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HERE'S HOW- Replace a Shower Mixing Valve With a New One PDF Print E-mail
Written by Pat Logan   
Thursday, 03 January 2013 02:52

Dear Pat: Whenever one of the kids flushes a toilet while I am showering, the water gets very hot. Would installing a new type of shower valve help, and can you give me some doit- yourself tips? — Melissa B.

Dear Melissa: This is a very common problem when your bathtub has the old two-handle (hot and cold) shower valve. When a toilet is flushed or the cold water faucet in the kitchen is opened, the pressure drops on the cold water side. This changes the shower water mixture, allowing much more hot water into it.

The simplest solution to this problem is to install a singlehandle shower mixing valve with a pressure-balancing feature. The valve is designed such that if the cold or hot water pressure drops, the mixture still stays relatively balanced. You may still feel a slight change, but it will not be uncomfortable. Even with the hot water heater tank temperature set at normal levels, your skin can become scalded from hot shower water. This is a more serious problem with the elderly. They often are not as sensitive to the temperature changes and they may get scalded without sensing the pain soon enough.

If you can solder a copper pipe, you should be able to install a pressure-balancing mixing valve yourself. A decent quality valve will cost about $125. The most difficult aspect of this project will be gaining access to the old valve inside the wall.

There are two directions, from inside the shower stall or from the wall outside the bathroom, to reach the old valve. If you have access to the wall outside the shower, cut through the drywall to get to the valve. If you make a careful cut, you should be able to replace the same piece of drywall when you are done.

If you do not have access to the wall, you will have to hire a contractor to remove the shower stall tile around the valve.

Unless you are experienced with tile, don't try this yourself, or you will likely break some of the tiles. When you are done, replacing the tiles and grouting them is not difficult.

Remove the knobs and pry off the cover plates in the shower. Be careful not to damage the tile. If you plan to use the same tub spout again, wrap it with a thick cloth and carefully unscrew it using adjustable pliers. Make the opening in the wall.

Use a tubing cutter to cut the copper hot and cold water supply lines and the pipes to the spout and the showerhead. There often is very little depth to work in, so use a mini-cutter. Ridgid Tools makes an inexpensive one that you can find at most home center stores. Cut the two supply lines at the same height to facility installing the new pressure-balancing valve.

Remove the old valve. Fit the new valve in place, and measure the lengths of pipe you will need to connect it to the existing plumbing. Dry fit it all together first before doing any soldering. If everything fits properly, remove it, and sand all the mating copper surfaces.

Apply flux, assemble it and solder the joints. Install a large chrome cover plate, sometimes called a goof plate, over the tile to cover the two old handle holes.

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Last Updated on Thursday, 03 January 2013 02:56