Moen Posi-Temp problem - not what you think

Discussion in 'Shower & Bathtub Forum & Blog' started by Alan_E, Nov 19, 2013.

  1. Alan_E

    Alan_E New Member

    Nov 19, 2013
    OK -

    This has me stumped! Our house is 5 years old. The plumbing is PEX with manifolds. My wife started complaining that her shower seemed to be slowing down - not just the hot or the cold, but both. I checked the shower head itself and the nozzles are clear.

    I called Moen and they said the balancing valve inside the 1222B cartridge is stuck, and they sent me out a new one. I followed the instructions to the letter and it was worse than the original!

    So, back to Moen. This time they tell me, "Oh! You have to clean whatever debris is in the valve body out" - and sent me procedures to do that along with a new 1222B.

    I did all they said to do, flushing the valve body so much, I had water coming down thru to the basement from the holes in the flooring where the PEX comes thru.

    The new cartridge is just as bad as the others.

    Now that I am thinking about it, if it is the balancing valve, I should be getting better flow from either the hot or the cold, not low flow from both. The flow is so low, all of the shower head nozzles are not spraying water.

    I am at a loss. Where do I go from here?
  2. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Sep 2, 2004
    Retired Systems engineer for defense industry.
    New England
    A pressure balance valve can actually shut both the hot and the cold off if it senses the pressure difference between sides. It's only goal is to prevent a hot spike, and it does that by trying to keep the balance between hot and cold the same. If the hot supply pressure drops, it drops the cold in proportion, so the outlet temp remains relatively constant.

    Some designs have inlet filters...those could be partially clogged.
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  4. Alan_E

    Alan_E New Member

    Nov 19, 2013
  5. Alan_E

    Alan_E New Member

    Nov 19, 2013
    Are you kidding me?!!!

    I was looking through Youtube to see if someone else had similar problems. I found this:

    I had checked the individual nozzles on the shower head, but I never did pull the head off and look to see if there was any obstruction in the inlet to the head! I cleaned it out and now I have pressure!

    I guess I now have a couple used 1222B's for sale!

    Last edited by a moderator: Nov 20, 2013
  6. Terry

    Terry Administrator Staff Member

    Aug 17, 2004
    Bothell, Washington
    On any faucet or showerhead with low flow, the first place to check is the flow restrictor or aerator.
    They sometimes get clogged.

    I don't normally have issues with the Posi-Temp cartridge.
    Some interesting flukes have been, foam insulation in the pipe leading to the valve one time. I think the previous plumber had used the pipe to punch through foam insulation and then soldered the pipe in place.
    One other time, I found a round plastic ball from the water heater had found it's way to the valve body. On that one, I had to cut the wall and remove the floating ball in the pipe.

    I'm glad you were able to simply clean the screen at the shower head. It's nice when it's that easy. :)


    This one was a tough fix. I had parts of the water heater dip tub in the pipes.
    Last edited: Nov 25, 2013
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