How to Diagnose Filling and Dispenser Problems in a Dishwasher

If you have filling or dispenser issues with your dishwasher it will not perform to its full ability. Find out how to diagnose and repair such faults by watching this eSpares video.

• Multimeter (digital or analogue)
• Screwdriver

We’ll now run through some of the main reasons as to what could be causing the problem to your dishwasher, and how you yourself can actually identify the potential cause.

Switch Off Your Appliance

Safety First! Please make sure that you have switched your appliance off at the mains before starting your repair.

My Dishwasher Isn’t Filling With Water

Well, there can actually be a few reasons as to why this problem might occur.

You can initially start by checking the supply hose, and if you find that it has been twisted or blocked in any way then you can fix the issue. On the other hand, It may be that the fault lies in the dishwasher - or it could be a problem with the water supply itself.

To find out if it is a problem with the water supply, a good way to check is to turn the supply off at the tap and then disconnect the inlet hose from the back of the dishwasher. If you then grab a bucket and turn the supply back on, then try to fill the bucket with water from the hose.

If the flow of water is quite fast, or if it's what you would normally expect to be coming from your tap, then that would indicate that the supply is ok and that the problem lies in the dishwasher. If this is the case then the next place to have a look at is the solenoid valve at the back.

To get to the solenoid valve you will need to remove the side panel. You can now use a multimeter to test the valve itself as to whether it's working or not.

Start by removing the connections from the valve, and then grab your multimeter - putting it onto a medium to high resistance setting - before placing the probes of the meter onto the terminals of the valve.

For a working valve you're looking for a reading somewhere between 2,000 and 5,000 ohms, and on this one, I'm getting about 4,000 so that shows that it's OK. Obviously, if you get readings that are significantly outside those figures then you should replace the valve.

Once the water comes through the solenoid valve on some machines, it goes through a flow meter, and on this particular dishwasher it comes up through this hose, then through the air break (or heat exchanger) - then down through this hose into the sump at the bottom of the dishwasher.

The water is then on some models monitored by a pressure switch.

Now to show you the pressure switch we need to have a look at the other side of the dishwasher. The pressure switch is connected to the sump through a thin pipe.

As the water comes into the sump it forces air along the tube into the pressure switch - and the pressure switch then takes a reading of how much air is coming into it.

From this reading, it can determine how much water is in the sump, however, if a blockage forms in this pipe the air isn't going to be forced through it properly and the switch isn't going to take a proper reading.

As a result of this happening the dishwasher is going to overfill and flood with water. If that's what is happening with your dishwasher, just have a look at this pipe here.

If you suspect there might be a blockage you can actually just remove the pipe from the switch, and blow into it to clear any blockages that might be in there. Now, this dishwasher has an additional pressure switch here, and this monitors the flow of water from the wash pump.

If your dishwasher has two pressure switches, and you're in doubt as to which one is monitoring the sump, you can just blow into both to be sure.

The dispenser has two functions, one is to release the detergent and the other is to release rinse aid. A couple of minutes into the cycle the dispenser will open, making a very distinctive thumping noise as it releases the detergent.

Also during the final rinse cycle, you may hear a very slight buzzing noise as the rinse aid is released into the dishwasher.

Now if you don't hear either of those sounds or the detergent isn't being released from the dispenser, you can see how to replace the dispenser in another eSpares video.

Final Comment From eSpares:

We hope you have enjoyed watching this video and have been able to find it of some use when trying to identify the reason for the issue you are experiencing with your dishwasher. For all related spare parts, you can see the dishwasher area on the eSpares website. You can also view lots more helpful articles and videos in our Advice Centre.