Mixing valve for shower and separate valve for bathtub

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charlesp210

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I'm getting new alcove bathtub shower and tile replacement soon. Current plan is single mixing valve (Delta 1700 series) with diverter spout to redirect water into the shower. Diverter spout is what I've used all my life.

But now it occurs to me that it makes little sense to use the same mixing valve for both the bathtub and the shower. For one thing, it would be much nicer to have the shower mixing valve at about 3 foot height, to adjust while I'm taking a shower. Meanwhile, it would be nicer to have the bathtub mixing valve closer to the bathtub height, maybe 20 inches or so, like the current one I'm replacing. When I'm taking a bath (which I haven't done in awhile) I can control the Moen-style single handle valve I have now with my feet, for example, tapping it closed when I've had enough extra hot water. I won't be able to do that if I move the mixing valve up to 3 feet high. If I want to make adjustments I'll have to get up out of the bath and make them standing up.

I'm not even sure what to call this dual valve arrangement. When I search for "dual valve shower" what I usually get is his/hers on opposite sides of shower.

Other advantages are that I wouldn't have to mess with my shower temperature setting if I want to fill the bath with hotter water. I just keep each valve set to the appropriate temperature.

Has anyone thought about this arrangement?
 

JohnfrWhipple

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I have not. My first thought was - maybe you can get more bendy. Do some stretches and not worry over the 10 inches.

If that is not an option could you not install a thermostatic control valve and a couple of flow valves?

JW
 

hj

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quote; as anyone thought about this arrangement?

Go to apartments or hotels, such as those in Chicago or New Your), which were constructed in the 40s, and maybe earlier, or the Queen Mary, and you will find MANY like that. At one time most of the major brand valves, such as American Standard, had "pass through" openings on the top so you could screw in couple of nipples and install the shower valve above the tub faucet.
 
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charlesp210

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For one thing, it would be much nicer to have the shower mixing valve at about 3 foot height, to adjust while I'm taking a shower. Meanwhile, it would be nicer to have the bathtub mixing valve closer to the bathtub height, maybe 20 inches or so, like the current one I'm replacing. When I'm taking a bath (which I haven't done in awhile) I can control the Moen-style single handle valve I have now with my feet, for example, tapping it closed when I've had enough extra hot water.

Forget the feet part…I got in the tub again and that doesn't work well anyway, I might have done it once when I couldn't otherwise move, and it probably isn't a good idea--could damage something. But back to OP I am really liking separate valves for tub and shower and hoping I can get the plumber to do it. Especially with a valve like Delta 1700, my plumber's favorite, it can't be too low when you're taking a shower because you have to reach underneath the center of control to control the all important volume, so mounting it below 48 inches on center is lousy when your taking a shower, but obviously makes the valve unreachable if you're taking a bath.

AND, I think a Moentrol single handle V/T control (it appears no one else makes a control like this anymore) makes the best sense for a tub. My plumber seems not to like this valve and strongly prefer Delta. But let me explain why the Moentrol is perfect for bathtub. During one bathing session, you may need to adjust the volume and temperature in many different ways. You start out full force hot or nearly so. Then if you overshoot, you run colder water for awhile at some intermediate volume. Then you run a trickle hot during the bath itself. If it gets too hot you may need another blast of medium cold, and so on. A single handle valve is perfect for making all these changes on the fly, even if it doesn't allow finer control of pressure, and the "memory" aspect of temperature control isn't that great.

OTOH, the 1700 with dual handles is perfect for a shower. For a shower, and for especially for one person, you basically can set the temperature control once and forget it. Just turn on and off and up and down the volume as needed with the larger volume handle.

So this gives another reason for having dual valves. The temperature dynamics are completely different. For shower you just want constant temperature, for bath you need to vary the temperature all over the place. And if you take a bath, you need to remember to re-set the temperature next time you take a shower. And it might be good to have different kinds of controls as well, with dual handle control for shower and single handle for bath, as I have just described.

Finally, there's a third good reason for separate mixing valves. No surprises. This is especially true with spout type diverter. I can't count the number of times I've pulled the spout diverter and it doesn't go as expected--wrong spray head selected, wrong spray option, too much pressure, etc. If you have a fixed control (or another kind of diverter) you don't get those kinds of surprises. You just ramp up the volume from zero. But even with an in-wall diverter, you can still have the surprises coming from forgetting to check which way the diverter is turned.
 

hj

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The Moen "Moentrol" valve DOES adjust the volume and temperature separately, but with a single knob. A "spout type" diverter does NOT give you "surprises" it either flows into the tub or up through the shower depending on whether it is up or down, (or "in or out" for that matter).
 

charlesp210

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The Moen "Moentrol" valve DOES adjust the volume and temperature separately, but with a single knob. A "spout type" diverter does NOT give you "surprises" it either flows into the tub or up through the shower depending on whether it is up or down, (or "in or out" for that matter).

My meaning was that you grab the control once and then you can control both temperature and volume with one hand, which is convenient when you are not to fussy about setting the exact volume and temperature (as with tub, already filled with water, has a lot of thermal inertia, so you don't have to be exact in setting temperature of incoming water). Separate controls for volume and temperature give more precision to both, but require two separate operations (or two hands, but usually two separate operations with one hand first reaching one control, and then the other). Or maybe more than two separate operations.

The surprises in using a spout type diverter come from the fact that you can't start from zero flow. The water must already be flowing, then you can pull the diverter to go to shower. (At least all the spout diverters I've ever used were like that…and some required very substantial flow before they would divert.) Then, unless you have made sure the correct spray function is enabled, you can be surprised at what happens when the flow hits the spray head. This has happened to me countless times. I may get blasted with the wrong spray, or have the spray head pointed the wrong way. I can get blasted with cold standing water from the pipe, or hot water I intended to point down when someone last turned the head up. Also, with spout diverter, I'm first looking down and testing the water coming out of the spout rather than looking up at the spray heads to see what's going to happen (which would be starting from the tiniest trickle there if there were no diverter).

The surprises with an in-wall diverter come from not noticing which way the diverter is pointed when you start the shower (or bath). I may have been expecting bath, but the last person took shower, then wham.

My plumber is now estimating the dual control cost, which I'm pretty sure is what I will buy since I believe it's a great idea and especially because I rediscovered it. But he didn't betray noticing my hints about how a single knob v/t might be better for bath, and I didn't want to argue with a great plumber who happens to know and like Delta valves best, so it looks like I will get two Delta 1700 valves, which is not a bad solution either.
 

hj

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quote; My meaning was that you grab the control once and then you can control both temperature and volume with one hand, whic

I KNEW what you meant, and that is what the Moentrol DOES. Most people, if they are using multiple devices do NOT use a diverter spout to make the initial flow change, (in fact, some manufacturers specify NOT to use the bottom outlet for a tub spout). They run the water TO the diverter first and use that to control flow to the spout or various heads.
 
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