New Dishwasher That Will Not Drain After a Disposal Installation
A six-week-old dishwasher was installed by the homeowner's handyman at the same time as a new garbage disposal. The complaint is standing cloudy water in the sump after every cycle, dishes that feel gritty, and an occasional leak at the lower-left corner of the door during wash. There is no error code. The drain hose runs from the dishwasher up to the disposal, but it sags below the cabinet floor and has no high loop or air gap. When you disconnect the drain hose at the disposal inlet, you find the disposal's knock-out plug still in place. The dishwasher inlet screen is clean, and the float switch moves freely. The customer wants the dishwasher replaced under warranty and does not want to pay for a second installation.
1. Explain the diagnosis. Which symptoms are caused by which installation defect?
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The knock-out plug still in the disposal inlet blocks the dishwasher drain hose. The drain pump cannot discharge, so water stands in the sump and the machine may overfill during the next fill, leading to the door leak at the lower left. The sagging hose and missing high loop are separate installation defects: without a high loop or air gap, dirty sink water can siphon back into the dishwasher, which explains the cloudy water and gritty dishes. The absence of an error code does not mean the dishwasher is healthy; some models do not flag a blocked drain until the overflow switch trips. The float switch is free, and the inlet screen is clean, so the symptoms point to installation, not a failed pump.
2. What correction is required, and how would you prove it worked?
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Correct the installation. Remove the disposal knock-out plug and remove all plastic debris from the disposal. Route the drain hose with a high loop as high as possible under the counter, or install an air gap if the code or manufacturer requires it; avoid a sag. Secure the hose and check that it does not kink. Run a cycle and verify draining, no standing water, no door leak, and no backflow. Check the disposal for leaks at the hose connection. Prove the repair with a full wash and drain cycle, not just a visual check.
3. How would you handle the customer's warranty demand and document the visit?
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Explain that the dishwasher is not defective; the disposal plug was left in and the drain hose was not installed with a high loop. Warranty generally does not cover installation errors by a third party. Offer to correct the installation and document the findings with photos and a written report. Advise the customer to contact the handyman or installer about the cost. Do not submit a false warranty claim for a dishwasher replacement. Record the as-found condition, the knock-out plug, the hose routing, the correction, and the customer's response.