A shower valve cartridge is a key component of the shower that controls the mixing of hot and cold water and diverts water to the shower head. Over time, these cartridges can become worn out or damaged and will need replacing. Replacing a shower cartridge is an easy DIY plumbing project that can restore your shower’s performance. This guide will walk you through the steps for replacing a shower valve cartridge.
How to Remove the Old Shower Cartridge
The first step in replacing a shower valve cartridge is accessing and removing the old cartridge. Here is the process:
Turn Off Water Supply
Before doing any work on the shower valve, you need to shut off the water supply. There will be shut off valves somewhere in the lines supplying hot and cold water to the shower valve. Locate these valves and turn them clockwise to shut off the water.
Remove Shower Trim and Valve Access Plate
Most shower valves have decorative trim surrounding the valve and a small access plate that covers the cartridge. Use a screwdriver to remove any screws securing the handle trim and carefully pry it off to expose the access plate. Remove the screws holding the access plate in place.
Remove Retaining Nut or Bonnet
With the access plate off, you will see a large nut or bonnet surrounding the cartridge. Use a wrench or pliers to turn this counterclockwise. In some cases, this nut may be very tight or corroded, so you may need to use penetrating oil or a pipe wrench to loosen it. Keep turning until the nut is completely removed.
Pull Out Old Cartridge
Once the retaining nut is off, you can pull the old cartridge straight out. In some cases, you may need to rock it back and forth gently or use pliers to remove it if it is stuck. Make sure to pull in a straight line and avoid bending the stems. Set the old cartridge aside.
Clean Valve Body
Before installing the new cartridge, inspect the valve body for any signs of buildup or corrosion. Use steel wool or emery cloth to scrub the valve interior and remove any debris. Rinse it out with water.
How to Install a New Shower Valve Cartridge
Once the old cartridge is out and the valve body is cleaned, you are ready to insert the new replacement cartridge. Here are the steps:
Check for Compatibility
Shower cartridges come in many styles, sizes, and configurations. It is important to purchase one that is designed specifically to fit your existing shower valve. Check the manufacturer’s documentation to ensure compatibility.
Lubricate O-Rings
New cartridges will come with rubber O-rings around the inlets to create a water tight seal against the valve body. Lubricate these o-rings with a small amount of plumber’s grease or petroleum jelly. This will allow the cartridge to slide into place easier.
Insert New Cartridge
Carefully insert the new cartridge straight into the valve body, aligning it with the valve inlets. You may need to rotate it gently side to side to get it lined up correctly. Push it all the way in until fully seated.
Reinstall Retaining Nut
Thread the retaining nut or bonnet back onto the valve clockwise. Tighten down firmly with your wrench or pliers to compress the cartridge into place. Do not over tighten.
Reinstall Access Plate and Trim
Put the access plate back, securing with the original screws. Then reinstall the decorative trim and handle set. Insert any screws that were removed and tighten down.
Turn Water Back On
With the new cartridge installed, open the shut off valves to turn the hot and cold water back on. Check for any leaks as the water pressure returns. Tighten any connections if needed.
How to Adjust the New Shower Cartridge
Once installed, you may need to make some adjustments for optimal performance. Here are some tips:
Set Temperatures
Turn on the shower to the hottest setting and let it run for a minute. Then turn to the coldest setting for a minute. This will allow the cartridge to properly align internally.
Balance Hot and Cold Water
The new cartridge may need the hot and cold water flow balanced. Turn on the shower to its midpoint setting. If the temperature is off, shut water off again and adjust the cartridge’s limit stop screws to restrict hot or cold flow as needed.
Replace Seals if Needed
If you notice the shower still has leaks, dripping, or pressure loss after cartridge replacement, the internal seals may need to be replaced. Consult the manufacturer’s instructions to identify and properly replace worn seals.
Install Volume Control Handle
For cartridges designed for separate volume and temperature control, ensure the handle trim has the proper volume control installed to adjust water flow rate.
Clean Valve and Trim
Use mild cleaner or bleach spray to remove any grime or buildup inside the trim pieces. Rinse thoroughly. Buff metal surfaces dry and shiny.
FAQs About Replacing a Shower Valve Cartridge
What are common signs that a shower cartridge needs replacement?
If you notice a sudden change in water temperature, higher water bills, reduced water pressure, leaks, or difficulty turning the handle, it likely indicates a worn out cartridge.
How do I remove a stuck cartridge?
Penetrating oil around the valve body can help free a stuck cartridge. Gently rocking or tapping the cartridge with a wrench may help. Avoid excessive force. Heat from a hairdryer can sometimes break down mineral deposits locking it in place.
Does replacing a cartridge fix a leaky shower valve?
Yes, a leaky shower valve is almost always due to a worn out cartridge. Replacing it will stop the dripping and restore water pressure. Ensure new seals get lubricated properly.
Can I replace just a single cartridge in a dual-valve shower?
Yes, dual-control showers have two cartridges – one for hot and one for cold. They can be replaced independently.
How much does it cost to replace a shower cartridge?
The replacement cartridge itself ranges $15-60 depending on the brand and model. Plumber services to install it range $125-250 per hour. Doing it yourself saves significantly.
What tools do I need to replace a shower valve cartridge?
Basic tools like adjustable wrenches, screwdrivers, pliers, emery cloth, penetrating oil, plumber’s grease, and a bucket. Optionally, a hairdryer. Use a pipe wrench for stubborn cartridges.
Conclusion
Replacing a worn out or defective shower valve cartridge is an essential DIY plumbing skill. With some basic tools and following these steps, you can swap out the cartridge and restore your shower’s performance. Pay attention to compatibility, proper o-ring lubrication, valve body cleaning, and water balancing to ensure optimal results from your new cartridge. Be sure to turn off the main water supply for safety any time you replace a shower valve component.