+- Woodnet Forums (https://www.forums.woodnet.net)
+-- Thread: Tub/shower valve problem. With solution (/showthread.php?tid=7342487)
Tub/shower valve problem. With solution - MstrCarpenter - 09-15-2018
Last Tuesday I started a one week kitchen remodel that evolved into a bath remodel as well. First day, first comment from customer; " I think I just cracked the tub up stairs". As soon as I dropped the ceiling I knew it had been leaking a long time. Jump forward to Friday night and I'm mostly finished with both projects (including a new ceiling on most of the first floor). Here's the problem; the new Kohler valve came with a pull-up tub diverter, and when it's filling the tub some water also trickles out of the shower head. Kohler customer support, although trying to be helpful, could not provide any answers; at least none that made any difference. I ran into this problem on a previous job with a Moen valve and the (expensive!) solution was to add a whole house pressure reducing valve. That wasn't an option here because "it always worked fine before". So with some advice from a Google forums search, I removed the PEX tube, adaptors and drop ear elbow, and re-piped with a 1/2" CU female adapter, 1/2" CU elbow, and 1/2' CU pipe. Problem solved! I guess that some manufactures include some sort of warning about this in the instructions now. I sometimes actually do read instructions. Like when pictures don't equal 1000 words, and usually when something doesn't work right, I'll read them just to verify that I didn't really need to read them. If Kohler had included this I could have save an hour or more on hold with their "Customer Support"!
In Summary, if the water pressure is high (or really just decent) the pipe and fittings to the tub spout should restrict the water flow as little as possible.
RE: Tub/shower valve problem. With solution - petertay15 - 09-16-2018
Thanks for helping us learn what you discovered, but I need more explanation. WHY was the CU better than the PEX? Which allowed more water flow? Thanks
RE: Tub/shower valve problem. With solution - Mr_Mike - 09-16-2018
Less back pressure.
RE: Tub/shower valve problem. With solution - MstrCarpenter - 09-16-2018
(09-16-2018, 03:51 PM)petertay15 Wrote: Thanks for helping us learn what you discovered, but I need more explanation. WHY was the CU better than the PEX? Which allowed more water flow? Thanks
The outside dimensions of 1/2" copper tubing and its PEX equivalent is 5/8". The inside dimension of type L copper is .545" vs. .485" for PEX. Add to that the fact that the (typical) PEX fittings I used go inside the tube and were crimped on the outside, and there is a substantial restriction to flow. Copper sweat fittings go over the tube and at no point are they smaller than the inside dimension of the copper tubing.
On this install I cut an access panel in the closet wall, cut the shower valve free and pushed on a pair of Shark-Bite ball valves so I could turn the water back on. It was just too easy to use PEX from them to the shower valve, and seeing everything I need is already here, I might as well just use PEX for the shower head and tub spout and leave the soldering box in the truck. it was a perfect application for a saying I frequently tell others; " If you don't have time to do it right, then you certainly don't have time to do it twice!"
All said and done; using PEX and crimp rings instead of sweating copper only saved me about 10 minutes. Material cost would be about the same. Doing it twice took about an extra hour, not including the time spent on the phone, time searching for a solution, and (well spent) time passing on to others the lesson I learned.
RE: Tub/shower valve problem. With solution - Wild Turkey - 09-22-2018
And the second lesson learned about PEX is to use one size larger PEX than copper to avoid such a problem.
RE: Tub/shower valve problem. With solution - MstrCarpenter - 09-22-2018
(09-22-2018, 04:32 PM)Wild Turkey Wrote: And the second lesson learned about PEX is to use one size larger PEX than copper to avoid such a problem.
Even if I found a 3/4" PEX x 1/2" NPT Brass Female Adapter in my plumbing box, I would still need a 3/4" PEX x 1/2" 90* for the spout, and I would still need to sweat at least one joint. The lesson I learned was to just do it all in copper the first time.