Sunday, September 21, 2008

Dishwashers - Washability Problems


Water Temperature
The temperature of the incoming water is critical to the operation of a dishwasher. Most
dishwashers have heaters, and some have delay periods that extend the time during which
water is heated to a specified point, but this does not fully compensate for low temperature
of the water supply. You can check the temperature of hot water at the sink nearest to the
dishwasher with a thermometer. Open the hot water faucet. Let the water run until it is as hot
as possible, and then insert the thermometer into the stream of water. On some models, if the
thermometer reading is below 140 degrees Fahrenheit, you will have to raise the water heater
thermostat setting. On other models, the dishwasher was designed to operate with water
temperatures as low as 120 degrees Fahrenheit. These models have longer detergent wash
periods that allow 120-degree Fahrenheit supply water to be heated up to a temperature that
gives good washability results. The dishwasher delay periods occur in only one, two, or three
of the water fills, and do little for the remaining rinses. Except during delay periods, the water
is not in the dishwasher long enough to be heated adequately.

The Detergent
The kind and amount of dishwasher detergent that is used is an important part of getting
the dishes clean. Different brands of dishwasher detergent contain different amounts of
phosphorous, which works to soften water and prevent water spots. If the water is hard,
you will have to instruct the customer to use a detergent with a higher phosphorous
content—above 12 percent. If the water is soft, the customer can use a low-phosphorous
dishwasher detergent. Some areas restrict the phosphate content to 8 percent or less. This
means that the customer will have to increase the amount of detergent used in those areas
where the water is hard. This is done by adding 1 teaspoon of dishwasher detergent manually in the main wash cycle for each grain of water hardness above 12 grains (water hardness is measured in grains):
• 0 to 3 grains for soft water
• 4 to 9 grains for medium-hard water
• 10 to 15 grains for hard water
• Over 15 grains for very hard water.
If the hardness of the water supply is unknown, contact the local water department.
Always instruct the user to use automatic dishwasher detergent only. The use of soap,
hand dishwashing detergent, or laundry detergent will produce excessive suds and will
cause flooding and damage to the dishwasher.

Loading the Dishwasher
When loading the dishes into the dishwasher, make certain that you load the top and bottom racks according to the use and care instructions provided by the manufacturer. Overloading the dishwasher will provide poor washability and an unhappy consumer.

Step-by-Step Troubleshooting by Symptom Diagnosis

Poor Washability on the Upper Rack
1. Is the upper spray arm turning?
a. Are the holes in the spray arm plugged?
b. Check to see if the spray arm is split.
c. Is there uneven loading of the dishes?
d. Check the filter assembly for blockage.
e. Check the lower impeller to see if it is defective or blocked with debris.
f. Are any objects protruding down that might prevent the upper spray arm from
rotating?
2. Is the water charge okay?
3. What is the temperature of the water entering the tub? Is the temperature at 140 degrees Fahrenheit?
4. Is the user using the proper amount of detergent?
5. Is the detergent dispenser functioning properly?
6. Are the dishes loaded properly? Ask the user to load the dishwasher so that you can observe whether he or she is loading the dishwasher properly.
Poor Washability in the Lower Rack
1. Is the lower spray arm turning?
a. Are the holes in the spray arm plugged?
b. Check to see if the spray arm is split.
c. Is there uneven loading of the dishes?
d. Is the spray arm binding on the housing?
e. Are any objects protruding down that might prevent the lower spray arm from
rotating?
2. Is the water charge okay?
3. What is the temperature of the water entering the tub? Is the temperature at 140 degrees Fahrenheit?
4. Is the consumer using the proper amount of detergent?
5. Is the detergent dispenser functioning properly?
6. Are the dishes loaded properly? Ask the user to load the dishwasher so that you can observe whether he or she is loading the dishwasher properly.
Poor Drying
1. Is the water hot enough? Check the water supply temperature. On certain models,
check to see if the cycle extender is functioning properly.
2. Is the heater working?
a. Check the wiring.
b. Check the timer or the electronic control board.
c. Check for the correct voltage.
d. Check the heater itself.
e. Check the heater fan assembly.
3. Is a wetting agent being used?
4. Check the door baffle.
5. Check the vent system.
6. Suggest that the user open the door a little after the dry cycle has been completed.

Please send me your how-to questions (eric@erickleinert.com) and I'll answer them in this forum, helping you decide if you can fix your appliances yourself or if you need to call a professional.