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Discussion Forum

Water pressure regulator – proper size??

jps | Posted in General Discussion on December 29, 2004 03:33am

Hello all,

Long story short – HD only has one make/model/size of pressure regulator. So I now have a 3/4″ Watts Pressure Reducing Valve. My concern is that I don’t have the right size. It is physically about half the size of my current regulator. I really hate doing the same job twice (or worse) – which is why I am asking you guys rather than the lackey at HD!

The best information I have found is at http://www.plumbingsupply.com/waterpressureregulators.html#faq where there is a nice chart describing flow rate and pressure drops. However, it doesn’t say what a residential usually requires in flow rates.

I searched the forums and found someone asked the exact same question over the summer, but got no response. You are all a gold-mine of information. I spend DAYS reading the back posts!

Thanks!

PS – Anyone have a personal recommendation of a plumber and/or electrician in the Gwinnett, Ga location?

“One experiment is worth a thousand expert opinions”
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Replies

  1. User avater
    IMERC | Dec 29, 2004 03:41am | #1

    welcome JP

    how many baths...

    what's yer fellings about Piffen Screws???

    how many in yur hosehold???

    what do you prefer..

    tyveck or felt???

    what is the true supply line size into the house..

    is attic vented and is it done that way by choice...

    rural or city water...

    which is yur tool color...

    sprinkler system???

    take a number

    have a seat...

    no cutting the line...

    enjoy yer stay here at BT....

    Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming

    WOW!!!   What a Ride!



    Edited 12/28/2004 7:43 pm ET by IMERC

    1. jps | Dec 29, 2004 04:50am | #2

      IMERC - : how many baths...
      2.5 bath, 2 story
      : what's yer fellings about Piffen Screws???
      Uhm, I'll go with a nail? (I don't know of any other phrase in the world that fails to bring up more than one result on google)
      : how many in yur hosehold???
      2 (+1 shortly)
      : what do you prefer..tyveck or felt???
      Tyveck
      : what is the true supply line size into the house..
      Uhg - it is 3/4 into the crawl space if that is what you are asking.
      : is attic vented and is it done that way by choice...
      Yes and yes (but I can't say the same for the crawl space - that is a different discussion topic)
      : rural or city water...
      City, and it pegs my 80psi meter (on both sides of the current regulator)
      : which is yur tool color...
      grey (I am partial to PC, too many PBS ads I think)
      : sprinkler system???
      Nope, but the regulator is (oddly) after the hose outlets. I burst EVERY hose I have ever put on. The hot water heater PR valve is letting loose a steady stream, one of the toilet valves burst and the pipes are making some funky clunkin'.Since I am laying it all on the table here, I guess I will go the extra mile... For Christmas I got a Tiger Saw (just for fun :), a 12" planer and a DeWalt corded drill (so my son-to-be doesn't learn new words when I use my Grandfathers 1970 B&D drill!)JP"One experiment is worth a thousand expert opinions"

      1. UncleDunc | Dec 29, 2004 05:06am | #3

        >> I don't know of any other phrase in the world that fails to bring up more than one result on google.Most of the rest of us, including Piffin, spell it piffin.There's actually a game called Googlewhacking that consists of thinking pairs of words that result in only one Google hit.

      2. Pierre1 | Dec 29, 2004 05:42am | #4

        That's a lot of pressure failures you've got there JP. Your house supply is probably above 125psi I'd guess.

        'Normal' residential pressures on a municipal system run +/- 60psi. Modern pex supply line and fittings are certified to 100psi but will take a bit more. Diswasher and clotheswasher solenoid valves, toilet ballcock fill valves, etc. will fail much sooner than otherwise at higher pressures. So will your hot water tank's pressure vessel...

        My advice - and I'm not a plumber - is to install a pressure reducer on your 3/4" supply line, asap.

        Edited 12/28/2004 9:54 pm ET by Pierre1

      3. User avater
        IMERC | Dec 30, 2004 02:26am | #12

        I was messing with ya 1/2 the time...

        Search function here for Piffen Screws...

        or go to http://www.piffenscrews.com if the site is still open....

        suggest you aim for 15GPM max + 60PSI....

        you'll find 10GPM is a lot of water...

        move the regulator to begining of the line...

        the one you have is not functioning or incorrectly adjusted...

        Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming

        WOW!!!   What a Ride!

  2. IronHelix | Dec 29, 2004 02:33pm | #5

    And crank it down to under 80 psi......60 is quite nice.(Only, if it is not preset!)

    Consider replumbing your yard hydrants to save hoses. Although there are commercial/industrial hoses that will tolerate 100 psi...but expect to pay up to $2 per foot.

    ...............Iron Helix



    Edited 12/29/2004 6:34 am ET by Iron Helix

  3. dIrishInMe | Dec 29, 2004 03:24pm | #6

    I'm no plumber but will give you an answer since no one else has (IMO) answered you directly about flow rate.  First though... In the .2 post IMERC was just messing with ya - at least half the time :-) 

     A flow rate of 10 GAL Per Minute is ideal at an individual spigot, although most residential systems only deliver about 5 GPM at normal pressure.  Of coarse you want to be able to run more than one spigot at once and still get reasonable flow.  ~50 PSI is standard residential water pressure, although you can safely go to 60 PSI.  Much above 60 PSI and you are looking for plumbing problems.  Most pressure reducers come pre-set.

    Ditto on whoever said that if you present pressure reducer is not working you need to get this fixed ASAP.

