How to Install a Two Handle Thermostatic Shower Valve With Volume Control

Shut off the water supply to the shower. Remove handles and other trim from the old shower valve. If your wall is tiled, remove tile from the area. Cut a shower valve access hole in the shower wall with the hole saw, just large enough to expose the old shower valve.

Disconnect the old valve from the plumbing by cutting soldered pipes with the hacksaw or undoing threaded connections with the adjustable wrench. Remove the mounting screws holding the old valve to the mounting board. Pull out the old valve.

Mount the new double handle thermostatic mixing valve to the mounting board. The mounting board typically must be 3.5 inches behind the finished wall surface, but that distance will vary from manufacturer to manufacturer. Attach the valve to the board with Phillips-head screws, using the Phillips screwdriver. Most valves will have six mounting screws supplied with the valve. Some manufacturers may use hex-head or slotted mounting screws.

Attach the water supply piping and shower discharge piping to the valve. Attach the hot water line to the inlet port marked “H” and the cold water line to the inlet port marked “C.” Most manufacturers locate these ports on the sides of the valve. Attach the shower discharge pipe to the discharge port at the top of the valve. If your plumbing uses threaded connections, secure the pipes to the shower valve by wrapping the threads on the valve ports with pipe tape, threading the pipe nuts on the ports and tightening the nuts with the adjustable wrench. If your plumbing uses soldered connections, slide the pipes inside the valve ports and solder them to the valve with the propane torch.

If your new valve has a wall trim support plate, install it according to the manufacturer’s directions. Attach the shower valve handles as directed by the manufacturer. Handles typically slide on over a splined shaft and are secured with a screw. Turn on the water supply. Check for leaks. Operate the on/off/volume control and the thermostatic temperature control to check for correct operation. Remove the valve handles.

Repair the hole in the shower wall, using the valve manufacturer’s template to locate the holes on the wall repair piece. Reinstall tile or restore other shower wall finishes. Install the shower valve wall trim as directed by the manufacturer. Trim typically is clipped or screwed to the valve, or is held in place by the valve handles. Reattach the valve handles.