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Why is My Dishwasher Not Draining?

yury, 08/01/2016

Dishwashers are a useful part of any modern kitchen. Unfortunately, they’re not impervious to issues. One of the most common problems that occur with these appliances is water failing to drain. When this occurs, water pools at the bottom of the dishwasher and can lead to smells and further issues if not resolved.

Newer dishwasher models automatically stop the cleaning cycle to prevent leaking. Some even display a code to give owners a better understanding of the issue. Before you go out and call a repairman, try these steps to solve the problem yourself. Most drainage issues are easy to spot and fix in just a matter of minutes.

Examination Prep

Before you do anything, it’s always good to be safe. You should cut power to the dishwasher before you start digging for clogs. This can be achieved by unplugging the unit or switching off the circuit breaker. After that, remove the dishes and bottom basket from the unit. Clogs are commonly found in the bottom sump and filter, so you’ll need easy access to the area.

Remove and Clean the Filters

The first place to check for a clog is the lower filters near the sump. This is the lowest point in the dishwater where water collects and drains from the unit. A pump removes water and debris from this point and out through the drainage hose. It’s usually located beneath the lower spray arm or towards the back of the unit. Depending on the particular model of dishwater, you may have various filter components to go through.

Most dishwashers have two filter layers. One is a fine mesh designed to catch smaller food particles while the other is a large basket that prevents larger pieces from going through. Check these filters for residue. They can be removed with a simple counter-clockwise twist, though some models have screws holding the filters in place. Clean the filters in warm soapy water. If the filters are greasy, run them under very hot water and wipe away the grime.

Clean Out the Sump

In some cases, food debris can get past both filters and make their way into the sump. Before putting the filters back, take a look into the sump and clear out any blockages with a pipe cleaner or flexible wire. Give the impeller a look as well. This impeller turns to drive water out of the dishwater. It’s not uncommon for pieces of tough food or broken dishes to prevent it from turning.

Clear the Drain Hose

If the problem persists, the issue might be located in the drain pump. It’s not uncommon for fat and grease to solidify on its journey from the dishwasher to the drain. This gunk will build up over time and eventually block any water from going through. If you have an older dishwasher, corrosion may have caused a block. Either way, you’ll have to clear this clog manually.

To access the drain hose, remove the bottom front panel of the dishwasher. Manufacturers will use small screws or plastic clips to hold the panel in place. Once removed, find the drainage hose. It’s often the flexible tube that’s connected via a simple wire clamp. Before disconnecting it, straighten it out and feel for large masses. Sometimes, these clumps only need a bit of force to dislodge.

If that doesn’t work, disconnect it from the dishwasher by loosening the clamp and use a wire snake to remove any clogs. One method to check to if the hose is clear is to blow into one end. If you can blow freely, there’s still a significant block in the hose.

Check the Air Gap

In many installations, the dishwasher drain hose is connected to the air gap to prevent backflow. The air gap is usually located on the top of the sink and is covered by a simple cap. This gap can accumulate debris over time. Because it’s not an area that’s frequently checked, it can become clogged without realizing it. To clean the air gap, remove the cover. Most covers are shaped like a some and can be screwed off or lifted.

There should be a plastic cap below this that needs to be removed. Once this is removed, you should have access to the air gap. Use a towel and pipe cleaners to rid the gap of any accumulated debris. It’s also recommended to use air to dislodge stubborn debris and achieve a thorough clean. This can be done with an air compressor or by simply blowing through a cardboard tube.

Free the Float Assembly

Located on the bottom of the dishwasher, the float assembly plays a pivotal role in the filling and draining of the unit. Essentially, the float triggers a switch to start and stop the filling and draining cycles. If debris gets in the float’s path, it can prevent the unit from draining properly.

The first step is to remove the cap of the assembly. Depending on the model, it may snap off or require a screwdriver to remove. Once off, check to see if the assembly can move freely. Simply lift it up and let it drop. It should be able to move without any obstructions. Drainage problems occur if the float assembly snags on debris and is unable to drop all the way down. If there’s debris, clean it out thoroughly and replace the assembly.