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Enlarging shower valve, more flow rate?

sixfingers | Posted in General Discussion on February 17, 2009 05:20am

my first posting, so thought would try with sonething that seems logical, but flys inthe face of water conservation.  i am in the process of roughing out a basement bathroom and will be installing a Moen shower valve soon.  as i am on my own well, thought i would have at least one shower inthe house that offered a a bit more shower head volume.

it would not take much to enlarge the outlet holes a tad.  currently about 5/16″ ID.  even a 1/16″ increase in ID results in a 44% increase in cross-sectional area.  assuming pressure stays the same, volume is proportional.

thoughts?

 

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Replies

  1. Leegs | Feb 17, 2009 05:27am | #1

    Most likely the flow restriction is not the holes in the showerhead, but rather a single restricted passage in the 'back' of the device, where the water flows into it. 'A friend' told me he that he enlarged this page and got much improved water flow.

    1. brucet9 | Feb 17, 2009 05:43am | #2

      I think the OP was talking about orifices in his shower valve. I doubt that a shower head with 5/16" holes would give a very pleasant shower experience.BruceT

      1. sixfingers | Feb 17, 2009 05:46am | #3

        correct.  I am referrring to the temp balancing valve.

  2. barmil | Feb 17, 2009 05:52am | #4

    Take a one inch supply into the cartridge, and you'll find half inch or 3/8 inch orifices in the cartridge if you're lucky, probably smaller. Same for your kitchen faucet. The hand shower hose is about the same, also maybe smaller. I've always found this to be a contradiction to the advice to have a certain sized pipe feed a bath or kitchen. Maybe a professional plumber can explain it.

  3. ReedB | Feb 17, 2009 06:00am | #5

    Six,  I tried to do the same thing with a Moen kitchen faucet; had had success in the past several times.  But they don't make things the old simple way.  If your shower has any kind of diverter in it to change between tub and shower, watch out.  I had to replace the faucet because the bigger hole messed up the pressure required to activate the spray mechanism (at least that's my theory).  Anyway, what seemed to be a simple way to get more water ended up costing me.  Best of luck.

    1. sixfingers | Feb 17, 2009 06:43am | #6

      good insight.  as this will be a shower only, that will not be a problem.

      but, i just took the valve apart and think i may have ansered my own question.  the cartridge is designed (or so it seems) such that enlarging the inlets may have little if any benefit.  the cartridge in other words is the limiting link inthe chain. 

      i may drill/hone for kicks.  bigger is always better, right?

       

      1. ReedB | Feb 17, 2009 06:50am | #7

        You bet!  I started taking things apart when I was eight or so and haven't stopped for fifty years.  My brain just loves to figure out how things work.  In the last couple of weeks, it's been a Hyundai manual transmission (trying to find a replacement part), a 1940's wood rocking chair (first time learning to hand tie upholstery springs), and a 1971 IBM Selectic II typewriter (back to the customer in working order).  In other words, I have no life.  But it's fun.

        1. sixfingers | Feb 18, 2009 06:50am | #8

          agreed.  i am alot like you.  in the last week, i have torn apart our water cooler looking for a leak, installed an O2 sensor on my car, installed a deep groove alternator pulley on my classic car (it was throwing belts at 6000 rpm), and put a new tweeter in a old speaker.

          1. ReedB | Feb 18, 2009 10:57pm | #12

            Six- isn't it kind of cool not to be afraid to just tear into-carefully of course-into something you've never done before and know that you have a pretty good shance of fixing the problem or making something you need? I feel alot more self-sufficient and it gives me something to do besides watch tv-boring-in the evenings and on bad days.  If I can see it , I can pretty much figure out how it should work and what it takes to fix it. I believe I put you in my friends list.  Take care

  4. skipj | Feb 18, 2009 07:48am | #9

    The flow restrictor is probably not in your valve, it will be in the shower head. I always remove them.

    If I recall correctly, Moen makes it easy. Carefully take the shower head apart, look for a white nylon bushing with a small hole in it, that is your flow restrictor; as long as it's there the valve alterations won't matter. Moen thoughtfully provides a screwdriver slot for you to remove this abomination, right on the restrictor. Select the proper sized flat head driver, unscrew the restrictor, and mail it to your favorite enviro group.

