Samsung Dishwasher Keeps Draining

Introduction

Occasionally, your Samsung dishwasher will continuously (or nearly so) run its drain pump. There are a few causes for this problem. Let’s walk through the solutions. Commonly, the drain pump is run for 20 seconds and then is off for 5 seconds.

The Basics

A few things to check before digging in. These assume that the drain pump is running nearly continuously or that the machine cannot fill and run a cycle because it drains as soon as it is filled or possibly before it is fully filled.

Are there any error or fault codes displayed?

The two most common that will be associated with this condition are Overflow or Overfill Errors and Leak Detection faults. You may also see Drain Error Codes as well.
If you have a code, go to Error Codes below. Then, run through the rest of the questions.

Is the dishwasher emptied of water when you check inside after the pump runs for a few minutes? Does it stop and then restart shortly afterward, or just run continuously?

This suggests a leak detection issue, which will trigger an ongoing pump-out. This action overrides any cycle; you can shut the power off to the unit, and when it is turned on again, the pump will run if moisture is detected. Here is a page that gives you some solutions to this condition.

Is there standing water in the bottom of the dishwasher after the pump runs for a few minutes?

This suggests an issue with the pump or a clog in the drain. You will likely encounter an error code as well. Here is a link to a page to deal with this kind of problem.
This may also occur when the water supply valve is failing and allows water to enter the dishwasher after the pump shuts down. If the machine fille enough, the pump will start again, or it may start and run continuous pump out cycles.

Is the dishwasher filling and then draining almost immediately?

This suggests a problem with the water level system, likely leading to an overflow error, which will trigger a pump-out. Take a look at Flow Meter Problem below.

Here is a list of some error codes you might encounter:

Digital display codes

OC or oE — Overflow error

LC or LE — Leak detected

5C or 5E or SC or SE — Drain Error

Blink or Flash codes

Blinking Heavy button on models without Express 60 — Leak Detected,

Blinking Heavy with Express 60 — Overflow Error

Blinking Heavy with Smart Auto — Overflow Error

Blinking Auto with Heavy — Overflow Error

Blinking Smart Auto Light — Water Supply Error

Blinking Quick button — Long Drain Error

Now we take a look at the causes!

Causes

Failed Inlet Valve

A failed inlet valve will not stop filling the dishwasher. Leakage from this valve will result in an overflow error. There are a couple of failure modes.

Valves need 20 psi minimum to shut properly and they won’t necessarily stay shut if the pressure exceeds 120 psi. If your pressure is this high, you will likely notice it at household faucets and increased water hammer. Low water pressure will also be noticed in the same way.

The second is debris in the valve which prevents it from closing. If the valve has problems with this, don’t try to repair it, replace it.

Water Level Sensing System Problem

There are three sub-causes for water level sensing problems.

A stuck float will cause an overflow error (the flow meter paddles turn, but the float never moves to signal a full condition). The dishwasher will allow filling for a short time but then stops filling and runs the drain pump. Usually 20 secoinds on and 5 seconds off. This is often caused by mold growing in or debris that enters the water-level float chamber. You can try cleaning the chamber. On some models, it can be detached from the case break assembly, so you only have to replace the float chamber.

The water level float chamber is connected to the tub by a hose that may become clogged with debris. This will cause an overflow error and result in the pump-out cycle. You can often blow out the obstruction with compressed air or blow into the hose (kind of nasty). The obstruction (if present) will end up in the dishwasher’s sump, so be sure to remove it if you dislodge it.

The flow meter paddles may not turn. This is usually not the case, but if the float moves and signals a full condition, and the flow meter is jammed or turns slowly, you will get an overflow error. You will also get an overflow error if the water inlet valve is opened but the paddle wheel doesn’t rotate. This usually requires replacing the case break assembly as the flowmeter is built into it.

Control Board Failure

This is a much less likely mode of failure in this situation. You should consider replacing the main control board only after all other causes are eliminated. You may even have to replace some other parts, like the case break assembly, as there are no easy means for a DIY fixer to test items like the flow meter.