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How to Fix a Mixing Valve

A mixing valve is a key component in a faucet or shower; it combines hot and cold water to maintain steady water temperatures. A mixing valve, also called a mixer valve or diverter valve, needs repair or replacement if the faucet handle is hard to move, drips or provides only hot or cold water. Repair or replacement is an easy do-it-yourself project for a homeowner and does not require a plumber.

Repairing a mixing valve can be done yourself.
  1. Turn the main water supply valve in a counterclockwise direction to turn off the water to the faucet, found under the sink or in the basement.

  2. Turn on the faulty shower or faucet to allow the water to drain from the water supply pipes.

  3. Remove the ornamental faucet handle by lifting it off gently with a screwdriver. Many ornamental coverings are made of plastic and do crack or break if you are not careful.

  4. Remove the exposed screw with a screwdriver and lift off the faucet handles on each side.

  5. Locate the nut at the top of the stem and use an adjustable wrench to loosen and remove it from each faucet handle.

  6. Lift the stem out of the faucet to see the mixing valve located directly under the stem.

  7. Take the retainer clip off the mixing valve with a needle-nose pliers by lifting the retainer clip straight up. Find the retainer clip on top of the mixing valve.

  8. Inspect the washers, rings and metal parts for cracks, chips, breaks and signs of wear. Remove damaged parts and replace them. Match parts for replacement at plumbing supply stores or order from the manufacturer.

  9. Wipe the mixing valve with a rag to remove dirt, grime and debris.

  10. Apply a light coat of petroleum jelly on all sides of the rings to lubricate them and allow smooth movement.

  11. Place the mixing valve back into the faucet, reattach the retainer clip, put the faucet stem back in place, tighten the nut, press the handle back in place and turn on the main water supply.

About the Author

Sal Marco began writing professionally in 2009. He has written many online home improvement articles based on his more than 20 years of experience in the home improvement and building industries. He has worked as both part of a team and as a site supervisor. Marco has a Bachelor of Science in management science from Kean University.