If your dishwasher is not draining properly, or if your dishwasher won't drain at all, there are a few possible causes for the error. These causes can range from a simple blockage to a faulty part that needs replacing to get your dishwasher draining and working properly again. Whatever the problem, we're here to help. In this guide, we'll run you through how to diagnose draining and motor problems in a dishwasher so you can get your appliance back in action.
Throughout this guide, we'll be using a Gorenje dishwasher. The following checks and processes may differ slightly depending on the specific make and model of your dishwasher, but they should generally be the same.
What you will need
How to diagnose draining and motor problems in a dishwasher
Let's get stuck in! To learn how to diagnose dishwasher draining or motor problems, watch the video or read our step-by-step guide below.
Safety first
Remember, always make sure you switch your dishwasher off and unplug it from the wall before carrying out any work or maintenance.
Dishwasher not draining at all
Let's start with diagnosing a dishwasher that's not draining water at all. This is usually caused by a blockage in the drain pump, such as a piece of broken glass or some other foreign object. If you break a glass or similar item in the dishwasher, it's important to make sure you thoroughly remove all the glass to prevent such blockages. This includes checking and clearing the filter.
If a piece of glass has evaded your grasp and made its way to the drain pump, you will be able to identify this by the noise your dishwasher makes. About five seconds after you start running a dishwasher cycle, the drain pump will start making a low humming noise. This will be due to a piece of glass blocking the impeller from turning, resulting in the dishwasher pump not working properly. When this happens, you'll need to remove the blockage.
How to remove and check the drain pump
Before you start taking apart your dishwasher to access the blockage, first make sure you turn off the water supply and disconnect the inlet hose from the back of the dishwasher so you don't accidentally damage it.
Step 1: Remove the baseplate
Lay the dishwasher onto its back (not its side) to access the baseplate, making sure you don't trap or damage the drain hose as you do this. You will then need to remove the baseplate. Some dishwashers have a baseplate that can be removed by simply unscrewing the feet, but others will have a baseplate that is screwed into place by screws. To remove the baseplate, unscrew the screws with your screwdriver (if there are any) and also unscrew the feet.
Once you've fully unscrewed the baseplate, it will still be held into place from the inside by an anti-flood switch. To fully remove the baseplate, you will also need to unscrew the anti-flood switch as well.
Step 2: Remove the drain pump
You will now be able to see the drain pump inside your machine. You will need to remove the drain pump to check it, so start by removing the two electrical connections from the pump. We recommend taking a photo of these connections before removing them. You can then use that photo for guidance to make sure you reconnect the connections in the right places later.
As indicated below, there will also be a screw that you will need to remove in order to remove the drain pump. There may be a second screw on the other side that needs removing too.
You can then twist the drain pump and pull it off its chamber to remove it.
Step 3: Checking the drain pump
If there is any broken glass or debris blocking the drain pump, it will usually settle in the area around the impeller. If so, you can remove the blockages by hand, taking care not to cut yourself as you do so. You should use a kitchen towel or pair of safety gloves to keep your hands and fingers protected as you do this.
Once the impeller is clear of blockages, give the impeller a spin with your fingers to make sure it is turning properly again. The impeller may turn in a jerky motion, but this is normal due to how the magnet works.
Once you've checked the drain pump itself, you should also check the chamber that the pump screws onto to make sure there's nothing blocking the pump from there.
Finally, to be sure your drain pump is working properly, you can test it with a multimeter on the two terminals. Your multimeter should show a reading of about 200 ohms for a working drain pump. If you haven't used a multimeter before and aren't sure how, our quick guide on how to use a multimeter will tell you everything you need to know.
Step 4: Refit the drain pump
Once you're confident your drain pump is unblocked and working properly, you'll need to reconnect it. First, slot it back onto its chamber and screw it back into place.
Then reconnect the two electrical connections to the drain pump.
Check the drain outlet
If you've checked the drain pump for blockages and faults but the dishwasher's water is not draining still, there's another place you can check. Some dishwashers also have a flap that is fitted over the outlet that feeds into the drain hose. This flap opens and closes, but it can get stuck.
To check this, remove the drain hose from the drain pump. Then check that there are no blockages in the flap, and remove any you might find. You can also check that the rubber isn't tacky or sticky, thus hindering the flap's ability to open and close properly. If this is the case, you will need to either clean the flap or replace the drain pump.
Diagnosing a noisy pump
Moving on to noisy pumps, it's important to know that older drain pumps and wash pumps can develop a noisy squeal as they get older. This is usually caused by worn bearings, so if that's the case, you will need to replace the pump altogether. You can find our drain pump replacement guide linked at the end of the previous section.
Wash pumps are generally quite reliable, but they can get blocked just like drain pumps. When this happens, you'll need to remove the blockage from the wash pump.
If there isn't any sort of blockage, the capacitor attached to the motor can burn or develop a sort of bulge. Check around the terminals at the bottom for any burns or bulges to see if these are to blame. If the capacitor isn't damaged, you may simply need to replace the motor. You can learn how to do this with our dishwasher motor replacement guide.
Check the anti-flood sensor
Now let's take a look at the anti-flood switch. If you can hear your dishwasher constantly draining when you first put your dishwasher on, it may be because water has flooded and filled in the base, causing the polystyrene float to lift up and activate the anti-flood switch. If this happens, you'll need to drain any water out of the base and establish where the source of the flooding is coming from.
With all these checks carried out, you can reattach the baseplate by reconnecting the anti-flood switch and screwing the baseplate back onto the bottom of the dishwasher.
Fixing a dishwasher that's constantly draining
While some dishwashers can suffer from blockages and other errors that prevent draining, they can also suffer from constantly draining even when they aren't supposed to. There are two causes for this. The first is flooding in the base which triggers the anti-flood switch, as mentioned earlier. The second cause is when the end of the drain hose is set at a level lower than the water level in the dishwasher, creating a siphon effect.
The water level in your dishwasher should usually fill to just below the door seal, as indicated below. It's important to make sure the end of the drain hose isn't set to a level lower than this.
To fix this, simply reposition the drain hose to a level that's higher than the water level inside the dishwasher. Most drain hoses come supplied with a curved attachment called a drain hose u-bend bracket. You can use that attachment when setting the drain hose into the drain to make sure the hose doesn't slip too far down and create the siphon effect, as demonstrated below.
And there you have it! How to fix dishwasher draining problems and motor problems. Your appliance should now be draining and working properly once more!
While you're here, it's important to make sure you're using your dishwasher as efficiently as possible to prevent high energy usage and unnecessarily high energy bills. Our guide on dishwasher energy-saving tips will help you learn how to use your appliance in the most energy-efficient and cost-effective manner possible.
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