About 7 years ago some brain dead loser installed a furnace in my house and just about burnt it down. I rewired it after the electrical fire....anyways,<br />I have been having to snug the line connections about every year or so 'cause they would start sweating.... I finally undid the one nearest the burner and cut the line and reflared... Looking at the piece i cut off, i see a double flare... and of course being copper, the rolled-in part is all split and it's no wonder it was leaking....<br />So, I assume single flare is proper... Double flare is for steel brake lines right?<br /><br />I guess I need to go redo all the other connections... they are 45 degree SAE flare
Don't forget to put the nut on first. (Like that will help.