Shower faucet valves can be kept in good working order for a long time by periodically repairing or replacing the internal parts, but sooner or later you'll probably want to replace the entire valve with a new model. For example, you may want to install a new temperature-balanced, anti-scald valve, which offers better safety for your family. Replacing the shower valves can also be a very good home improvement to make if you are prepping your house for sale.
Replacing a shower valve can be tricky since access to the valve is often quite restricted. The original shower valve may have been installed during the rough-in phase of the wall construction, when the studs were exposed. Now, your only access to the valve may be through the small wall opening that is exposed when the valve's cover plate is removed. If you are lucky, you may have a rear access panel that exposes the shower's plumbing connections, but this is not something you can count on.
Further, most shower valves are installed with copper fittings that are sweat-soldered using a propane torch. This requires a lot of caution when working around wood framing. A DIYer should have good experience with sweat-soldering copper in other applications before pointing the nozzle of a red-hot torch into a wall cavity.
Finally, because access is so limited, installing a new shower valve often leads to some amount of wall demolition and repair. More than one DIYer has found himself unexpectedly tearing out sections of tile shower wall in order to get the new shower valve installed. The risks can be minimized if you make sure to choose a new valve that is roughly the same shape and size as the old valve, but you should be prepared for this project to become more complicated than you expected.
Equipment / Tools
- Copper tubing cutter
- Propane torch
- Spray bottle
- Fire extinguisher
- Inspection mirror
- Protective gloves
- New shower valve
- Lead-free solder
- Emery cloth
Remove the Old Valve
Begin by turning off the water and removing the old shower valve. Sometimes the easiest way to do this is by heating up the pipe fittings with a torch in order to loosen the solder and pull the valve free. If you do this, make sure to wipe off as much of the liquified solder as possible. Be careful not to burn yourself when you do this and keep a spray bottle and fire extinguisher handy whenever you use the torch.
Or, it may be easier to cut off the pipes as close as possible to the old valve, using a hacksaw or copper tubing cutter. Whatever method you use, smooth the exposed hot and cold pipes with emery cloth after extracting the old valve, making sure the copper is clean and shiny and free of solder and burrs.
Disassemble the New Valve
Remove the plastic cartridge and any housing from the valve body before beginning installation. These plastic components cannot stand up to the heat of soldering. Keep track of how the cartridge came out because you'll need to put it back in so it faces the same direction.
Prepare the Valve
Before putting the shower valve in the wall, make any necessary preparations necessary. For example, if the valve will go into a shower without an attached bathtub (such as in this example), the bottom of the valve needs to be capped. Capping the bottom outlet is normally done by soldering a copper cap onto the opening. Let the valve cool before moving on to the next step.
- Note: Make sure not to cap the wrong end of the valve (the bathtub outlet can look exactly like the shower outlet). Position the valve so that the part that reads "SHOWER" or "UP" is facing up.
Apply flux (soldering paste) to all of the pipe sockets on the valve and to the end of the hot and cold water pipes before proceeding.
Position the Valve
Maneuver the valve into position inside the wall. Sometimes it's difficult to get the valve into place, so be careful not to drop the valve as you position it inside the wall.
- Tip: Some people like to tie wire onto the valve so it can be easily retrieved if it is dropped inside the wall.
It is often easiest to put the valve onto the shower riser pipe first, then pop the old and hot water pipes into the side inlets on the valve. Be certain that the copper pipes are seated fully into the valve sockets before soldering them.
Solder the Fittings
Light the propane torch, adjust the flame, then proceed to soldering each of the joints. Be extremely careful when soldering in tight spaces, and make sure to have a spray bottle of water and a fire extinguisher ready. It can also help to wet the wall a bit first with the spray bottle.
Focus on one joint at a time and make sure the solder flows completely around the joint, especially on the backside where it's hard to see. Since these pipes are usually only 1/2 inch in diameter, you don't need a big flame. An inspection mirror will allow you to see if the solder flowed all the way; touch up an area if needed before turning on the water supply.
Install the Valve Cartridge
Allow time for the pipes and the shower valve to cool down after soldering before reinstalling the shower cartridge. When the metal is completely cool, reinstall the shower cartridge the same way as it was removed.
Make sure that the shower valve is in the OFF position; then turn the water back on and check for leaks. Make sure there aren't any leaks in the shower riser as well.
Lastly, install the trim and handle. Position the cover plate, then screw on cartridge sleeve. The handle goes on last.