Connecting Tub/Shower Valve to Spout Without Solder
etting
| Posted in Mechanicals on
I gather that 1/2″ PEX isn’t suitable to connect a tub/shower valve to the tub spout because the internal diameter of the PEX and especially its fitting is too restrictive, which will cause the shower to dribble while using the tub spout. The usual solution is to solder copper into the drop-ear elbow that holds the tub spout, but for those of us without that equipment and nothing else in the entire house to solder, I have found two alternatives:
1. Use a 3/4″ PEX crimp to 1/2″ FIP adapter at the valve and a 3/4″ PEX crimp to 1/2″ FIP drop-ear elbow to hold the tub spout (with 3/4″ PEX between them, of course).
2. Use the Sharkbite Shower/Tub Installation Kit, which push-connects onto 1/2″ hard copper between the valve and the spout.
The Sharkbite product is made for people like me who don’t want to sweat the copper, but might the 3/4″ PEX solution have the advantage of not depending on perfectly round copper or the reliability of push-connect fittings? The 3/4″ PEX crimp fittings may have a larger internal diameter than the 1/2″ Sharkbite as well.
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Replies
I don't think you'll have any real issue just using 1/2" PEX. Many think that the smallest diameter "thing" anywhere along the line sets the maximum possible flow rate for the entire system, but that's not really true. Both the diameter AND the length come into play, and it's typically the restriction of the pipe itself that dominates. The reason for this is that there are frictional losses in any pipe, and this also restricts flow. For a run of any length, it's the flow restriction -- head -- of the pipe itself that tends to dominate the overall system, so a fitting with a smaller ID than the pipe itself but a VERY short overall length doesn't really do much to the flow rate of the entire system. Unless you have a very short run of 1/2" PEX (such as a foot or two branch line off of a larger main), the fitting's added restriction will be negligable as a percentage of the overall restriction to flow in the system.
I'm not a fan of sharkbite fittings except for temporary applications. Sharkbite fittings are excellent (maybe beyond excellent) for emergency repairs, and capping of a damaged pipe in a hurry. For a permanent fitting, especially in an inaccessible location, I would stay with compression fittings that don't rely on o-ring seals. For this reason, I'd got with your option #1 if you're really worried about that 1/2" fitting.
Bill
> 1. Use a 3/4″ PEX crimp to 1/2″ FIP adapter at the valve and a 3/4″ PEX crimp to 1/2″ FIP drop-ear elbow to hold the tub spout (with 3/4″ PEX between them, of course).
I suspect it will work, but don't blame me if your shower head drips. :-)
You could also use a brass or stainless nipple and elbow.
No need to oversize the pex, just half inch to the drop ear. Use a threaded drop ear and a brass nipple if you don't want to solder.
The drop ear has to be quite stoutly attached, at some future date some poor soul will be leaning on a pipe wrench trying to get the spout off. What can be tricky is getting the length of the nipple right, it has to go in before the backer board and tile. The spout to nipple junction doesn't have to be particularly water-tight but there needs to be enough thread to hold the spout firmly.
A trick I've learned: if the closest nipple is just a little bit too long for the spout to meet the tile, and the next shorter size is too short to grab the thread in the spout, don't overtighten the spout to try and close the gap, you'll crack it. Instead, you can make the spout come a little bit closer by using a tapping die to deepen the threads. Each revolution gains 1/16".
Jeff,
I'd go with your first option using 3/4" pex - although the supplies needed to solder it only set you back less than $30.
Thank you, all. You seem to agree that PEX is the better idea, as I have thought as well. Faucet manufacturers like Delta say, "Do not use PEX tubing for tub spout drop," but from everything I've read, they're basing that on the restriction in 1/2" PEX, which the 3/4" would seem to solve, an option they may not have considered because the 3/4" PEX to 1/2" FIP fittings are available from so few retailers.
Restriction has nothing to do with it. I think you're completely misunderstanding. The "drop" is the portion that sticks out of the wall. It has to be a rigid material because it physically supports the spout, people will lean on it.
With respect, DCC, I think you're mistaken. The drop, according to everything I've read and several illustrations from manufacturers, is the section of pipe that drops from the valve to the drop-ear fitting that holds the nipple that holds the spout. Why would a horizontal segment be called a "drop"? Of course no one would imagine attaching a tub spout to a piece of PEX sticking out of the wall!
https://media.deltafaucet.com/MandI/50353%20Rev%20L.pdf
I just found this too, a copper stub-out with a 1/2" FIP to attach to the valve.
https://www.supplyhouse.com/Sioux-Chief-613-67F-1-2-FIP-Copper-Tub-Spout-Stub-Out-Elbow-6-x-7
It's the only one of its kind and only available from two retailers, apparently, but if 6" is enough height and I don't mind a slide-on/slip-fit spout, it looks like a good solution, although it wouldn't be as secure against side-to-side stresses as a drop-ear elbow well attached to wood. No one makes drop-ear elbows that will accept a threaded drop.
