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How to Tell If a Shower Mixing Valve Is Bad

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The shower mixing valve is an important part of your shower system. It allows you to control the amount of hot and cold water and adjust the water temperature easily while taking a shower. However, it can become faulty and make your showering experience uncomfortable.

In this article, we’ll discuss how to tell if your shower mixing valve has become bad, along with an easy solution to fix this problem.

How to Tell If a Shower Mixing Valve Is Bad

If you experience any of the following problems, it means your shower mixing valve isn’t working properly and needs to be fixed.

Water Temperature Problems

Experiencing water temperature problems is one of the most common signs of a faulty shower mixing valve. It usually happens when your shower valve becomes damaged, blocked, or dislocated.

When this is the case, the valve fails to regulate the temperature correctly and starts showing one or more of the following issues.

Constant Fluctuation in Water Temperature

The first thing you need to do is to check other faucets of your house if you experience constant fluctuation in water temperature while taking a shower. If other faucets are running as they should, the problem is with your shower mixing valve.

However, if other faucets are having the same problem, then the problem lies within the hot water supply of your house.

Running Hot Water Permanently

Another common temperature problem with a faulty mixing valve is that it starts running only hot water. It doesn’t offer cold water, making it difficult to take a shower. It usually happens when the cold side of the valve has become blocked.

Running Only Cold Water

In most cases, the shower stops running hot water and offers only cold water because of a faulty water heater. So, you’ll need to inspect your water heater to make sure it’s running properly. You can also check other faucets to see whether they’re running hot water or not.

If your water heater is working and you’re getting hot water from other faucets, then the hot water side of the valve is damaged, dislocated, or blocked.

Cold Water from Hot Side

Your shower will offer hot water from the cold side and vice versa when the valve is flipped 180 degrees. It usually happens when you install a new mixer valve with the bottom side up. As a result, your hot side becomes cold, and the cold side becomes hot.

Stiff Shower Handle

The water running in your shower contains a lot of minerals. Over time, these minerals can lead to corrosion and mineral buildup in the shower handle or valve.

As a result, you find it difficult to turn the shower handle. It’s also a common sign indicating that your shower mixing valve needs attention.

Showerhead Dripping Constantly

A constantly dripping showerhead might not seem like a big problem, but it can’t be overlooked. According to the EPA (Environmental Protection Agency), a single faucet dripping only one drop a second can waste over 3,000 gallons of water per year.

It simply means that it’s the money going down the drain that you can save. This problem often occurs due to a damaged or misaligned valve that can’t shut running water off effectively.

Reduced Water Pressure

The most common reason why you experience reduced water pressure while taking a shower is a partially blocked showerhead. You can simply use an old toothbrush or toothpick to remove the blockage.

However, the same problem can also occur due to a bad shower mixing valve. When the valve is misaligned or damaged it fails to turn completely, giving a narrow passage for water to run.

How to Fix a Bad Shower Mixing Valve

The easiest way to fix a bad shower mixing valve is to replace the faulty valve with a new one. You can use the steps listed below to achieve that.

  1. Shut off the water supply of your bathroom.
  2. Wear rubber gloves to ensure the safety of your hands.
  3. Locate and remove the set screw securing the shower handle. It’ll be located beneath the handle’s index button or the bottom side of the handle’s lever.
  4. Remove the shower handle by pulling it outward. If you find it difficult to remove, consider applying WD-40 and waiting for three to five minutes. It’ll break the corrosion inside and allow you to remove the handle easily.
  5. Inspect the shower handle and if it has corrosion and mineral buildup, use calcium lime rust remover to clean it.
  6. Now, unscrew the two screws securing the front metal plate of the shower handle system and remove it.
  7. Remove the shower faucet sleeve covering the mixer valve.
  8. Grab pliers with pointy ends to remove the retaining clip located on the top side of the valve’s housing.
  9. Use pliers with rubber jaws to grab the valve’s stem pointing outward and pull it away from the wall to remove it. Make sure that you grab the shower valve pipe with your other hand to keep it from damaging.
  10. If your hot and cold sides are reversed, flip the valve to 180 degrees and insert it in its place. You can also apply some grease on the O-rings of the valve located on its sides. It’ll allow you to remove it easily if needed in the future.
  11. If your valve is faulty, you’ll need to replace it with a new one. Keep in mind that different showers use different valve types. You’ll need to buy the correct one designed for your shower system.
  12. Insert the new valve into the pipe. Make sure that you insert it with the correct side up with the help of the “H” (for hot) and “C” (for cold) letters printed on it.
  13. Reinstall the retaining clip and faucet sleeve back to their places and secure the metal plate and shower handle using screws.

Final Words

A shower mixing valve blends hot and cold water and allows you to control the water temperature depending on your needs.

But sometimes it fails to work properly because of a faulty valve and you’ll need to replace or adjust it to solve the problem.

We hope this guide will help you understand how to tell if your shower mixing valve is bad and how to fix it.

Allen Michael is the Founder and Editor of Home Viable, a website that he started to provide readers with tips on home efficiency and automation. He draws on his engineering background combined with his family-of-four experiences for his articles.