View Full Version : Pressure-balancing Moen shower-tub valve releasing hot water in the "cold" position

10-01-2010, 12:30 PM
The 16 year-old building of 45 one-bedroom apartments I live in has just had a complete repiping: all old copper pipes replaced with PEX ones, old shower valves replaced with new Moen ones (1085 aka 8370), sink faucets replaced, etc. After the work on my bathroom was done, I noticed that the water coming out of the bathtub faucet upon opening was not cold -- as one would expect, when sliding the lever counterclockwise from its closed position at the bottom -- but hot, and grew cooler as one moved it counterclockwise to the 3 o'clock position on the right. From that maximum coolness (note, just "cool," not cold!) at 3 o'clock, the water then became warmer again until it reached maximum warmth at the 9 o'clock position on the left (the water here does seem to attain the expected fully "hot" temperature).

When I became aware of the issue, I mentioned it to the plumbing team leader, and he acted as though it was the first he had heard of the problem (though he has been extremely circumspect and terse in his communications with residents since his *second* week on the job) and would look into it. I then approached the plumbers who were at work in the hallway outside my suite, and one of them came in and felt the water, and, in all sincerity, informed me that all the suites were like this, and that it was due to what he called a "gap" (English was not his first language, so I'm not exactly sure what he was trying to say) at the back of the valve assembly that allowed a crossover or mixing of the hot water with the cold.

I then called Moen's customer service line, and described the situation and the plumber's comment, and the young woman said she had not heard of such an issue on a freshly-installed valve in her years of working there, and the fact that it was affecting all suites would suggest that it is a water pressure issue. She told me that this is a pressure-balancing shower-tub valve and requires equal pressure from both the hot and cold water, and that problems will arise if it is not. She advised that the water pressure should be tested to confirm that it is equal for both the hot and cold water.

I then spoke with the project manager for the plumbing work, and after he felt the water coming out of the faucet over the tub, told me in a dismissive and condesccending tone that if *that* was the worst thing I had to worry about, I was doing pretty good. He then walked out. (I didn't have even have a chance to tell him that his communication skills were being wasted in the plumbing business, and that he should consider a career in politics!)

I might also mention that the water in the kitchen is no longer as cold as it used to be (even after letting it run for 20 or more minutes), and I suspect that hot water may be mixing with the cold there as well, though the water there does at least get "cold" and not just "cool" as in the shower.

So, anyone have any kind of clear idea what is causing this problem and how it can be fixed? Should the plumbing company be paid in full for work with this outcome (and this is a job costing, for the two sister buildings involved, well into the seven-figure range), or be required to make whatever changes necessary to guarantee that, in all suites, only cold water water flows out of the tap when the faucet is in the "opening faucet" cold position? Was the project manager's attitude and behavior acceptable for a professional who can and must be held accountable for the work performed under his supervision?

Many thanks for your comments and responses!

10-01-2010, 05:26 PM
They need to take the handle off turn the stem 180 degrees and reinstall the handle.

10-01-2010, 06:17 PM
Unless it is a Moentrol, the cartridge has to be removed and rotated 180 degrees, IF that is the problem, which the action as described does not indicate, since maximum hot would be to the right and maximum "cold" to the left, not hot-cool-hot. There is no "gap" in the valve, and only defective ones allow the water to cross over.

10-01-2010, 06:20 PM
If it's a Posi-Temp, you may have to 180 the cartridge.

I wouldn't worry too much about the plumbers there being customer service reps.
On a big job like that, you may find workers that like installing, but may not be good with people. Then you have some workers that don't like getting their hands nicked up and bleeding, but love talking to people. You have several types of personalities, and with a big job you may have them all. I work with all types in construction, and the trick is to place everyone where they work out the best. Remember, the job they have been asked to do isn't the easiest thing to do, but they may be very good at that job, or at least can get the job done. You may need to give them a punch list for the small items they overlooked, or just haven't discovered yet.
In many repipes, they may run the hot or cold to the wrong side to a single handle faucet, knowing that they can spin the stem later.
There is a certain kind of logic to it. Depending in your valve, it may be fixed by spinning the stem 180, or it may require rotating the cartridge 180. Either way, it will have to be done.

I could tell you some funny stories of "Rough" plumbers. Sometimes while talking to you, they may "park" their claw hammer in the framed wall, and then pull it out of the wood stud when they move on. Some like to use a hammer to pound out drywall if they are removing a section rather then using a jab saw. Drop cloths, some act like they've never seen them.

Trim plumbers are much better inside after the flooring has gone in and are normally much better with people. But.........you may not be able to make him use a pick or shovel either. Too dirty.

Think about your workplace. Does everyone mop floors, vacuum and take out trash? Does everyone do accounting? Or sales?
Most people have narrowly defined job descriptions, and yet, somehow it all works.

10-04-2010, 11:17 PM
Thank you for the responses!

Yes, it is a Posi-Temp (does that by itself indicate whether it is the stem or the cartridge that should be given a 180?). I have already informed one of the plumbers of the advice dispensed here, and hopefully the remedial action taken will prove successful and the matter will be happily resolved with little fuss.

Thanks for taking the trouble to write that explanation of things from a plumber's POV, Terry. I am certainly aware that it's a big job and that little things can be forgotten about or overlooked. The conduct of the actual plumbing crew has been nothing less than exemplary throughout. In fact, they were awarded the contract partly on the basis of their understanding that "people skills" would be as important on this job as plumbing skills. How ironic that the dude who conveyed this information to me is the very one who went on to insinuate that my expectation that hot water should not flow out of the cold side of the faucet is somehow outrageous. (Part of the health regimen I follow includes ending showers with fully COLD water; merely "cool" water is NOT the same, and as things stand––or, rather, flow––a cold shower is an impossiblity.)

No, the odd conduct has been on the part of those overseeing the work and the project: how can they be aware that hot water is flowing out of the cold water side of the tub faucet in 45 suites and simply carry on as if nothing is wrong? Everyone to whom I have described the situation here (including several Moen wholesale salespeople) has said it is not normal and that there is a problem somewhere (and it's not likely to be 40-odd new Moen shower valves...). I would expect an honest professional to admit the same and to offer (without any arm-twisting) to complete the job to the end user's satisfaction. That this has not been the case is not only puzzling but, indeed, mightily disconcerting (what other less immediately-noticeable problems await discovery weeks, months, or years down the road?)