The basic compression fitting was normally used to connect faucets and toilets. It was also used for other water connections,
but never for and entire house. It can also be found on oil lines, although this is no longer considered safe and should be
replaces with flare fittings.
Due to the replacement of compression fittings for fixtures to braided lines(or flex supplies), these new supplies will
also be covered here, below the actual compression fitting.
The compression fitting uses a nut and a ring, known as a ferrule, to seal against leaks. The threads on compression fittings
are not tapered like that of iron pipe. As the nut is screwed on, it compresses the ferrule into the copper tubing.
The nut and then the ferrule gets put on the copper tubing first. Then the pipe gets inserted into the fitting.
Then the nut gets screwed together. Tightening a compression fitting can be tricky. If you don't tighten it enough, it
will leak and can even come apart. If you go too far, it can compress far enough that it can also leak. It is best to start
too loose and then tighten up a bit if there is a leak. About handtight plus 3/4 of a turn is a good starting point.
Thank you flex supplies!!!! Flex supplies have made the plumber's life much easier. The supplies come in the size for
faucets(left) and for toilets(right). The come in 9" 12" 20" 30" and sometimes even 48" lengths. They have also been developed
for dishwashers and for hot water heaters.
The small end of the toilet and faucet supplies are the same size as the nut for 1/4" compression. The other side fits the
fixture that you are working with. They do also make them with both sides 1/4" compression. The 1/4" is inside diameter. The
supplies generally are marked with the outside diameter, making them 3/8"od.
Flex supplies use a rubber seal inside them to prevent leaks.