    All shower heads currently sold have some form of restrictor: remove, drill, pry out.

    Have fun!

    1. User avater
      Sphere | Feb 18, 2009 04:01pm | #10

      I once had one that I drilled out, I forget, maybe to 3/8ths or so.

      It was too much, it caused too little pressure ( remember our fluid dynamics?) So the fix happeend to be a penny, with a smaller hole, but bigger than the orig.  Cheap "dial it in" method..seems a penny fit the shower head perfectly.

      And if you ever need to drill pennies , you find drilling from the back is easier, the bit don't skate all over Abe's face, the memorial has slight grooves to keep the bit from wandering. I hold the penny with visegrips. Drill press or hand drill.

      Pennies make great roves for home made big rivets when used with copper slateing nails. I've attached all sorts of tool bags to belts that way. Just peen the nail over and hammer up as tight as you want.Spheramid Enterprises Architectural Woodworks

      Repairs, Remodeling, Restorations

       

      They kill Prophets, for Profits.

       

       

  5. RobWes | Feb 18, 2009 05:01pm | #11

    You want a real shower? Dump the Moan and buy a 3/4" Grohe temp valve. Pipe it into 1, 2, or 3 3/4" volume controls, off these volume controls run shower heads and body sprays not forgetting to build balancing loops. DO NOT FORGET that you will need more hot water storage or making capacity.

    I've done a few. They work great. More detail can be found on their web site.

  6. User avater
    jonblakemore | Feb 18, 2009 11:25pm | #13

    You could just use a Moen 3371 with the 3/4" connections already built in.

    Like the others, I would be afraid that your "enlarging" would cause other problems.

     

    Jon Blakemore

    RappahannockINC.com Fredericksburg, VA

    1. barmil | Feb 19, 2009 05:46am | #14

      Whatever is chosen, recognize the flow restrictor that'll wimp down your shower, no matter what's fed to it. Nonetheless, it's a fact that the passages in modern cartridges and hand showers are much, much smaller that the pipes leading into them, so that makes a difference in what's delivered at the shower head.

    2. sixfingers | Feb 19, 2009 06:33am | #15

      was not aware of the other Moen valve.  I did enlarge, tho only by about 1/16" ID.  based onthe geometry of the cartridge, i felt anythng more would be counter prodcutive.

       

      and it was already installed this afternoon,  I should read my e-mail more often!!!

       

  7. Lansdown | Feb 19, 2009 06:55am | #16

    There usually is some sort of flow restrictor that you can just take out. I have done it on American Standard, Grohe and Moen shower heads in the past. The Grohe had so much pressure, my DW asked me to put it back in though lol.

    1. sixfingers | Feb 20, 2009 02:07am | #17

      i do not think it was as easy as removing a flow restricter, hense the "honing" of the brass housing.  If anything, the cartridge itself is the restrictor.

      1. User avater
        JeffBuck | Feb 20, 2009 02:56am | #18

        did ya try to take out the flow restrictor?

         

        one of the first things I do when going into a hotel room I'll be in for more than a day. I take it out and set it aside. Put it back in before check out.

        I'm all for saving the planet ... just not at the cost of a decent shower.

        Jeff    Buck Construction

         Artistry In Carpentry

             Pittsburgh Pa

        1. RobWes | Feb 20, 2009 04:57am | #20

          Your 100% correct.

          I start my day in the shower and I want my day to start with a great shower. It's even better when the Mrs joins in.

          I see zero fun in doing something half ####.

      2. Lansdown | Feb 20, 2009 03:26am | #19

        In the ones I've removed, it was just that, a small plastic restricter, no honing involved.

        1. sixfingers | Feb 20, 2009 06:25am | #21

          the Moen "Posi-Temp" type valve does not have a plastic restrictor.  i will compare the flow rate of this "modified" valve to an existing shower upstairs soon for kicks.  could be a waste of time, but like already, a good hot shower is great, and better if the water is not dribbling out becuase the Feds said so.

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