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How to Upgrade to a Pressure Balanced Shower Valve

Ask This Old House plumbing and heating expert Richard Trethewey travels to Salt Lake City to replace a shower valve he has never seen before in his career with a conventional pressure balanced one.

Steps:

  1. Start by shutting off the water at the water main.
  2. Find reasonable access to the shower valve. Some houses will have access panels in the room behind the shower valve. In this case, Richard removed a cabinet in the kitchen that allowed them to cut their own access hole.
  3. Trace the outline of the retrofit cover plate over the hole from the old valve. Allow yourself about an inch all the way around for a margin of error.
  4. Cut the fiberglass along the outline of the shower valve using an oscillating saw.
  5. Cut out the old shower valve and pull out the old plumbing. This may require cutting with the oscillating saw or using pipe cutters.
  6. Assemble as much of the valve body assembly as possible outside of the access panel to allow for ease of work. When as much of it has been put together, solder everything together to ensure a watertight seal. This will include: a) cutting the pipes to size; b) cleaning the insides of the fittings and the outsides of the pipes; c) applying flux to the insides of the fittings and outsides of the pipes; d) holding the torch at an angle to heat up the pipe along the joints; e) applying the solder to the joints at the appropriate moment
  7. The solder should appear to suck into the joints when it’s at the right temperature.
  8. Drop the assembly into the access panel and line up the valve body with the center of the hole.
  9. Measure, mark, cut, and solder together the rest of the pipe fittings. This will most likely include a tub spout and the shower head.
  10. Secure the pipes to structure using the pipe clips and a drill driver. If needed, add additional structure in between the joists. This will prevent the pipes from banging around inside the wall.
  11. Connect the pipe assembly to the hot and cold water lines at the appropriate location.
  12. Turn the water back on and check for leaks.
  13. Install the trim over the shower valve.

Resources:

Richard installed a Temptrol Pressure Balanced Tub/Shower Valve, which is manufactured by Symmons. They also manufacture the retrofit cover plate Richard used to conceal the hole left behind from the old valve.

The sink hole cover the Richard used to seal the hole from the old shower head is manufactured by Danco and can be found at home centers.

The other materials Richard used to complete the valve replacement, including the copper pipes, copper fittings, solder and flux can all be found at home centers and plumbing supply houses.


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