Bringing Opportunities to Developers in Spain. The compression coupling would have come with two nuts, one of which has been discarded as the supply hose has one built-in. An hour project of drilling and running flexible hose is well worth the pleasure of ice on demand. The seal on the copper tube is made by a ferrule that is located under the nut. I have no idea what the pressure is. Do you know what the pressure is? Be sure there are no burrs on the copper tubing after you cut it.
However, the best thing to do anytime you are connecting a line to either a faucet or refrigerator or whatever the case may be, before you put that last connection on the refrigerator, put that end in a big bucket and turn it on to clear the line of air and grub, because who knows how long it's been sitting.
Icemaker Water Lines