why copper required for valve to tub spout

[RustyShackleford]

In the installation guide for a Delta rough-in valve:

http://s1.img-b.com/build.com/mediabase/specifications/delta/661078/50353revd_ec5d.pdf

... it states that:

"Pipe (3) between valve body and tub spout must be a minimum of 1/2" (13 mm) copper pipe or 1/2" (13 mm) iron pipe in a straight drop no less than 8" (203 mm) but no more than 18" (457 mm) long with only one iron pipe or copper 90 degree elbow to the tub spout nipple. Do not use PEX tubing for tub spout drop."

Anyone know why such strict requirements, especially the requirement that copper be used ? Obviously it's a bad thing when plumbing that's buried in a wall fails, so maybe they just think copper is less likely to ? Debatable, but that's another discussion I guess. And bathtub plumbing it's likely to be a bigger problem - if it's buried behind tile or a fiberglass one-piece, as opposed to just drywall (though there's often drywall access to the backside of a bathtub).

 

[JJMN]

The tub spout can be copper, brass, or galvanized pipe. You cannot use pex because the pipe coming out of the valve needs to be able to support the weight of the tub spout and handle the abuse of pulling/ pushing down of the divirter built into the spout. The instructions may recommend copper because the tub spout is designed to slip over 1/2'' copper and tighten down with a allen screw(this is to be done after the shower walls have been installed). the 8'' minimum rule is you don't want to get your tub spout and face plate for the shower valve to get to close together (i usually rough mine in at 12'' from center of the valve to center of the pipe for the spout. hope this helps you out.

 

[RustyShackleford]

Yeah, thanks, helps a lot. With the slip-on w/ set-screw, why doesn't water leak out when you activate the shower (since it can't be all that tight a seal that way) ?

Related question: I want to have shower at end of tub as normal, but spout along the long side, so that two people can lean against both ends of tub. Better to have faucets next to spout, or at the end where the shower is ? I figure closer to spout is better, so diverter works the way it's supposed to; but will there be enough pressure/flow at the shower head that way ? Or is it really better to have two faucets (one for shower, one for spout, but more expensive) ?

Thanks.

 

[JJMN]

Adding another shower head you can run into problems with water pressure. Not enough flow when both of them are running. There are three way divirter valves that can be installed into the wall to direct your flow to where you want but they cost just as much as a new shower valve normally. In the situation where people want 2 shower heads I usually put in two valves one for each head. I also run 3/4'' water line to the first valve and tee it off with 1/2'' to feed the 2nd valve. This is for better pressure when both valves are running at the same time.

 

[RustyShackleford]

Sorry, I don't mean two shower heads. I just mean having the one shower head in the usual position at the end of the tub, and the tub-filling spout in the center of the long side of the tub. So it'd be the usual arrangement, except for the slightly odd positions.

I'm wondering if the faucets should be closer to the shower head, or closer to the spout; I'm thinking closer to the spout is better. So then, the only difference (than the usual arrangement) is that the pipe from the valve to the shower will be quite a bit longer. The issue is, would the pressure drop to the shower head be such that the flow is too low ? If I understand, shower flow is limited mostly by the shower head, so if I installed a high-flow shower head, maybe I'd be ok. But if not, I'd consider installing two completely separate valves/faucets, one for the shower and one for the tub spout, if that's necessary to not have the shower flow be too low.

Thanks.

 

[JJMN]

should be fine to plumb it in the way you are talking. although I have never done it that way. I would not worry about the shower head though you would be basically be doing the same thing as a rain shower head that drops out of the ceiling not the wall.

 

[phishfood]

Another reason that they want it piped in copper or galvanized is to avoid the restriction that will be caused if you use PEX with inside fittings. This will cause excess pressure to build up in the area of the valve that transfers the flow from the tub spout to the showerhead, and the shower head will always have a certain amount of flow diverted to it.

 

[RustyShackleford]

I thought about avoiding the problem by putting the shower head above the spout, as usual, except also in the middle of the long side of the tub. Girlfriend did not think that was a good idea.

Starting to realize that a second person (e.g. me) wouldn't want to lean against the drain end of the tub anyhow, even without a tub spout there, because it doesn't have much slope to it.

So I'm back to plumbing it as usual, with the shower head directly above the tub spout, at the end of the tub.

 

[RustyShackleford]

Another reason that they want it piped in copper or galvanized is to avoid the restriction that will be caused if you use PEX with inside fittings. This will cause excess pressure to build up in the area of the valve that transfers the flow from the tub spout to the showerhead, and the shower head will always have a certain amount of flow diverted to it.

Yep, that makes sense. Probably why you see bathtubs where there's some water dribbling out of the shower head even when you're trying to just fill the tub for a bath.

 

[Mr_David]

because you want to relocate the tub spout you can increase the pipe size to reduce the flow restriction of the extra fitting and length of run.

The problem with the spout coming out the side wall maybe hazardous because it would encroaching in to the narrow width of the tub rather than the longer end.

If you stub out copper for a slip on spout use a Threaded female brass back ear or Hyset/Hyco 90 and a male copper adapter and secure it. This way, WHEN, NOT if, you damage the copper stub out with the slip on spout set screw, you can change it with out ripping into the wall.

Only use a galv nipple for temp stub out for tile work. Then replace with brass nipple when installing finish trim.
If you are using a slip on spout install prior to tile work, cap it and leak test it.

 

[RustyShackleford]

Thanks for the tip on replaceable spout stub-out; great idea.

A basic question (I'm DIY) ... In what order do I do the rough-in for spout stub-out ? If I solder the down-pipe to male adapter and screw it onto valve, not sure how to then solder it to the winged elbow without starting a fire. Seems like I have to solder both ends of the down-pipe and then screw the assembly onto the valve, but is there enough slop that I've got a full-turn to make sure the winged elbow lines up right (pointing the right way) ? ANd there's the same problem for the up-pipe to the shower head. Thanks.

 

[Mr_David]

Solder the back ear 90 to copper
Mount the fitting to wood block
Then just set the valve on the top of copper and solder when ready. make sure you have the right rough in depth for valve. You can adjust or plan ahead on block placement.

I some times solder both ends before I mount valve. solder the shower riser in with same fitting. Mount the shower hear fitting and lit the whole thing hang. then secure the tub fitting. now all you have to do is fit up the hot/cold water.

 

[RustyShackleford]

Mr David, I was re-reading your recommendation on the tub spout nipple, and I'm confused ...

You're saying to have the copper downpipe (from the valve) go to a winged/eared elbow just like the one that the shower riser goes to. Then, after the tile work is done, solder the tub nipple pipe to a male adapter, and screw that into the winged elbow (exactly the same as the shower arm screws into the winged elbow at the top). That all makes sense. So what's all this about a temporary galvanized nipple ? Thanks.