Brass Compression Fittings

It is important to the integrity of a compression fitting that excessive force be avoided when tightening the nut. If the nut is over tightened, the ferrule frequently deforms improperly causing the joint to fail. Indeed, over tightening is the most common cause of leaks in compression fittings. A good rule of thumb is to tighten the nut first by hand until it is too difficult to continue and then tighten the nut a half-turn more with the aid of a wrench; the actual amount varies with the size of the fitting, as a larger one requires less tightening. The fitting is then tested: If slight weeping is observed, the fitting is slowly tightened until the weeping stops.