Plumbing question 201

[Richard]

We're starting to finish the basement & adding in a full bath. Wife wants the shower to have 1 overhead, 2 or 4 side "body sprays" and we'll have yet another hand held so someone can sit if need be (we have a neice in a wheelchair)

With all this water spraying I need a 3/4 pipe. No problem on that front, I'm replacing the parts for that soon, perhaps today

The wife said the lady at the store said I needed TWO 3/4 pipes for the various items.

Seems to me I have a single 3/4 pipe coming out of the water tank & my cold tank as well. Given that, it seems no matter HOW many lines I run, I'll still have that as my primary restriction.

If I put a "Y" adapter on them somewhere, I don't see how I gain anything. I might get more flow but I'll get less pressure (my pressure is set based on VAGUE memory, about 40psi?)

If a Y adapter is indeed ok, is it better to put the Y in by the water heater, or could I plumb a single 3/4 line to the shower stall area and then split it as needed?

Seems if I do the latter, I'll have a single feed of hot water if/when the other sprayers are brought into play, rather than a 30' run of stored COLD water in the seperate (hot) line /forums/images/graemlins/crazy.gif for the second set, until the cold water is replaced by hot.

Any thoughts?

/forums/images/graemlins/smile.gif

 

[boustany]

Unless that is a real, real long run, I doubt you'd need any more than 1/2", let alone two 3/4 inch pipe.

Rule of thumb, volume doubles as you move up with each pipe size. The effect of turbulence becomes less and less which adds to the flow potential.

Now, if you look at shower sprays, etc., most all are restricted to about 1/4", and you get a lot of water out of them. (in a lot of places the restriction is code to save water). A 1/4" outlet has 1/4 the flow of a 1/2" outlet (1/2 squared divided by 1/4 squared). I would guess the impact of turbulance, it means 5 or 6 times net. It the fixters are fed with a 1/2" cold and 1/2" hot, thats a lot of capacity.

One thing you should think of is the fact a 3/4 pipe holds a lot of water, which means a lot of cold water has to come out of the hot water pipe before the hot water comes out.

I plumbed my house with a 3/4 inch 'backbone' which spilts to twin manifolds with 1/2 hot and cold pipes, each controlled by ball valves. We have a sort of body spray in our shower, except I have 2 separate controls: one for the main shower head, and one for the other.

 

[Junkman]

For that amount of volume of water you are going to need more than the one 3/4" line to feed it. I assume that you are on a well, and don't have that much storage to keep the lines fully charged when in use. I believe that you will need to bring two 3/4" lines directly to each valve and you might even need to revamp the plumbing from the tank also. I just saw a well pump system on This Old House that has an electronic control that increases the pump speed to keep up with demand without any noticeable difference in pressure or volume. They said that it cost about $200 more than a conventional pump system. Sounds like this is exactly what you are going to need. The shower is going to be the least expensive part of this project.

 

[Richard]

I probably should have clarified that the overhead/sides and handheld will be independent of each other. We might not want a flood in there when the niece is here. The handheld will probably never get used, only the overhead and sides.

The run from the hot water tank to the new shower will probably be 30’ after all the bends are considered. It’s currently ½” most of the way. I currently have open ceilings and full access to swap/add pipes (and just bought ten 10’ x ¾” sticks)

In a manner of speaking, I’m not terribly concerned about water savers. I don’t mean we are not concerned, but I have a 103 gpm well BUT sadly, only a 10gpm pump installed so I’m already “wasting” 90 gpm when I’m at full use.

None the less (directed to Junkman), are you suggesting I might need two ¾ OUTLETS from my hot water tank and my pressure tank (for cold) and run two sets of ¾ pipes to the shower area? (I’ve never knowingly seen a water tank with dual outlets)

I told the wife that no matter how many runs I take to shower, we’re still confined by the single ¾ outlet on the tanks which brought up my wondering about just splitting it AT the shower (single run from both tanks to shower area, then splitting at shower area to separate valve systems)

We’re also contemplating a tankless heater for this shower

 

[bgott]

http://www.chilipepperapp.com/

This ought to deal with the 30' of cold water stored in the lines. I think you would also be able to skip the tankless hot water heater.