Moentrol Valve - weird issues

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by mikekenmore, Sep 26, 2020.

  1. mikekenmore

    mikekenmore Member

    Joined:
    Aug 13, 2015
    Location:
    Kenmore, Washington
    i recently removed tile and installed new backerboard and tiles in a shower/tub unit. the plumbing pipes were not connected to anything and they moved in and out relative to the tile wall. the old valve is an old school moentrol. i didn't add blocking to the valve since i didn't know the correct depth and figured that if it worked in the past like it had been, i should be good to go in the future. this is in an old condo building that we rent out.

    now, after installing new trim set, i found that i could not install the screw all the way into the threaded hole of the valve; when i did this, it would turn on the water (presumably because the whole system wasn't secured in the wall). so, i set the screw loose so that i could pull the water on and depress it so that it shuts off completely. it seemed to work at first, but when i went back today (i'm selling the unit, hence the remodel), i found that in filling up the tub, there would be a little trickle of water from the shower head if i pulled the handle all the way out. the trickle would take 5 or so seconds to form, but then would be continuous.

    the way to remedy the trickle was to push the screw in a little bit so the water wasn't full pressure, but that's obviously not a long-term solution, especially if/when the inspector comes to look at this.

    what am i missing? what am i doing wrong? and how can i fix? i can make access to the wall if needed, but it's really a last resort since i would have to cut in from the hallway.

    one thought i had, which is totally not a good idea, was to apply some goop (glue) to the screw and handle so that the screw was no longer loose within the handle. i think there's about 1/4" gap on the screw head to the handle when turned off, so i can't really turn off the water without pushing on the screw itself.

     
  2. mikekenmore

    mikekenmore Member

    Joined:
    Aug 13, 2015
    Location:
    Kenmore, Washington
    IMG_0341.JPG IMG_0342.JPG

    [​IMG]
     
    Last edited by a moderator: Sep 28, 2020
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  4. Terry

    Terry Administrator Staff Member

    Joined:
    Aug 17, 2004
    Occupation:
    Plumber
    Location:
    Bothell, Washington
    They make a handle extension for the Moen.

    https://www.moen.com/products/Moen/Moen_Handle_extension_kit/137347WR

    [​IMG]

    That valve that you have as a diverter built in for the shower head, and I see that you added a tub spout with diverter. The tub spout gets run in copper or fill sized pipe or it will push water up to the shower head.
    Anything smaller like PEX or CPVC will push the water upward.

    [​IMG]
     
    Last edited: Sep 27, 2020
  5. mikekenmore

    mikekenmore Member

    Joined:
    Aug 13, 2015
    Location:
    Kenmore, Washington
    thanks for the info Terry.

    how does the extension piece solve the issue of not being able to fully shut off the water? seems like by sticking out more, it would just cause the screw to pull more on the valve???

    yes, i replumbed the spout portion of the line with a sharkbite elbow. methinks this is the restriction, unfortunately. i see moen has a shower pressure control valve, but that seems really hokey to me.
     
  6. Terry

    Terry Administrator Staff Member

    Joined:
    Aug 17, 2004
    Occupation:
    Plumber
    Location:
    Bothell, Washington
    [​IMG]

    The instructions mention not reducing the pipe size to the tub spout.

    It has been plumbing code for decades now with the requirement to either pressure balance or thermostatically control temperature. It's really a great idea. I had three valves like the one you had at my mothers and I replaced all of them with the Moen pressure balanced faucets.

    Is this the valve you have?

    [​IMG]

    If the old trim looked like the one below, I often need the extension kit for it to work with the more recent trim that isn't concave. Otherwise the handle hits the plate before it shuts off.

    [​IMG]
     
    Last edited: Sep 27, 2020
  7. mikekenmore

    mikekenmore Member

    Joined:
    Aug 13, 2015
    Location:
    Kenmore, Washington
    yes, that's the valve i have.

    question: do you have availability in the next week to do a service call? project is in lower queen anne.

    i don't think i reduced the pipe size necessarily, but perhaps the sharkbite reduces flow just enough to make the difference. i tried today without the diverter on and it still dribbled water out the shower head. here's what i used: https://www.homedepot.com/p/SharkBi...gree-Stub-Out-Elbow-Fitting-U351LFA/202721918
     
  8. Helper Dave

    Helper Dave In the Trades

    Joined:
    May 25, 2020
    Location:
    Wisconsin
    Did you leave the little plastic sleeve in the sharkbite? Those for certain restrict flow too much for the tub spout.

    They're supposed to be removed for copper pipe, and I've seen other shower valve set-ups using sharkbites successfully, so I presume it's just the sleeve that causes the problem.

    Other plumbers chime in if you've seen them cause problems more consistently.
     
  9. mikekenmore

    mikekenmore Member

    Joined:
    Aug 13, 2015
    Location:
    Kenmore, Washington
    no, i didn't take out the plastic sleeves. dang!
     
  10. mikekenmore

    mikekenmore Member

    Joined:
    Aug 13, 2015
    Location:
    Kenmore, Washington
    helper dave: thanks for the idea on the sharkbite plastic. i cut a hole in the backside of the wall and removed it. no more drips

    terry: thanks for the product recommendation. i ended up not using the sleeve, but did use the brass extension. i was nervous, b/c the long screw bolt they provided was just long enough, but it seems to work fine now.

    project complete. time to sell!
     
  11. hj

    hj Moderator & Master Plumber Staff Member

    Joined:
    Aug 31, 2004
    Occupation:
    Plumber
    Location:
    Cave Creek, Arizona
    The handle was too close to the plate. When you tightened the screw, it pulled the stem out turning the water on.
     
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