Any thoughts on how this compares to the 3/4" PEX alternative described above?
Jeff,
That elbow will be fine. The only drawback is having the threaded piece already attached means you are limited in how far you can tighten it, as the spout has to align with the tub.
Good point, Malcolm; thank you. I also get the impression, although I haven't read about it extensively, that those slip-fit spouts are more troublesome than the screw-on kind.
Jeff,
I find the opposite. To get the screw on ones flush to the tile or other surface you again are left with one complete turn, that can either leave it proud or too tight. The allen-key on the slip type keeps it in place and upright.
I would agree. And as far as a seal goes (so water doesn't creep back around the pipe), the o-ring in the slip joint is under nearly zero pressure because of the relatively massive opening of the spout itself.
>And as far as a seal goes (so water doesn't creep back around the pipe), the o-ring in the slip joint is under nearly zero pressure because of the relatively massive opening of the spout itself.
It depends upon the type of diverter. If the diverter is inside the valve, that's true. If the diverter is in the spout, then the spout holds the full pressure of the water.
Here is a FIPxFIP drop elbow:
https://www.amazon.com/DROPEAR-JMF-COMPANY-MfrPartNo-4507034/dp/B008ROMKA4/ref=sr_1_11?crid=1KPVD3A3GMSX9&dchild=1&keywords=drop+elbow+1%2F2&qid=1611198463&sprefix=drop+elbow%2Caps%2C152&sr=8-11
You could use that with a brass nipple.
Thank you, DCC! I couldn't find one of those; I was probably tired and looking just at SupplyHouse, which seems to have everything. Good point about the diverter on the slip-fit spouts too.
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Thank you, Malcolm and Patrick. That makes sense.
If you're not comfortable soldering copper why not just use pvc...two half inch male adapters and a 90......
You would need to use CPVC for this since it could potentially be considered a "hot" water line.
I'd use copper here myself. Originally I'd thought the OP was asking about the supply lines. For the short run between the valve and spout or shower head, copper offers some extra durability over the other options since it's rigid but not brittle.
Bill
Once you have the rigid 1/2" copper protruding from the wall, Delta's hardware is the best.
This video mentions the Delta slip-on-set-screw version at 2:20, and proceeds to show the Delta pipe thread version using a compression fitting (both methods are solderless).
https://www.youtube.com/watch?v=StT0dXsxEBA
These spouts always need replacing after 8-20 years because they are zinc die castings that corrode and fail.
The brass Delta adapter is the best solution for that future repair or remodel. It has an o-ring seal and parallel threads that tolerate inaccurately cut pipe lengths or a new tile thickness. The set screws in the other slip on methods will soon be inoperable due to corrosion. The pipe threads in all the other tapered thread methods will usually be seized (zinc corrosion), so you'll twist the copper pipe which destroys it and causes about 3 more hours of work. If you are lucky enough to unscrew the non-Delta spout, the protruding pipe is unlikely to be the correct length.
I would take it your valve to a local plumbing shop. If you can find a smaller family owned shop or a shop that does mostly residential work they would solder it or press it for next to nothing. A couple tied and true solder joints would be my preference. I can tell you from experience that even the best expandable PEX if used between a valve and tub spout will cause enough back pressure to dribble out the shower head. We have DIY customers that want things made in the metal
Shop or prepped for their home projects. We have a discounted shop rate for this work since we don’t have to leave the shop and because it’s great filler work if a service guy has a free hour at the end of the day
I just want to make sure I understand this correctly, as I don't normally deal with tubs and am looking at one now.
You're saying that the 0.385" internal diameter of a ½" F1960 (expansion) drop ear creates enough pressure to flow some water up and out of the shower head ?
Thank you, all. I chose to use a brass nipple to drop from the valve to a FIP x FIP drop-ear fitting.
Interesting about the Delta spout, Kevin. I'll check it out. It sounds as if an anti-seize compound would be advisable with any other ones.
Jeff,
Now you can come out of the wall with another brass nipple and have a very rigid assembly.
Thank you, Kevin; yes, that's what I'm doing.