2014
Plumbing Forum, Professional & DIY Advice, Tips & Low Cold Water Pressure in Entire House Jun 18, 2014
Plumbing Forum, Professional & DIY Advice, Tips & New home - 85 psi water pressure Jun 4, 2014
Plumbing Forum, Professional & DIY Advice, Tips & Very low water pressure after replacing kitchen faucet and no hot water in shower May 15, 2014
Plumbing Forum, Professional & DIY Advice, Tips & too much water pressure Apr 29, 2014

Share This Page