Step 6 · Tighten New Valve Connection
With the new valve hand-tight, use the two-wrench technique again. Hold the valve body stationary with one adjustable wrench. With the second wrench, tighten the compression nut clockwise. A good rule is to tighten it one full turn past hand-tight. You will feel the ferrule bite into the copper pipe. Do not overtighten. The connection should be snug and secure, not excessively forced.