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1 faucet in the home has warm water, not hot

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youracman

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First post for me- Have a "never seen this before" question for ya: My daughter bought a model home about 7 years ago so the home is about 12 years old now. Just recently, the faucet in the master bath tub quit delivering "hot" water. The hot side is very warm (maybe 105 degrees or so) but definitely not hot .... never happened before. EVERY other fixture in the home (every sink, shower, etc) yields super hot water. The tub faucet is a Moen wide set with separate handles for hot and cold. I do not believe there is an "anti scald" device anywhere in the plumbing of this home.

The only situation I can visualize that could cause this problem is that there must be some (undesired) interaction between the hot and cold cartridges in the fixture; i.e., when the hot is opened it does something to let a bit of cold water out of the cold cartridge (even though the cold is "off") and it mixes to drop the temperature of the water exiting the faucet nozzle. I don't know how the cartridges are designed or if this is even possible but I can't envision any other explanation. This is the only fixture in the home that doesn't yield hot water when just the hot is turned on. (BTW- The cold side on this fixture works normally.) The tub fixture has worked fine for about 10 years and nobody has "messed with " the plumbing in any way. Ever seen this before? Is my logic plausible?

I'll try to post a pic of the fixture ........... just to show it is very ordinary/nothing special.

Thanks in advance for your thoughts; I am stumped on this one.

Ed Sievers in DenverLJs Tub Faucet.jpg
 

Jeff Handy

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This sounds like a hot and cold crossover.
Often caused by a defective cartridge in a nearby single handle faucet.
But it can be a single handle faucet anywhere in the house.
Also sometimes a defective solenoid valve on a washing machine.
This is what arctic bill was getting at.
Moen brand valves, and others, are guilty of causing this.
Even when shut off, hot and cold can run through them and get mixed, as the water runs to other fixtures.
 

pasadena_commut

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Close the shut off for the hot supply line below that faucet.
Disconnect the hot supply line at the faucet.
Run the line into a bucket.
Open the shut off and fill the bucket (possibly a couple of times to empty the water out of the line.)

Is the water coming out of the wall hot?

If yes, bad cartridge in the faucet.
If no, problem is elsewhere.
 

youracman

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Thanks for the suggestions, guys. It turns out that when the home was moved into, there was no COLD water there at that master bath tub. The builder (large Colorado home- building outfit) quickly fixed the problem under warranty... and it has been fine until now. Daughter said you can still see the area where they had to cut ceiling sheetrock in the garage to gain access (2-story home with the master bedroom and bath upstairs.)

Jeff- There is, in fact, a shower adjacent to the tub and guess what?....it has a single-lever fixture.....a Moen. I may just "throw parts at the problem" based on what you guys have written and change out the cartridge in that shower fixture. It has been in there about 10 years or so and maybe that's long enuff anyway. A new cartridge there would restart the clock so to speak so not money/time wasted.

No access to any local shut off valves there at that tub, pasadena ........ would think codes would require it, but evidently not. I really believe that if the body of that tub fixture ever failed, one would have to make an access hole in the front of that plastic tub and replace it with some sort of white plumber's access plate! There is no plumber's access there now .... not even in the wall......it's all tiled. Cheeeze ....... bad news. As it is, I shut the whole house water off in the basement to work on the plumbing so it makes me real nervous thinking about the outcome if I broke something. Always thinking about how I could cap things off so the rest of the house could have water.

BTW- The first plumbing problem I found (at move in time) was that the hot was on the RIGHT and the cold was on the LEFT in the laundry room! Of course when daughter's appliance guys came and hooked up her washer they didn't know that ......... weird laundry results, of course. I just reversed the connections and made a laminated tag to hang there.........for the next installer. I have since been told that is one downside to buying a model home...........the craft are under insane pressure to get the model homes up so they can get sales going. I don't doubt that.

Thanks again. This is a great forum. I'll post back on progress .......... (or the "fix" .... I hope.)

Be safe.
Ed S. in Denver
 

pasadena_commut

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No access to any local shut off valves there at that tub, pasadena ........ would think codes would require it, but evidently not.
Tubs with shutoff valves are exceedingly rare. However, there should be valves under that sink. If there isn't it would be a good idea, as long as you will have the water off for the shower, to add them. If you don't know how old the sink's hoses are change those at the same time.
 
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