Welcome! Here are the website rules, as well as some tips for using this forum.
Need to contact us? Visit https://heatinghelp.com/contact-us/.
Click here to Find a Contractor in your area.
If our community has helped you, please consider making a contribution to support this website. Thanks!

Moen Positemp Shower Valve Issue

Options
kameda
kameda Member Posts: 2
in Plumbing

Recently replaced a faulty PRV valve and set the pressure to the house at 70 psi. Before the change my master shower had lower operating flow than the same valve in my main house shower. The master shower flow did improve but now I am noticing what I can best describe as intermittent trapped air coming through the valve. When I hear this I can also see a slight pulsation of the water coming out of the shower head. My wife's complaint is that the flow rate is not the same as it was when we initially moved in. We are the original owners having moved in in late 2019. Any ideas for diagnosing and fixing this issue are appreciated. Happy wife means Happy husband.

Comments

  • hot_rod
    hot_rod Member Posts: 27,761

    If work was done on the piping, you could have flushed debris into the shower head?

    Remove it and soak in vinegar to clean dirt and calcium scale. As a first step.

    Or debris into the Moen cartridge, simple enough to swap that out. Depending on the model, I believe that is a pressure balance valve and cartridge.

    70 psi is fairly high, PRVs ship pre-set a 45- 50 psi typically.

    Do you have a thermal expansion tank at the water heater. Many of the PRVs act as check valves also, the non bypass models.

    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • kameda
    kameda Member Posts: 2

    Yes I do have a thermal expansion tank on the hot water tank. As for the valve cartridge, it is a 1222 model. I am almost positive there is no debris in the shower head. No way to know about the cartridge without removing it.

  • Alan (California Radiant) Forbes
    Alan (California Radiant) Forbes Member Posts: 4,789
    edited 3:47PM

    I would replace the cartridge and while the cartridge is removed, turn on the water to flush out any debris in the hot and cold lines.


    Have someone at the house valve turn on the water for 5-10 seconds and a second person at the valve with a 5-gallon bucket and see if you get any debris at the bottom of the bucket.

    Add some good quality silicone grease to the o-rings on the cartridge and also inside the valve before you push it in. Moen used to include a little packet of lubricant with their replacement cartridges.

    image.png
    8.33 lbs./gal. x 60 min./hr. x 20°ΔT = 10,000 BTU's/hour

    Two btu per sq ft for degree difference for a slab
    Larry Weingarten

Categories