If your dishwasher is cleaning poorly, check these:
Most cleaning problems are caused by the dishwasher not getting enough wash water, so the water-inlet valve is often to blame. This valve is usually at the bottom left or right of the dishwasher, behind the lower access panel. It's the device with the main water line from the house, a rubber tube to the dishwasher, and two wires attached to it.
When a water-inlet valve is defective, you may hear the sound that's usually referred to as "water hammer." If the water-inlet valve is defective, you need to completely replace it.
Every dishwasher has some type of filter to keep large food particles and foreign objects away from the pump assembly:
- Most modern dishwashers have self-cleaning filters that don't need any routine cleaning.
- Some have filters in the bottom of the dishwasher that you need to periodically clean. You don't need any tools to remove the filter, and cleaning it is easy. Consult your owner's manual to determine which type you have and its maintenance requirements.
If your filter is clogged, it may be causing the cleaning problem.
Some dishwashers have a valve (or gate) that should open only during draining. If debris lodges in the valve, it can't close properly, so water drains out during the wash cycle. Most dishwashers drain into the garbage disposer. If yours does that, listen for water flowing into the disposer during the wash cycle. If you can hear it then, the drain valve may be clogged.
There's a spray arm at the bottom of your dishwasher--it may have a tall spray tube mounted to the center of it. There may also be a spray arm located directly beneath the upper rack of dishes and/or above the upper rack.
If debris is blocking the holes in the spray arms where the water comes out, it could cause cleaning problems. Regularly inspect each of the spray arms and clean out the holes as necessary.
To get the best cleaning results, the water entering your dishwasher needs to be hot enough. Try running the hot water in your kitchen sink for about 30 seconds before starting the dishwasher, to pre-heat it. Also, if your dishwasher lets you select a higher wash or rinse temperature, try that to see if it helps.
To check the temperature of the hot water that comes from your kitchen faucet use a waterproof thermometer. If the water isn't 120 degrees Fahrenheit, your dishwasher may have trouble getting your dishes clean. You could increase the temperature of the hot water to the whole house--and therefore the dishwasher--by adjusting the hot water heater thermostat.
Warning! To lessen the risk of scalding, don't set the hot water heater temperature higher than 120 degrees Fahrenheit.
Dishwashers don't perform their best if detergent is introduced only at the beginning of a cycle, so add detergent to both parts of the cup.
If the detergent cup isn't opening, see the "The detergent cup doesn't open" section, below.
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