shower valve torque specs for 1/2" solder fittings

[rfsmith48]

So I am installing a new Kohler K304 shower valve.

What torque value should I use for the 3 1/2" solder fittings, and the 1/2" cap for the tub outlet?

TIA,

Rog Smith

[hj]

There is no such "value". You turn them until they are tight, or VERY tight.

[jadnashua]

Most of those valves will accept either a directly soldered in pipe, or a female threaded fitting...pros almost always use the soldered connection. The threaded connection is made by jamming the threads with a sealant in between the male and female parts. It gets tighter (think wedge) the more you screw it in. It really depends on the quality of the fittings, and the type and quantity of sealant.

[Gary Swart]

As previously stated, there are two ways to do this. You can sweat the pipe directly to the valve, but these is a risk involved, especially for a novice. Get the valve too hot and it's toasted. The second way, the safer way, is to sweat a male adapter to a short length of copper pipe. Then screw the adapter into the valve following HJ's suggestion. Tight or tighter and use some pipe dope. Now, you can sweat fittings on the other end of the copper pipe without overheating the valve. With little planning you won't have to make a second cut on those short pieces of pipe.

[jadnashua]

FWIW, pipe threads are not like torquing the head bolts or wheel bolts on a car where a specific torque can be determined to work...there's no gasket to compress...the threads are tapered and when tightening the fitting, you are literally jamming the male and female threads, not compressing two flat surfaces of a gasket. The sealing material must be applied properly, as the threads just make the mechanical connection, not the seal.

[takatsu]

Hi! I had the same experience. After two different types of pipe dope (a generic hardware store and a brand-name) leaking after a few hours or days, I took out the valve with female fitting and bought a valve with male fittings so I could solder it in place. Maybe some people can get dope to work correctly, but not me. Then I read on this forum that the big boxes sell female valves because they have to be used with dope/male pieces specifically to avoid soldering- consumers didn't take the plastic and rubber pieces out of the valves before soldering, melted them, and returned them to the store (who sent them back to the manufacturer). So the shower valve manufacturers passed their problems on to the consumer by only offering female valves in big box stores. Apparently, a plumber will take a male/solderable valve over a female/dope valve any day of the week. After my experience- me to. The original valve soldered into my shower when then house was built in 1980 looked much the same as I expect it did then when I opened the wall 30+ years later- no leaks and just a bit dusty.

[jadnashua]

Many of the valves can be used either way...