The dishwasher makes a loud banging or thumping noise during operation, especially at the start or drain cycle.

Safety First: Turn off power and water if adjusting plumbing.

Check installation:

• Verify the dishwasher is securely fastened to the countertop or side cabinets using its mounting brackets.
• Ensure the drain hose and supply line are not loose and banging against the cabinet; secure them with clamps or foam.

Water hammer:

• If banging coincides with valve opening/closing, consider installing a water hammer arrestor on the dishwasher supply line (consult a plumber if unsure).

Rack loading:

• Ensure tall items do not interfere with spray arm rotation.