Drain Issues

There are a variety of drain issues, and we enter the realm of computer controlled appliances, zeroing in on the actual problem can be difficult. There is a lot of logic in the control systems that will spit out drain codes when there are no drain issues at hand. Point aside, we will discuss the basic drain functions of dishwashers here.

Drain Line

The drain line is the tube that connects the drain pump to the house plumbing supply. These drains use gravity in addition to the drain pump itself to expel water from the unit. Therefore, they need a high loop. This is where a portion of the tube rises above the top of the dishwasher.

• If the drain line is flat on the floor, the unit will fill with water, then will drain with water.
• As a matter of course, you should always ensure the drain line is proper.

Troubleshooting

Troubleshooting a dishwasher not draining is often a process of elimination. Activate the drain pump by cancelling a cycle. See if it turns on. Check for any error codes that might point toward a drain-related issue.

No Drain, No Drain Pump Noise

• Will need to check voltage to the drain pump.
  • If voltage present, but the pump is not kicking on, then you’ve got a bad drain pump.
  • If no voltage is present, then you’ll need to ensure the board is sending voltage, or if you’ve got a broken wire.

No Drain, Drain Pump Is Making A Noise

• If the drain pump is making a noise, this indicates it’s getting voltage. Might need to confirm it’s getting full voltage.
• Best to check for any obstructions in the drain line (such as debris build-up).
• Check for any debris stuck in the impeller, preventing it from spinning.
• If connected to a garbage disposer and the garbage disposer is new, ensure the knock-out has been removed.

No High Loop

Notice in this image how there is no high loop? When the drain pump kicks off, any water remaining in the tube will flow back into the dishwasher.

While this is not the worst configuration, it would be better suited with a high loop.

High Loop, and Congestion

Here’s a decent example of a high loop.

Also notice the debris: debris will get past the filters and will discharge and buildup in the line over time.

While the drain pump itself might be working perfectly fine, if there is congestion in the drain line, this will reduce the amount of water the drain pump can expel.

On newer units, you might see a drain code if the control system is checking current draw on the drain pump. Or you might see some water standing after the cycle is complete.