Moen shower faucet replacement - one hole? - get a constant temp?

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haeffnkr

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Hi,
I have a standard Moen mixer shower valve. In the winter it is hard to keep the right mix of water to keep a constant temp out of the shower head. Yes I could replace the cartridge again and maybe see marginal improvements. Wife is tired of always adjusting it back and forth in the shower.

What I am looking for is a 2 handle shower faucet that fits into the one big hole so I don't have to redo the whole shower wall? Are there any faucets like this for me to purchase?

I assume it would give me a more constant temp since I would keep the hot full on and only be adjusting the cold side?

thanks in advance
haeffnkr
 

Mr tee

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You will need to open up the wall a bit, but there are repair plates with two holes made to cover the larger opening.
 

haeffnkr

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Two handle faucets haven't been code approved for decades now.
Do you have a tankless water heater?

Oh? I have a 2 handle on my tub. Both were installed when the house was built 20 years ago.

Yes I have a tankless water heater on the far side of house from this shower. That fluctuates a bit in this shower. That my wife and I struggle with.
 

Terry

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Oh? I have a 2 handle on my tub. Both were installed when the house was built 20 years ago.

A tankless water heater heats the water as needed based on flow. Alter the flow and the amount of fire changes too. If the handle is moved often, the tankless makes and adjustment for the different flow. The more tweaking, the more changes.
A tank will have more of a uniform heat that it can dispense.

When looking at pressure balancing and thermostatic "shower" valves, those are code.
A tub only without a shower doesn't need pressure balancing, though it does need to be limited to 120 degrees or less and are sometimes equipped with a tempering valve, sometimes in the lav cabinet nearby.

delta_bt2710_8.jpg
 

haeffnkr

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A tankless water heater heats the water as needed based on flow. Alter the flow and the amount of fire changes too. If the handle is moved often, the tankless makes and adjustment for the different flow. The more tweaking, the more changes.
A tank will have more of a uniform heat that it can dispense.

I get that.
It is amplified in the winter since the water is hotter and colder. In the summer mixing 120 degree water with 78 degree cold water is easier to control than 132 and 50 degree water in the winter.

Thus .... I want a 2 handle full on hot and adjust with cold only in the shower. The hot will not ever change flow or temp and I just adjust with cold, should be much more stable.
Is my logic wrong?

thanks haeffnkr
 

Terry

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jadnashua

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I think you may be better served by a thermostatically controlled shower valve. Both what you have and are proposing are essentially simple mixing valves, but as the incoming water temperature changes, all it does is retain the same balance...it does nothing to keep the actual temperature the same as the inlet temperature changes. A thermostatically controlled valve tries to maintain the outlet temperature, regardless of what's coming in. Now, some respond quicker than others, but they'll sense the changes probably as fast or faster than the user would.
 

haeffnkr

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Typically a shower head is flow restricted. You might ask how others are doing with thermostatic valves and how they have been working with tankless. I don't have thermostatic, but there are a few here that do have them.

https://www.deltafaucet.com/design-innovation/innovations/shower/tempassure-valve--monitor-valve

View attachment 79949

Only available for dual-function tub and shower faucets

Thanks for think.
I see that the valve can be installed into dual output or shower only rough in bodies.

r10000-un.jpg


https://www.deltafaucet.com/bathroom/product/T17T438.html

Assuming these faucets work, the reviews are positive for the most part, why would this be any better than a 2 handle setup and mix the cold manually?
 

jadnashua

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The R10000 is a rough-in valve that can utilize three different types of valve/trim (big box stores tend to package those two together in a kit, but plumbing supply stores sell them as two parts of a whole so they don't have to stock so many combinations):
- single handle pressure balanced valve
- two handle (concentric) volume, mix
- two handle (concentric) volume, aquastat (thermostat for water)

I put a discussion in the tutorial section you can read more about this if you want.

Anything but the third one, and you'd still be chasing the temperature you want. I don't know how well the Delta thermostatically controlled valve responds to something like a tankless output...I'd call their tech support line. In theory, it should work.

T17T097-PN-B1.jpg
 
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haeffnkr

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JAD~Thanks for the update. Are you saying the Delta thermocontrolled faucet won't work in the linked rough in body? Amazon says it will.

What about a simple 2 handle faucet in a shower? Won't that be the simplest best option?
 
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