How to Replace a Dishwasher Air Gap

The dishwasher air gap is an important safety feature of your built-in dishwasher because it ensures that dishwater waste water travels into the sewage pipes instead of the fresh water supply. Follow the guidelines below to replace your dishwasher air gap in the drain hose.

Step 1 - Locate the Existing Air Gap

The air gap should be under a cover at the top of the cabinet above and beside the dishwasher.

Step 2 - Remove the Old Air Gap

Take the cap off the old air gap and loosen it by unscrewing the large circular plastic nut attachment that retains it in place.

Step 3 - Shut off the Circuit Breaker to the Dishwasher

Turn off the circuit breaker that supplies electricity to the dishwasher or disconnect the fuse in the fuse box.

Step 4 - Release the Dishwasher from Under-Counter Supports

With the screwdriver and correct sized head, unscrew the supports that hold the dishwasher under the countertop. You will need to open the dishwasher door to find these, as they are mounted inside the roof of the dishwasher.

Step 5 - Remove the Dishwasher from the Countertop

Pull the dishwasher slowly out from under the countertop, ensuring the electrical cable, water and drain hoses remain connected.

Step 6 - Find the Connection from the Drain Hose to the Air Gap

Trace along the drain hose with your fingers to find where it is attached to the air gap.

Step 7 - Pull the Air Gap Out

Pull the air gap unit down under the countertop to remove it.

Step 8 - Undo Compression Clamps

Use the screwdriver to release the compression clamps holding the hoses to the air gap inlet nozzle and outlet nozzle. Pull the hoses off the air gap unit.

Step 9 - Attach the New Air Gap to the Hoses

Fasten the new air gap's nozzles to the dishwasher outlet hose and to the dishwasher inlet or sink drain hose on the opposite sides. Place the hoses on the air gap on the same sides where you removed them from the old air gap. Attach and tighten the compression clamps with the screwdriver, so the hoses are secured but not crimped or cracked.

Step 10 - Refasten the Air Gap to the Countertop

Maneuver the air gap unit up through the countertop till it connects and aligns with the plastic retaining nut. Thread and tighten the retaining nut around the new air gap so it is in the correct position. Close the air gap cap.

Step 11 - Put the Dishwasher Back into the Counter

Slide the dishwasher back under the countertop so it aligns with the support screws. Refasten the support screws from inside the dishwasher, and restore the electricity to the dishwasher's power cable.

Step 12 - Test the New Air Gap

Load the dishwasher and run it through the shortest programmable cycle. Check for correct function of the air gap and for any water leakage. If there is water leakage from either the inlet or the outlet hose, adjust the compression clamps until the leakage stops. Be sure to turn off the electricity to the dishwasher while readjusting the compression clamps.