Newly installed AmazonCommercial disposal runs but dishwasher water backs up into sink or leaks from dishwasher inlet; some models may indicate five flashes on internal LED when sensing backflow.

Safety First: Turn OFF power to the disposal and dishwasher. Do not run either appliance while hoses are disconnected.

• Step 1 – Check if the knockout plug was removed: On new AmazonCommercial disposals, the dishwasher inlet on the side comes sealed with a plastic knockout. Disconnect the dishwasher drain hose and look inside the inlet; if you see solid plastic, the plug is still in place.
• Step 2 – Remove the knockout plug (if present): Insert a flat screwdriver into the inlet and tap gently with a hammer to knock the plug into the grinding chamber. Retrieve the loose plug from inside the chamber with tongs.
• Step 3 – Clean and reconnect the hose: Ensure the dishwasher inlet nipple is clear. Slide the hose fully onto the nipple and secure it with a stainless-steel hose clamp.
• Step 4 – Check hose routing: Ensure the dishwasher drain hose has a high loop or air gap above the sink level to prevent backflow.
• Step 5 – Test: Run the dishwasher drain cycle and observe for leaks or backup.