What is the correct water pressure for our house?

Discussion in 'Plumbing Forum' started by oldpops, Feb 26, 2019.

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  1. Feb 26, 2019 #1

    oldpops

    oldpops

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    Hi All! I have posted before about the water hammer noise in our home (started with one toilet, then both, then the clothes washer), and the noise has been getting progressively worse. Thought about just buying a water hammer arrestor, but since the sound is getting progressively louder, and after some good advice here, i am looking at the pressure regulator (PRV)at the front of the house . Incidentally, we don't have an expansion tank in our southern California home built in 2002, but the inside plumbing is all a PEX system.

    Put a gate water pressure gauge on the water spigot just, which is just before the 3/4 inch pipe goes into the house. Here is where I am a bit confused: What exactly should the water pressure be at?? Some say 30 to 50 PSI, some say 40 to 60 PSI. A few you-tube videos made by plumbers say 70 or even 80 PSI is OK?? So which is it?

    In our case, I am getting a base pressure of 70 PSI (black needle), and the red needle (MAX pressure) shows 100 PSI. My understanding is that the black needle shows the static pressure, and the red needle shows the most the water pressure PSI has been since it was last reset - Is that correct?, If so, is the fact the the max pressure is 100 PSI, even if only for a short time, does that mean there is a problem with the water pressure? Or is it normal to have pressure spikes and that i should only care about the base pressure?

    Finally, if the consensus here is to adjust, and if need be: to rebuild or replace the valve, (Watts LFN45B), how do I do that? I know to adjust the pressure (by screwing in/out the screw), but how do i open up the valve to rebuild it. The rep at Watts gave me the part number (0006960), which doesn't include the diaphragm or big spring, just a black plastic thing with a screen on it, along with two o-rings. However, I don't know if there is a rebuild kit that replaces all the guts inside. Does anyone know if there is one?

    Let me thanks in advance to all who offer help or advice.
     
  2. Feb 26, 2019 #2

    maxdad118

    maxdad118

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    A pressure regulator should maintain a set pressure regardless of how many faucets or showers are on. If it goes from 60 to 100 psi that, to me, is not right.
     
  3. Feb 27, 2019 #3

    Snoonyb

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    Do you know that it is, and less confusing, and simpler, to follow a subject under a single thread title, rather than multiples.

    What city are you in, so I can find a supplier for you, that you can visit and have the regulator explained?
     
  4. Feb 27, 2019 #4

    havasu

    havasu

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    Many cities, including my own city, will replace all pressure regulators for FREE, just by contacting the water company. It is a way to conserve water. Make some phone calls, and get this replaced.
     
  5. Feb 27, 2019 #5

    oldpops

    oldpops

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    Hi everybody, and thanks for all the advice. I am kind of an old guy and not to good on computers so I sometimes make . I did start another thread on water hammer and hammer arrestors, and got some great advice. Now that I am zeroing in on the PRV, I didn't mean to cause any confusion, I just thought it best to start a new thread just to concentrate on the PRV. Even for an old guy, I do learn a lot on this forum and certainly appreciate every suggestion and all input. I am in southern California, near Corona. I found a Ferguson store located near-by and I am going to give them a call
     
  6. Feb 27, 2019 #6

    oldpops

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    Called the local Ferguson store & they put me on with a sales rep. He told me he couldn't give any info on fixing/rebuilding the valve. Called Watts and support tech gave some instructions on installing a rebuild kit but then said it would be best to replace the valve. $$$ I don't have.
     
  7. Feb 28, 2019 #7

    havasu

    havasu

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    Heck, ol pops, you are just down the road from me! You can get a new PRV at Home Depot for $85.
     
  8. Feb 28, 2019 #8

    slownsteady

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    You didn't mention whether you are on well water or city water ( I think we can assume city water).

    And if Havasu is nearby, and he is able to get a free regulator from the city, then it is a good chance that you can too.
     
  9. Feb 28, 2019 #9

    oldpops

    oldpops

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    i will certainly try that! Thank you all!
     
  10. Feb 28, 2019 #10

    billshack

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    the correct pressure to set a PRV is 65 to 70 lbs. canadian plumbing code .
     
