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How to Install a Water Pressure Reducing Valve

Taming extremely high water pressure with This Old House plumbing and heating expert Richard Trethewey

In this video, This Old House plumbing and heating expert Richard Trethewey tame extremely high water pressure.

Steps for Installing a Water Pressure Valve:

  1. To determine the incoming water pressure, attach a pressure gauge to a hose sillcock or other valve with a male threaded connection.
  2. Ideal house water pressure is about 50 pounds per square inch (PSI). If the pressure is excessively high, install a pressure-reducing valve.
  3. Using threaded pipe and fittings, attach a pressure gauge to each side of the pressure-reducing valve.
  4. Hold the valve assembly against a water pipe and mark where to cut the pipe.
  5. Shut off the water to the house, then drain water from the plumbing system.
  6. Use a tubing cutter to remove a section of water pipe, as indicated by the marks made in Step 4.
  7. Remove the pressure gauges and rubber O-rings from the valve assembly.
  8. Brush flux onto the ends of the valve assembly and onto the ends of the water pipe.
  9. Solder the valve assembly to copper water pipe.
  10. Once the assembly has cooled, reinstall the pressure gauges and O-rings.
  11. Turn the water back on and read the pressure gauge on the outgoing side of the valve.
  12. If the water pressure is too high—that is, above 50 PSI—turn the adjusting screw on the valve in a counterclockwise direction.
  13. If the water pressure is too low, turn the adjusting screw in a clockwise direction.

Tools: