How to Install a Shower Control Valve

Mixer valves control hot and cold water before it reaches the shower head.

Shower control valves---known also as mixer valves---moderate the amount of hot and cold water that reaches the shower head. They are manipulated by either hot and cold knobs, or one single dial. The mixer valve has two inlets on its bottom for hot and cold copper supply pipes to be attached to. It also has an outlet on its top for a single copper pipe to be attached to, that reaches up to a brass fitting that holds the shower head and arm in place. Both inlets and outlet are soldered to the control valve.

Things You'll Need

• Galvanized screws, 2-inch
• Drill gun
• 2-by-4 wall stud
• Mixer valve kit (including brass shower head fixture)
• Copper pipe
• Tubing cutter
• Emery cloth
• Soldering paste and brush
• Propane torch
• Roll of solder
• Rag
• Water spray bottle

Instructions

1. Attach the shower valve with 2-inch galvanized screws to a horizontal piece of 2-by-4 wall stud. This stud will in turn be attached between two vertical wall studs, also with screws. Refer to the valve/shower handbook regarding the required height/position of the valve on the shower wall.

2. Sand the insides of the inlets on the valve's bottom and the ends of both hot and cold copper supply pipes, using emery cloth. Attach hot and cold copper water supply pipes to the inlets.

3. Cut a piece of new copper pipe to run from the valve's outlet on its top up to the brass fitting that holds the shower head and arm in place--refer to the mixer valve manual for the correct height of the brass fitting. First measure the required length of the copper pipe, and mark the pipe where it needs to be cut. Place a tubing cutter around the pipe--tighten the blade onto the mark. Rotate the cutter 360 degrees. Tighten the blade again. Rotate again. Continue in this fashion until the pipe is cut through.

4. Sand both ends of the new piece of pipe, the brass shower head fitting's inlet, the mixer valve's inlets and outlet, and the ends of the copper supply pipes that will enter into the valve inlets.

5. Brush a thin layer of soldering paste (flux) onto all sanded areas.

6. Push the copper supply pipes up into the mixer valve's inlets. Push the new copper pipe into the mixer valve's outlet. Push the other end of the new pipe into the brass shower head fitting's inlet.

7. Uncoil 12 inches of solder from its roll. Bend the last 3 inches 90 degrees. Turn on the propane torch.

8. Apply heat to one of the valve's inlets. Move the flame from side to side, and heat the back also. When you hear the flux sizzling, touch the tip of the solder to the seam between the pipe and valve inlet. Apply 3/4 inch of solder around the seam. Wipe away any excess solder using a rag (it will be hot). Now solder the valve's other inlet, its outlet, and the shower head brass fitting's inlet in the same way. Once the pipes have cooled, water can be turned on.

Tips & Warnings

• Before installing the mixer valve, both hot and cold water supply pipes will have to be run to the valve location, so they can be attached and soldered to the valve inlets. Before this, the water will have to be turned off at the main shut-off valve.

• When soldering, be aware of flammable objects, and have a water spray bottle on hand in case of emergency.

References

• "Home Improvement 1-2-3"; Benjamin W. Allen, Christopher Cavanaugh; 1995