How to Replace a Compression Shut-Off Valve in Copper Plumbing
Overview
Replacing a compression shut-off valve is a relatively easy task that can be completed in about 20 minutes. It’s a good idea to replace shut-off valves when you’re replacing other plumbing fixtures, such as toilets or faucets, to ensure they’re working properly.
Materials and Tools
- New compression shut-off valve
- 2 channel-lock pliers
- Tubing cutter (optional)
- Compression sleeve puller (optional)
- Rag
Safety Precautions
- Turn off the water supply at the main shut-off valve before starting any work.
- If you’re only replacing a hot-water shut-off valve, you can turn off the hot water at the water heater.
- Wear safety glasses and gloves when working with plumbing.
Step-by-Step Instructions
1. Remove the Old Valve
- Disconnect the flexible supply tube from the outlet nipple on the shut-off valve.
- Grip the valve with one pair of channel-lock pliers and turn the compression nut with another pair of pliers to loosen it.
- Slide the valve body off the end of the water pipe, then slide the compression ring and compression nut off the pipe.
- If the compression sleeve is stuck on the pipe, use a tubing cutter to cut back the copper and install the new compression valve on a new section of pipe.
2. Install the New Valve
- Clean the pipe with a rag.
- Slide the new compression nut onto the pipe, followed by the compression sleeve.
- Slide the valve onto the water pipe, making sure the pipe is fully seated into the valve’s socket.
- Slide the compression ring and nut up against the bottom of the valve and thread the compression nut onto the valve body.
- Tighten the nut as far as it will go by hand. Holding the valve with one pair of pliers, tighten down the compression nut with another pair of pliers. Another one-quarter turn of the nut with pliers is usually sufficient to fully tighten it.
- Reattach the flexible water supply tube to the outlet on the valve. Tighten fully by hand, then another one-quarter turn with pliers.
3. Turn On the Water and Check for Leaks
- With the shut-off valve fully closed, turn the water supply back on at the main shut-off valve.
- Check for leaks at the compression fitting on the valve.
- Slowly open the new shut-off valve while continuing to look for leaks at both the compression fitting and the flex tube fitting.
- If you see any water seeping, tighten down the nuts a little further until the leaking stops.
Troubleshooting Tips
- If the compression sleeve is stuck on the pipe and cannot be removed with pliers, use a compression sleeve puller.
- If you notice a leak after installation, shut off the water, remove the pressure from the line, then tighten the compression nut a little more and recheck it.
- Compression valves can sometimes have slow leaks. Check back a few times in the hours after installation to make sure there is no seeping water.