| HOME | Troubleshooting | DIY Tips |
|
When a dishwasher is properly used, it will provide the customer with satisfactory results. There are times, however, when the dishwasher is blamed for poor performance. Perhaps the customer does not know how to load the dishwasher properly, or they used the wrong amount of detergent, and in some cases the dishwasher might not run at all. Whatever the case might be, it is up to the technician to repair the dish washer, or to instruct the owner in its proper usage. This section provides the technician with the basic skills needed to diagnose and repair automatic dishwashers. PRINCIPLES OF OPERATION After placing the dishes properly in the dishwasher, the detergent is placed in the dispenser, and the rinse conditioner is checked for the proper level. The door is closed, and the type of wash cycle is selected. The door latch holds the door closed and activates the door latch switch. This will complete the electrical circuit for the dishwasher to operate. If the door is opened during the cycle, this will cause all operations to cease. The timer will energize the water inlet valve. Water will begin to enter the tub. The dishwasher does not fill with water like a washing machine. It is designed so that the tub does not have more than two gallons of water in it at any one time. Should the timer switch contacts fail to open during the fill cycle, a float switch assembly, located inside the tub, will open the electrical circuit to the water inlet valve at a preset level. The fill safety switch is part of the float assembly. Should the timer fail to open its switch contacts, water will keep entering the tub until the float, located inside the tub, rises and engages the float switch to shut off the water. Note: The float switch will not protect against a mechanical failure of the water inlet valve. 1. During the wash and rinse portion of a cycle, the heater element heats the water (on some models) to at least 140 degrees Fahrenheit. This feature is built into the dishwasher, and it is designed to save the consumer money in the operating costs of washing the dishes. Also, the customer does not have to raise the water temperature of the water heater to 140 degrees Fahrenheit. They only need to set the water heater temperature at 120 degrees Fahrenheit. This will prevent any member of the household from getting burned. 2. The water is pumped through the lower and upper spray arms, and onto the dishes, over and over again. As the water runs off the dishes and back to the pump, it flows through a filtering system. On some models, the filter is designed to separate most food particles from the water so they won’t be sprayed back onto the dishes. At the end of a wash or rinse cycle, the water is pumped out of the dishwasher, flushing the filter of any small food particles. The larger pieces of food are trapped on the pump guard, which must be cleaned out before the next use. On some models, the pump screen removes food particles from the water, stores them, and then grinds up the food particles as they are washed down the drain. During grinding, some sounds will be heard. At the end of the cycle, the heater element comes on (if this is selected) and helps dry the dishes. Certain models have a fan that circulates the air to speed up the drying cycle, thus making sure that all dishes are evenly dry. Some models have a cool dry cycle. This cycle allows the dishes to be dried without the heater element operating. Combined with the heated air within the tub (from the wash cycle) and the dishwasher door opened a little bit, it will cause the water that remains on the dishes to condense and roll off the dishes. Figure __1 illustrates component locations within the automatic dishwasher. SAFETY FIRST Any person who cannot use basic tools, or follow written instructions, should not attempt to install, maintain or repair an automatic dishwasher. Any improper installation, preventive maintenance, or repairs could create a risk of personal injury or property damage. If you do not fully understand the installation, the preventive maintenance, or the repair procedures in this section, or if you doubt your ability to successfully complete the task on the automatic dishwasher, then please call your service manager. Before continuing, take a moment to refresh your memory of the safety procedures in Section 2. DISHWASHERS IN GENERAL Much of the troubleshooting information in this section covers the various types of dishwashers in general, rather than specific models in order to present a broad overview of service techniques. The pictures and illustrations that are used in this section are for demonstration purposes only; they clarify the description of how to service an appliance and they in no way reflect a particular brand’s reliability. Location and installation of a dishwasher Locate the dishwasher where there is easy access to existing drain, water and electrical