Compression shut-off valves are used with copper pipes to create a watertight seal. A compression sleeve fits in a coupling nut, which screws onto the valve body. The brass sleeve compresses against the copper pipe as the nut is tightened. Fortunately, this is a simple process. Most people can learn how to replace a compression shut-off valve. We’ll explain below.
What to Know When Purchasing a Compression Shut-Off Valve
Shut-off valves for fixtures come in different sizes. Measure the size of the pipe diameter to determine the size of the valve you need. The inlet size and the pipe diameter must match, while the flexible water supply tube and valve outlet must also be equal in diameter. If you buy the wrong-sized valve, it will not fit correctly onto the pipe, if at all, or it may leak.
In addition to a new compression shut-off valve, you will also need the following:
- Adjustable wrench
- Channel-lock pliers
- Pipe cutter
- Deburring tool
- Compression sleeve puller
- Emery cloth/pipe cleaner
Steps to Compression Shut-Off Valve Replacement
Now we will explain how to replace a compression shut-off valve:
- Turn Off Your Main Water Supply: The main valve is usually near the water meter. Turn off only the hot water at the water heater if replacing only the hot-side valve (it’s recommended to replace both the hot and cold side valves). Place a bowl or towels under the pipe before you start removing the old valve.
- Remove the Old Shut-Off Valve: Be careful when removing the old valve to avoid damaging the pipe. Any dented copper will need to be cut, and the new pipe end will need to be cleaned and deburred. To remove the valve:
a. Grip the valve with channel-lock pliers and turn the compression nut with another pair of pliers.
b. Slide the brass compression ring and compression nut away from the pipe.
c. If the pliers don’t work, cut back the copper with a tubing cutter.
d. A compression sleeve puller can be used if the sleeve won’t budge with pliers.
- Prepare to Install the New Valve: Clean the surface of the pipe, using a pipe cleaning tool or emery cloth to remove paint, grease, and buildup. Then deburr the inside and outside of the pipe. Finish cleaning the pipe with a rag.
- Install the New Compression Shut-Off Valve: Once the old valve, sleeve, and compression nut are removed, and the pipe is cleaned, install the new valve you purchased (preferably a quarter-turn ball valve), following these simple steps:
a. Slide the new compression nut onto the pipe.
b. Slide the compression sleeve over the pipe.
c. Slide both down to accommodate the valve.
d. Slide the valve onto the pipe, which should be fully seated into the valve socket.
e. Slide the compression ring and nut against the bottom of the valve.
f. Thread the nut onto the valve body and tighten it as much as possible by hand.
g. Hold the valve with a pair of pliers, and tighten the nut with another pair.
h. Attach the flexible water supply tube to the valve’s outlet.
i. Tighten by hand and a quarter turn with pliers.
- Turn on the Water: Make sure the valve is fully closed and turn on the main water supply valve. Then check the compression fitting for leaks. Slowly open the shut-off valve and see if the compression fitting and flex tube fitting are watertight. If any water appears, tighten the nut a little further. Check for leaks over the next few hours as slow leaks can develop; if so, continue tightening the nut.
A cautionary note is that compression valves can potentially blow off under extreme pressure. A plumber will typically use a soldered valve, but installing one is a bit more complicated. Therefore, you may need a professional’s help.
Contact Sky Heating & Air Conditioning
Our licensed technicians specialize in all types of plumbing repairs. Homeowners in Portland and The Dalles can trust us to fix leaky pipes and other issues. If you have questions about how to replace a compression shut-off valve, Sky can help. To request plumbing services, including valve installation or piping and repiping, call 503-673-9083 today.