    You can test your home's water pressure with a gauge you get form HD or where ever.  I'd guess they are around $12.  It screws onto your hose bib (sill cock - outside faucet - or whatever you want to call it) or you can attach it to your washer cold water spigot.

    To test flow rate just get a 5 gallon bucket and a watch and see how much water you get in 30 seconds.  Test flow rate at a hose bib or from the cold washer hose - not a tub or shower.
     

    Matt
    1. jps | Dec 29, 2004 05:16pm | #8

      Thanks Matt (and others)...

      Assuming 5-10 gpm I think a 3/4 should do nicely.  I will write it out for the next poor sap like me who searches the forum.

      The city pressure is somewhere around 110 psi, so assuming I want it to be 60 psi my differential pressure will be about 50 psi (P1-P2). Since the 'average range' can be as low as 45 psi, that means the P2 Variation (loss of house pressure) can be up to 15 psi.  According to the chart, that gives me a flow rate of about 22 gpm.  Best case, I should only see about a 5 psi loss of house pressure when using 7.5 gpm.

      (Note the chart and terminology is from http://www.plumbingsupply.com/waterpressureregulators.html#faq )

      Thanks again!

      JP"One experiment is worth a thousand expert opinions"

      1. User avater
        BillHartmann | Dec 29, 2004 07:00pm | #9

        You also need an expansion tank.It is a small tank that has an air chamber.With the PRV (pressure reduction valve) if you use lots of hot water and and then stop. The WH tank will have lots of cold water. Then as the WH heats it up it will try to expand and with the PRV it can expand back into the city mains.Thus the pressure will increase until the WH safety release water.

    2. DanH | Dec 29, 2004 08:21pm | #10

      To properly test the flow rate you should open up at least two faucets, measure the flow rate of both, then add them together.

      1. User avater
        IMERC | Dec 30, 2004 02:20am | #11

        you mean average don't ja...

        Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming

        WOW!!!   What a Ride!

        1. DanH | Dec 30, 2004 02:28am | #13

          Nope.

          1. User avater
            IMERC | Dec 30, 2004 02:51am | #14

            add???

            ya still sure....

            Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming

            WOW!!!   What a Ride!

          2. DanH | Dec 30, 2004 05:01am | #15

            Yep, still sure. If you want max flow rate you gotta assume that more than one faucet is in use at a time.

          3. dIrishInMe | Dec 30, 2004 05:30am | #16

            Makes sense to run 2 or more spigots to see how the water delivery system acts "under load".  Good pint.  On the other hand, it doesn't make any sense to add the flow rates together - granted 2 people (or more) could be using spigots at the same time, but when is one person going to be using more than one spigot at a time? Not!  Following your logic I guess all spigots & water using devices in the house should be turned on at the same time, and each measured and then all added together.  Everybody is entitled to their opinion though... Matt

          4. DanH | Dec 30, 2004 06:12am | #17

            You need to size the regulator for the max "normal" flow. If only one person lives in the house, then only one faucet is OK, but if you don't want to have a big pressure dip when someone flushes the toilet while you're showering, you need to size for more flow than that.

          5. Pierre1 | Dec 30, 2004 01:55pm | #18

            Dan, isn't this a 3/4" house main situation...which pretty much dictates the flow capacity?

            The owner is not upsizing his house main, or the main trunk lines in the house. He simply needs to reduce the pressure to where there won't be any more damage from overpressure. A WP reducer with 3/4" inlet and outlet will surely yield a serviceable water flow, if the pressure is set at 60 psi.

            If maintaining high pressure at the outside hose bibs is desirable, they can easily be replumbed so that their feed Ts off the water main, downstream of the main shut-off but upstream of the WP reducer.

          6. dIrishInMe | Dec 30, 2004 02:58pm | #19

            You are correct about the 3/4" main, etc.  All this talk about flow rates got started because the original poster was looking at specs for various pressure reducers.  I think maybe he was suffering from a classic case of a little to much information (specs) available, and a bit of over analysis.  On the other hand, if he had available to him a pressure reducer with a published flow rate of 2 GPM and another with 50 GPM - which to pick? - having no idea of what might be a normal residential GPM load.  I think he now has that information and at this point the conversation is more academic than anything.  

            Inquiring minds want to know...  Matt

          7. DanH | Dec 30, 2004 08:41pm | #20

            Yep, the house main will pretty much dictate flow rate. But that doesn't mean that a 3/4" regulator is necessarily sufficient (though one would generally assume that it would be). And the question I was addressing was how to determine flow rate, not whether the typical 3/4" regulator should be sufficient.BTW, around here it's SOP for the incoming water line to be 7/8", and only reduce to 3/4" at the service stop just inside the house.

          8. User avater
            IMERC | Dec 31, 2004 01:59am | #21

            that's true...

            but I believe it's still averageing the two to gether to get the GPM rate....

            Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming

            WOW!!!   What a Ride!

          9. DanH | Dec 31, 2004 02:50am | #22

            No. Think about it. You have two people using water. One is using 3 gallons/minute, and the other is using 2 gallons/minute. The total flow rate if 5 gallons/minute.

          10. User avater
            IMERC | Jan 01, 2005 05:40am | #23

            otay

            Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming

            WOW!!!   What a Ride!

  4. TRice | Dec 29, 2004 05:08pm | #7

    Talk to the folks at Ferguson. (404) 495-9919

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