lines (Fig. 2). Be sure to observe all local codes and ordinances for electrical and plumbing connections. It is strongly recommended that all electrical and plumbing work should be done by qualified personnel. The best location for the dish washer is on either side of the sink. For proper operating and appearance of the dishwasher, the cabinet opening should be square, and have dimensions as shown in Fig. 3. If the dishwasher is to be installed in a corner, there must be sufficient clearance to open the door (Fig. 4). __-1 Dishwasher component location. Upper dish rack; Timers; Door springs Take the time to read over the installation instructions, and the use and care manual, that comes with every new dishwasher. These booklets will provide you with very important information. Such as: • Safety • Tools needed for the installation • How to remove the panels • How to change the color of the panels Timer Float switch; Pump and motor • Locating drain, water, and electrical supply • Position, align, and level the dishwasher • Drain hose connection • Water line connection • Connecting the dishwasher to the electrical supply • Securing the dishwasher in the opening you have selected • Proper operation of the dishwasher • Most importantly, read the warranty information that is supplied with the dishwasher Functions and cycles Dishwashers are very similar to automatic clothes washers. They apply three kinds of energy on the things to be washed. These forces are: • Mechanical energy Water that is sprayed onto the dishes to remove the food particles. • Heat energy Using hot water to liquefy the fats and greases on dirty dishes. • Chemical energy Detergents to dissolve the fats and greases off the dishes. Dishwashers perform four basic functions that are modified and put together in different ways to create the various cycles. The four functions are: • Fill • Wash/rinse • Drain •Dry As with clothes washers, the only difference between the wash and rinse cycles is the presence of detergent in the wash water. The mechanical activities that make up a wash and a rinse cycle are basically the same function. Unlike clothes washers, most dishwashers fill and begin to wash (or rinse) at the same time. The functions are put together in various ways to make up different cycles. By example, some of those cycles are: • Normal wash cycle: A single or double wash, with several rinses and a dry. • Heavy wash cycle: Adds a wash to the normal wash cycle. • Pots and pans Similar to the heavy wash cycle, but this cycle heats the water in the wash cycles, and (on some models) this also heats the rinse cycles. On certain models, the timer will not advance until the water temperature is 140 degrees Fahrenheit. This will extend the total time of operation. Depending on the model, the cycle time can increase from 15 minutes to 2 hours. (Check the use and care manual) • Light wash cycle: This cycle is like the normal wash cycle, but minus a wash cycle. • Rinse and hold: Two rinses for holding dishes to wash later. 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 periods 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, then insert the thermometer into the stream of water. On some models, if the thermometer reading is below 140 degrees Fahrenheit, then you will have to raise the water heater thermostat setting. On other models, the dishwasher was designed to operate with tailpiece 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. Entry must be above trap __-2 Typical dishwasher installation for a left or right sink application. Dishwasher; Countertop __-4 Dishwasher; Dishwasher corner installation; Door; dimensions. Water temperature above 150 degrees F It is not recommended to have the water temperature above 150 degrees Fahrenheit in a domestic dishwasher; above this temperature, certain components in the dish washer might be adversely affected. __-3 Undercounter dishwasher cut-out dimensions. Water temperature at 150 degrees F Water temperature 150 degrees Fahrenheit is the ideal temperature for a mechanical dishwasher. Detergent action, and the dissolving of greases, are at the maximum at this temperature. Drying of most materials in the dishwasher will be very satisfactory. Water temperature at 140 degrees F Water temperature at 140 degrees Fahrenheit is the minimum temperature recommended by most dishwasher and detergent manufacturers. At this temperature, detergent is still quite active, and most fats are dissolved so that they can be emulsified in the water by the detergent, and washed down the drain. Drying will be fair to poor as water temperature in the last rinse is lowered toward 140 degrees Fahrenheit in some models. Some improvement in drying is possible if the user will add a liquid wetting agent to the dispenser. Water temperature between 130 and 140 degrees F Water temperature between 130 and 140 degrees Fahrenheit is outside of the range for best dishwasher operations, and