Quick Connect Fitting - Capillary Stuck

It's been over tightened when installed. If you cannot remove via pliers and it's stuck in a LC column, you can try placing the capillary end in a vice (cranked up with hard jaws) with a small gap between the jaws and column end nut, and then use a flat bladed screwdriver inbetween the column end/vice jaw to get more leverage than pulling with pliers. Staff need to be trained, install a capillary finger tight and then an 1/8th of a turn, if the ftting still leaks add only another 1/8th of a turn.