Place the pliers around the square nut that protrudes from the top of the cap on the back of the P-trap. Turn the cap counterclockwise to remove it, exposing the top of the T-pipe on the back of the trap.
Wrap the pipe threads on the base of the automatic air valve with two layers of plumber's tape. This will help lubricate and seal the connection between the air vent and the P-trap.
Place the air valve into the top of the T-pipe on the back of the P-trap and screw it in by hand until tight.
Turn on the water and make sure the liquid drains properly. You should hear a slight rushing of air from the automatic air vent while the water is draining.
Things You Will Need
- Air admittance valve (automatic air vent)
- Plumber's tape
- Check your local plumbing codes to see whether automatic air valves are allowed for you specific application.