users will have to exert special care if they are to obtain satisfactory results. The cleaning action of detergents, and the dissolving of fats, are gradually reduced as temperatures drop below 140 degrees Fahrenheit, so the dishes will probably have to be well rinsed before putting them into the dish washer. Satisfactory drying becomes less likely as water temperature becomes lower. Some dishwashers have an optional feature which will increase the temperature of the water in the tub at different points during the cycle. Water temperature between 120 and 130 degrees F Water temperatures between 120 and 130 degrees Fahrenheit will aggravate all of the conditions and problems mentioned for the 130- to 140-degree range. Very few fats will dissolve, so the greasy buildup in the lower areas of the tub will be accelerated. Sudsing and foaming is more likely to increase. Detergent action is further reduced, so pre-rinsing of the dishes becomes even more important. The water heat feature will most likely have to be used. Water temperature below 120 degrees F Because of poor washing, grease buildup, poor drying and foaming, it is most unlikely that the dishwasher will perform to the satisfaction of the user, if the water supply is at less than 120 degrees Fahrenheit. 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%. If the water is soft, the customer can use a low-phosphorous dishwasher detergent. Some areas restrict the phosphate content to 8%, or even 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. Dishwashers in general 111 • 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. STEP-BY-STEP TROUBLESHOOTING BY SYMPTOM DIAGNOSIS In the course of servicing an appliance, you might overlook the simple things that might be causing the problem. Step-by-step troubleshooting, by symptom diagnosis, is based upon diagnosing the malfunctions, with possible causes arranged into categories relating to the operation of the dishwasher. This section is intended only to serve as a checklist to aid in diagnosing a problem. Look at the symptom that best describes the problem that you are experiencing with the dishwasher, then proceed to correct the problem. Before testing any electrical component for continuity, disconnect the electrical supply to the appliance. No water to dishwasher 1. Is the water turned on? 2. Is there voltage to the water inlet valve solenoid? 3. Is the water inlet valve solenoid defective? Disconnect the electrical supply, and check the solenoid coil with an ohmmeter. 4. Is the water valve plunger stuck? Disassemble the water valve and check. 5. Is the water valve inlet screen blocked? Turn off the water supply and remove the water supply line to inspect the screen. 6. Is the water fill line that goes to the water valve kinked? Check visually. 7. Is the water siphoning out of the dishwasher while it is filling? Check the drain hose installation. Low water charge 1. Is there adequate water pressure to the water inlet valve? Pressure should be between 15 and 120 pounds per square inch. 2. is the volume adequate? Take a quart container and fill it at the tap. The water must fill the container in seven seconds or less. 3. Is the water valve inlet screen clean? Turn off the water supply and remove the water supply line to inspect the screen. 4. On portables, you will check the aerating snap adapter on the faucet. 5. Is the timer defective? Disconnect the electric supply and check the switch contacts for continuity. 6. Is the float switch improperly positioned? Is the switch defective? Disconnect the electric supply and check the switch contacts for continuity. 7. Is the water fill line that goes to the water valve kinked? Check visually. 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 lower impeller to see if it is defective, or blocked with debris. e. Are any objects protruding down which might prevent the upper spray arm from rotating? 2. is the water charge OK? 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 the user 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 which might prevent the lower spray arm from rotating? 2. is the water charge OK? 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 the user 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 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. Suggest to the user to open the door a little after the dry cycle has been completed. Water leaks at the front of the dishwasher 1. Is the spray arm turning? Is it split? Are any of the holes blocked with debris? If so, this can cause the water to spill out of the tub. 2. Is the tub gasket in place? Check the corners especially. Worn tub or corner gaskets will cause water to leak out of the corners. 3. Did you check the vent baffle gasket? 4. Check to see if the tub is not overcharged with water. Too much water will spill over the front tub flange. 5. Does the door close properly and tightly where the latch fits the strike? 