Step 7 · Tighten the Compression Fitting

This is the step most people slow down on. Take it one move at a time — there’s no rush, and you can rewind the clip as many times as you need.

Slide the compression nut up to the threads on the valve body and hand-tighten it as much as you can. Now, use your two wrenches again. Use one wrench as a backup to hold the valve body steady, preventing it from turning. Use the other wrench to tighten the compression nut an additional one-half to three-quarters of a turn. The goal is to compress the ferrule onto the pipe to create a seal, but not to overtighten it. Do not use plumber's tape or pipe dope on compression fittings.