There's a section of my supply line to my swamp cooler (1/4" copper) on the roof that had a small crack in it. So, I figured I'd just cut out that small piece and use a compression union fitting to connect it back together. I got the compression fitting from HD, in the section with all the swamp coolers and cut my line. However, the compression sleeve is too small to fit the copper tubing, and so is the threaded part of the fitting that the copper line is supposed to go into. It's not just a tight fit, either - there is no way it's going to go on.

Am I doing something stupid here, or is there something I'm not getting? I've used compression fittings before (on bigger pipe), so I know how they're supposed to work. I cut the tubing with a hacksaw and then cleaned up the ends, so I don't think I deformed the tubing significantly.

Thanks for any ideas.

The tubing size is probably 5/16", not 1/4".

is it a water line? if it froze and cracked then it most likely expanded just enough so the fittings won't go over it.
hj's trick is to use the squeezing side of an inexpensive flaring tool to clamp aroung the tubing and make the OD smaller.

Usually, tha means the tubing froze at some time and expanded. Sometimes you can use the "block" from a flaring tool and compress it back to size again, but usually, you have to remove the expanded part until you find a section that is the correct size to start over.

But you have to go a little bit at a time and rotate the tool 90 degrees each time.

Yeah, it just turned out that a bigger section expanded than I realized. I just replaced that whole section, and everything's good! Thanks for the input.



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