New Bathroom Remodel Tub Spout Leaking - Please Help!

Discussion in 'Shower & Bathtub Forum & Blog' started by StumpedHomeowner1, Mar 5, 2021.

  1. StumpedHomeowner1

    StumpedHomeowner1 New Member

    Mar 5, 2021
    Brand new remodeled bathroom tub shower has leaked since day 1. It is a Moen setup, the new M-Core 140CIS valve with a U361CI transfer valve connected to a rain shower head, hand shower, or both simultaneous as well as a tub spout with diverter. Original parts are from supply house (not HD) and both the valve and the cartridge have been swapped out with new replacement parts sent directly from Moen by a plumber.

    The leak tends to vary. Sometimes it is a consistent and steady single drip and sometimes it comes out more in spurts of water (doesn't leak, spurts some water, doesn't leak, etc.). The last time the plumber was here and replaced the valve, we did not use the bathroom for a day and the tub was dry. Once we started using the bathroom (shower, new toilet, new sink, etc.), it started to consistently leak again. I got fed up and decided I was going to take care of it myself. I shut the water off to the house, pulled the cartridge and checked everything over. All looked good so I put it all back together. Turned the water on and we had no leak and a dry tub again (I was walking around the house like I was the man). A few hours later before bed, my wife flushed the toilet and 30secs later their is water spurting out of the tub spout. I proceeded to flush the toilet over and over and we consistently got a spurt of water about 30secs after the toilet tank stopped filling. As of now, the leak is more consistent. I can turn the handle to all hot, a mixture, or all cold and it continues to drip.

    Anyone have any clue what is going on here? I think either a water hammer issue or something to do uneven pressure in the home affecting the pressure balancing puck? I do not have a water pressure regulator near the meter in my home. I noticed water hammer arrestors under my kitchen sink and behind my washer and dryer but i do not have water arresters anywhere in the new bathroom. Also, the old shower did give off a slight pulsating water stream when the mixer was at a certain temperature. The new toilet (Toto Promenade) fills fast. However, the toilet nor valve instructions specifically call for an arrestor. I haven't purchased a pressure tester....yet.

    My plumber is adamant that it can not be a pressure issue, but he is the same guy that hasn't diagnosed or fixed the issue in 4 separate trips to the house. He's proceeded to bad mouth Moen and tell me to rip it out and buy a new brand which doesn't seem like it should be necessary. I consider myself a fairly intelligent person and it certainly sounds like a pressure issue to me (maybe the plumber is just trying to cover his own arse).

    Sorry for the novel but wanted to give as much detail as possible. This has gone on for too long and I can't take hearing it from the wife. Please help?!?!?!?
  2. Reach4

    Reach4 Well-Known Member

    Sep 25, 2013
    I am not saying that it is a pressure issue, but having the tub spout drip only after flushing the toilet is strange.

    Buy or borrow a garden hose thread pressure gauge. Under $20, and often a lot under. You can attach it outside, to a laundry tap, or to the drain valve on the water heater. Note the pressure when the tub is dripping and when it is not.

    It is fairly common for residual water to drip out of a diverter spout after a shower. But your description seems to say that these drips are not following a shower.
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  4. StumpedHomeowner1

    StumpedHomeowner1 New Member

    Mar 5, 2021
    It will be dripping and the tub will be wet 24hrs after the last shower. It is definitely more than the typical dripping from the shower head draining after a shower. To confirm that leak was from the water supply I turned the water off to the house and watched the leak stop.

    It doesn't only leak when the toilet is flushed. But the toilet being flushed does seem to create an increase in water (a spurt). Also, flushing the toilet seemed to start the leak back up after the plumber had put in a new cartridge which temporarily stopped the leaking for a short period.
  5. Tuttles Revenge

    Tuttles Revenge In the Trades

    Oct 15, 2014
    2nd Reach4's advice.. And if its not a water pressure issue, and the cartridges have been replaced and it still does it.. maybe the brass valve was damaged.. But rule out water pressure. My warranty is voided by excessive pressure that a customer declines being addressed at time of installation.
  6. StumpedHomeowner1

    StumpedHomeowner1 New Member

    Mar 5, 2021
    Cartridge was changed once. Brass valve was changed once. Static pressure is ~73psi but the new Toto toilet was causing a spike in pressure when flushed at ~155psi. Had a plumber suggest water hammer arrestors at the shower valve, which have been installed but have not stopped the issue. Sometimes it’s a consistent drip, sometimes it’s more of a spurt of water that stops for a while.

    1) Is 73psi too high of a static pressure that it could be causing a leak at the valve?
    2) Could the hammer from the toilet have shifted or damaged the cartridge? Meaning do I need to replace the cartridge again since the arrestors were installed?
    3) Could it be something to do with the pressure balancing valve? A difference between the hot and cold pressures?

    I do not have a pressure reducing valve after the meter or a thermal expansion tank, which is something that might not be a bad idea regardless. Just not sure that would fix this specific issue.

    This is driving everyone involved nuts so I appreciate all the help/suggestions/ideas. This forum has been well read over the past few weeks by my entire household!
  7. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Sep 2, 2004
    Retired Systems engineer for defense industry.
    New England
    You said you had a pressure reduction valve. Do you also have an expansion tank? If you do, check that it’s not full of water from a damaged bladder. Expansion from heating water can easily raise the pressure in the home until you open a valve, or something leaks. A working expansion tank is what prevents that from happening.

    Any fast acting valve can cause a spike, and a water hammer device can help. Don’t blame a toilet for actually shutting the water off reliably. Toilet valves are often the weakest link that allows expanding water to escape without it causing the safety valve on the water heater from opening. When all of the valves are good, the weakest link is where the leak occurs. No valve is designed for above the 80-psi dictated as the max in a residential location...if you’re seeing over that, solving that should solve your leak in the tub.
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