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  11. Feb 28, 2019 #11

    Diehard

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    First off, the common PRV's used in a home are direct acting types and not pilot-operated valve types.
    The direct acting type does lose pressure as flow increases.
    A pilot operated type senses the downstream pressure and makes adjustments to maintain the set pressure with varying flow rates.
     
  12. Feb 28, 2019 #12

    Diehard

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    It would be good if you were able to determine when the pressure increase to 100 psi occurred. It's possible to be the result of water hammer since water hammer can cause extremely high pressures.

    Water hammer is based on the sudden change in velocity of the water moving through the pipes. And it's sometimes amplified by loosely supported pipe. The higher the pressure the higher the velocity and/or the higher the results of a sudden change in the velocity.

    For a first step, I would adjust the typical 70 psi down to 60 psi.(Oh, and yes the red needle would typically be momentary high reading. Reset the red needle.)
    Keep in mind that water hammer can occur even with 40 psi or less. If you have a fast closing valve, such as the typical solenoid valves on a washing machine, and still have water hammer, you could either add water hammer arrestors at the machine or could could try throttling the water feed at the valves feeding the washer.
    You can go lower but depending on your particular water needs and number of stories, you may not like the lower pressures and flows. Go as low as you want , as long as you're still happy with the results at your fixtures.

    EDIT: To reduce the pressure loosen the lock nut and turn bolt counter clockwise.
    n45bdu-tif.jpg
     
    Last edited: Feb 28, 2019
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  13. Feb 28, 2019 #13

    Diehard

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    I don't feel replacing or rebuilding your PRV should be your first step.
    Makes me think of some car mechanics that replace parts without knowing what the problem is for sure.
     
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  14. Feb 28, 2019 #14

    oldpops

    oldpops

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    Well, I hope to get into the two attics we have today and strap down the piped. Then adjust the PRV pressure down to 60 and see how that does. After that, I plan on getting a chair and watching the pressure gauge and have my wife turn on/off all the faucets, showers, tubs, flush toilets (one at a time) and the clothes washer to see if i can isolate when the needle does its jumping.
     
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  15. Feb 28, 2019 #15

    Diehard

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    Don't lose too much sleep watching that gauge.:D

    I just this minute received a pressure gauge in the mail. It's Rainbird gauge made it China so I have no idea how actuate it is. Just tested my static pressure at my washing machine connections and I'm reluctant to believe it but it read 90 PSI. I don't feel that my pressure is that high. I'll do some residual pressure tests(flowing) to see how much pressure I lose when flowing different amounts at different locations. I have mostly 1/2" piping, so I know I lose a lot of pressure when I have things flowing wide open.

    I never experience any water hammering.
     
  16. Mar 2, 2019 #16

    pjones

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    Are you on a water meter or have a check valve installed somewhere in the line?

    Hydrostatic expansion can cause your pressures to increase up to 100 easily if there is nowhere for it to expand. PEX has some give to it so the pressure jump wouldn’t be quite as drastic as you would get with a copper pipe house, but you will still see an increase with no fault to the PRV.
     
  17. Mar 12, 2019 #17

    Diehard

    Diehard

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    OP mentioned that he didn't have an expansion tank.
    If he has a water heater subject to expansion, such as a tank type, then he should have an expansion tank.

    The Watts PRV literature claims, "The standard bypass feature permits the flow of water
    back through the valve into the main when pressures, due to thermal
    expansion on the outlet side of the valve, exceed the pressure in the
    main supply."


    But on the other hand it also states, "The bypass feature will not prevent the pressure relief valve from opening on the hot water supply system with pressure above 150psi (10.3 bar)."

    That last statement can be interrupted different ways but the way I see it, it's possible that the bypass feature may not be capable of releasing the increased pressure quick enough, in which case you should have an expansion tank on the cold water side of a tank type water heater. (Roughly a $50+/- item, plus installation.)

    Anything new yo report on RPV?
     
  18. Apr 15, 2019 #18

    Jim greengo

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    I'd screw it on to an outside faucet and open the valve to see what you have for pressure.
    Anything much over 70psi will cause problems with pop off valves on water heaters,and fluid masters on toilets.
     

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