3/4 inch supply line to master bath, but 1/2 inch line at shower valve?

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hj

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As previously stated, the waterway in a 3/4" valve are larger than in a 1/2" one but not by much, and neither has the area of a 1/2" pipe so you would get SOME increase but not a great deal.
 

Barbourdg

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Still little confused. We have a choice of 3/4 or 1/2 lines to use for the thermostatic valve. If we use the 3/4 valve, we can either go with 1/2 or 3/4 volume controls. All of our devices have a 1/2 intake on them.

We were thinking that 3/4 would be good, since we have the option for more output. If we want to conserve water, we simply don't open up the volume controls all the way.

Regardless, we don't plan to use more then 10 gpm in the system.

Thanks and sorry for all the questions. Really appreciate it though!
 
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Jadnashua

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If you're going to use individual shutoffs to the heads, a 1/2" one should be fine.

Make sure that the valve is designed for individual shutoffs, and doesn't want a diverter valve. The difference is, with a divertor, you'd have to turn the main valve off (if it has one) to stop all water. With individual shutoffs after the mixing valve, you wouldn't.. Some thermostatic valves don't like to be 'open' all the time with no flow.
 

Hackneyplumbing

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custom shwr 4.JPG

custom shower 3.JPG
 

Barbourdg

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virtual_shower.jpg

Still tweaking, but here is the basic design I created in Photoshop. Still debating on (4) individual volume control valves or a 3 way valve. In this picture I am using a push button Toto valve on the rain head. They don't come in oil rubbed, so I am stuck with brushed nickel. I originally was going to use an oil rubbed rain head in the ceiling, but it seemed like over kill. The brushed nickel rain head, goes with our recessed lighting and sconces on the other side of the bathroom.
 

Jadnashua

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Go with the 1/2", otherwise you might loose pressure. To compensate you might have to jack up overall pressure to get more pressure through this valve (rather than a 3/4") but then you'll have increased pressure at other points in your system (faucets, other showers, and the like).

Wrong! the size of the supply pipe has nothing to do with the available pressure..it will be the same whether the supply is 1/8" or 2", but a larger pipe can supply LOTS more VOLUME! It's all about the area of the opening. pi*r^2...it's the squared factor. .5" ID, .25^2=0.0625 .75" ID, .375^2=.140624 or 2.25x more volume available (no need to multiply by the constant of pi, which makes the math easier!). You want to be able to supply more volume than the shower heads can use - this is what allows them to use all of the water their internal restrictions allow. When your supply is smaller than the amount you can use, then you'll find the performance lousy.

The only downside of larger supply lines is that there's more water to purge when trying to get hot to the valve. This is where a recirculation system can help or keeping the distance from the heater as short as possible.
 
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