I put a new water valve in the refrigerator,Now when i put back the copper
supply it has a small leak at the fitting.
I cut the fitting off & installed a new compression ferrule & it still leaks
no matter how tight i make it.
Does it need teflon tape on the threads,it didn't have any before i changed
How can i fix the leak ?
Nope, you don't use teflon tape on compression fittings. The threads
are not sealing, the compression ring is. Teflon tape is only used on
tapered pipe thread.
Are you sure it is the compression fitting and not the nearby valve
stem? I've seen a lot of these that leak at the valve stem after they
have sat for years without being touched and then someone tunrs them
off. Make sure the valve stem is all the way open and snug.
If it is the compression fitting all I can suggest is trying again.
Make sure everything is clean and the copper line is straight in the
fitting and fully in as you tighten.
A couple things to try:
1) Spray the nut, ferrule, and end of the tube with oil
before tightening. This allows the surfaces to slip instead
2) snug, not "as tight as you can get". The ferrules deform
I know of a plumber who uses Rectorseal #5 on compression
fittings, but I've not had to do that.
Pipe dope is not a sealer it's a thread lube to allow steel/cast
fittings to be tightened without thread bind. I've NEVER had problems
with ferruled connections leaking when they were done carefully.
Another poster going by Jimmie pretty much explained how to make
successfully and lasting compression joints.
Pipe dope is a sealer also. It's made for pipe threads, not compression
fittings, but still it is a sealer.
Note the product information "Lubricates and seals all threaded joints"
No, it hasn't. Maybe it *appeared* to work, because there wasn't enough
pressure behind the leak to push the water past a massive glob of pipe dope,
but it's still not the right way to do it.
Pipe dope is not a sealant, and has no place on a compression ferrule.
If a compression fitting leaks, it's due to a poor fit. The proper solution is
to fix the problem causing the poor fit, not to cover it up with a blob of
It is also a sealant, not for compression fittings, but still it is a
"Lubricates and seals all threaded joints"
One of the most common mistakes with compression fittings is
tightening them too tight. Sometimes if you have trouble with the
brass ferrules you can try a plastic one. They seem to be a little
more forgiving. Make sure the pipe is clean with no rough spots. Don't
quite seat the pipe all the way against the stop. Google How to
install a compression fitting" think there is a video with some good
I cant always think of how to tell someone how to do something so I
went to my book. To keep from over tightening it. hand tighten the nut
and then tighten about 3/4 a turn with a wrench. Very important, use a
second wrench to hold the body of the fitting. Cu and nylon ferrules
work a little better than the brass ones because they are softer.
I wonder if the OP used the same nut and fitting from the previous
installation, while just buying a new ferrule. If the old fitting
had been tightened too much, there might have been damage or
deformation of the nut or seat.
On more than one occasion I've "saved" an dripping overtightened ferrule
fitting by putting a couple of wraps of teflon tape around the ferrule
lapping it onto the far end of the copper tubing by about 1/8".
The teflon compresses to form a "gasket" which seals the leak.
Scoff if you will, but I've always said that the essence of pragmatism
can be stated as, "If it woiks, use it." <G>
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