Plumbing Kohler Ceiling Tub Filler K-922

9 years ago

Anyone have experience installing this laminar flow tub filler?

My challenge:installing tub filler into a log extending across a kohler sok tub. The tub extends into an alcove and abuts a shower enclosure which limits options for valve and filler location.

Leaving the woodworking out of the conversation the three things I'm trying to resolve are:

1) Pipe sizing requirements between the Kohler K-2971 (Hi Flow/Rite-Temp) valve and the K-922 tub filler. Specs state that K-922 requires 5-8 gal/min for the laminar flow to work correctly. The K-2971 valve has 3/4" inlet size for both cold and hot and a 3/4" outlet heading toward the tub filler. I'm surprised to see that the tub filler inlet port is only 1/2". At which point should I reduce the pipe sizing between the two fixtures? Does it matter? I need to get the best flow possible at the outlet.

2) Do I have options in selecting the pipe to use? Kohler literature states copper pipe between valve and outlet (no PEX?) - can I consider a flexible copper pipe or must I do this with rigid copper pipe? If flexible copper pipe can be used, which fittings are appropriate for flexible copper pipe?

3) The only location for the on/off valve is in the wall within reach of the inside of the tub. (Kohler states that valve can not be deck mounted when installing the ceiling filling option). This is an exterior wall (2" x 4") so I am concerned about freezing. Any ideas for mitigating risk of freezing?

Sort by:Oldest

Comments (2)

aramendiadallas132
9 years ago
I had read your post. Yaah I can help you mate. 1 year back I also did my plumbing of my home. It was really a great work by them. I can give you the contact details of them. aramendiadallas.com, you can check the website of a good plumbing department which had done my plumbing work too.
Eric Newman
9 years ago
Thank for your response aramendiadallas132.

I'm doing a follow-up in case it may be helpful to someone in the future...I ended up doing a couple mockups using both PEX and 3/4" copper between the Kohler K-2971 (Hi Flow/Rite-Temp) valve and the K-922 tub filler. I did get nominally better flow with the 3/4" copper. I was filling a 5 gallon bucket and the difference in fill times was 48 seconds vs 52 seconds with the PEX. Most importantly I was able to get the solid crystal rod of water between the tub filler and the floor - no break up of the water column with either. Since I did meet the flow rate goal, I used PEX in the log installation. I brought the 3/4" pipe all the way to the point that the K-922 inlet pipe and dropped to 1/2" there.

I had been concerned about installing the mixing valve in the exterior wall. The K-2971 is a nice piece of machined brass but it is 3 1/2 deep - the back of the valve was to be against the exterior sheathing. I ended up ripping 2 x 4s and packing out that wall an extra 1 3/4" which allowed me to install 1 1/2" of rigid foam insulation (approximately R-9) between the valve and the sheathing - not ideal but I'm comfortable with it.

The piping extends into the log and the tub filler drops the water in a crystal column.
Related Professionals
Millbury Handyman · Shamong Kitchen & Bathroom Remodelers · Allouez Kitchen & Bathroom Remodelers · Boca Raton Kitchen & Bathroom Remodelers · Bremerton Kitchen & Bathroom Remodelers · Brentwood Kitchen & Bathroom Remodelers · Fort Pierce Kitchen & Bathroom Remodelers · Gilbert Kitchen & Bathroom Remodelers · Jefferson Hills Kitchen & Bathroom Remodelers · League City Kitchen & Bathroom Remodelers · Mooresville Kitchen & Bathroom Remodelers · Richland Kitchen & Bathroom Remodelers · Spokane Kitchen & Bathroom Remodelers · Upper Saint Clair Kitchen & Bathroom Remodelers · Middlesex Kitchen & Bathroom Remodelers