11-22-2010, 02:06 AM
It appears from this photo in your previous post that this is a compression fitting. If you have
never worked with them proceed with caution or you will be paying for a plumber to visit.
When you unscrew the nut on the bottom this is what you will see the copper line with a ferrule ring
Some folks will try to get by and use the existing ferrule but I don't think that it is a good idea.
The reason many like to reuse them is that they can be tough to remove if they or the copper line
is deformed, which is not uncommon. If you are patient you may be able to remove it by using
pliers or channel locks to work it off, but if the tube is deformed you will have to cut.
If you have to cut the tube and have never done this I would encourage you to go buy a length of
copper line and a small tube cutter and practice. For a tight space as you have under the sink I would
use a small cuter designed for tight spaces like this one.
The trick is to cut the tube and not deform it. If you deform it the compression fitting will leak - guaranteed
Once you get the hand of cutting the tube and feel confident, cut the existing lines and install the new valve.
The tricky part of installing compression fittings is getting the right amount of pressure on the fitting.
DO NOT OVER TIGHTEN - that's the most common mistake. If you do you can deform the end of the tube again
and have to cut them again. You don't have that much to spare. I usually snug them up and then turn the water
back on (prepared for leaking) If they leak I snug them up until they quit.