6. On some models, are the gasket clips in place? These clips secure the gasket to the tub. 7. Is the dishwasher loaded properly? Ask the user to load the dishwasher so that you can observe whether the user is loading the dishwasher properly. 8. Check to see if the dishwasher is draining properly. Inspect the drain hose where it enters the drain. 9. Most importantly, is the dishwasher level? 10. Check the door for any cracks. 11. Check to see if the wetting agent dispenser is working properly. Too much wetting agent will cause sudsing. Also, check the gasket between the door and the dispenser. Water leaks at sides, top, or bottom of dishwasher 1. Check the side inlet tube on the side of the dishwasher. 2. Check to see if water is leaking out from the pump assembly. 3. Check the motor seals for water leakage. 4. Does the tub have a hole in it? Is the tub rusted out? 5. Check the nut on the water inlet port. Is it tight? 6. Are the heater element nuts tight? 7. Check to be sure that all screws are tight. (motor and pump assembly, upper rack screws, etc.) The dishwasher cycle will not advance (the lights will come on) 1. is there voltage to the timer motor? 2. Are the cams in the timer rotating? 3. Is the dishwasher wired correctly? 4. Check to see if the timer is jammed. 5. Check to see if the selector switch is defective. The dishwasher cycle will not advance other than at start 1. Is the thermostat functioning properly? This thermostat must be flush with the underside of the tub. 2. Check for correct timer settings. The detergent cup won’t open: 1. Is there voltage to the solenoid? 2. Is the detergent mechanism adjusted properly? 3. Check to see if there is any binding at any point. 4. Check to see if any dishes are blocking the detergent cup door from opening. The detergent cup won’t close 1. Check the detergent cup actuator and cams. 2. Check to see if there is any binding at any point. 3. Is the detergent mechanism adjusted properly? The main motor won’t operate 1. Check for continuity at the start and mn windings. 2. Is there voltage to the motor? 3. Is the motor jammed? Check for foreign debris in the pump assembly. 4. Check to see if there are any loose wiring terminals, or burned wires. 5. Check to see if the motor assembly is wired correctly. The motor runs but goes into overload 1. Check the relay. 2. Is there any binding? Check the pump assembly for broken pieces of glass. 3. Be sure you have the correct voltage and the correct polarity. 4. Check to see if the motor windings are shorted. Door liner hits side of tub in undercounter models 1. Check to see if the tub is square. 2. Check the installation, and correct as needed. Dishwasher won’t start 1. Is there voltage to the dishwasher? Check the plug, circuit breaker, or fuse box. Also, check the wires in the junction box, located behind the lower front panel. 2. Check the door switch for continuity of the switch contacts. 3. Check the selector switch for continuity of the switch contacts. 4. Check to see if the timer and selector switch has been wired correctly. 5. Check for any wires that might have come off the timer or switches. The dishwasher repeats the cycle 1. Check the timer contacts; they should be open in the off position. 2. Check to see if the timer motor wires are shorted. Wetting agent assembly leaks 1. Open the door assembly, and check for leaks in the holding tank. 2. Check the wetting agent assembly for proper operation. Water siphons out through the drain pipe while the dishwasher is trying to fill 1. Is the drain line properly installed? 2. Check the installation instructions for proper installation. COMMON WASHABILITY PROBLEMS If there are no mechanical problems with the dishwasher’s operation, and the com plaints are that the dishwasher will not clean the dishes properly, or that the glass ware is cloudy, etc., the next step will be to look at the best possible cause for the problem that the customer is experiencing with the dishwasher. Then, proceed to correct the problem. If necessary, instruct the user how to get better results from their dishwasher. Poorly cleaned dishes On occasion, there might be some food particles left on the dishes at the end of the cycle. Possible cause: Water temperature might be too low. Remember, the water temperature should be 140 - 150 degrees F as it enters the dishwasher tub. Solution: Check the water temperature at the closest faucet. Let the water from the hot water tap run before starting the dishwasher, in order to clear the water line of any cold water. Possible cause: Not enough detergent for the degree of water hardness, or for the amount of dirty dishes to be cleaned. Solution: Use one teaspoon of detergent for each grain of hardness, with three tea spoons of detergent as a minimum in soft water. The dishwasher will require extra detergent for greasy pans. Possible cause: The detergent was placed in the wrong side of the dispenser cup. Solution: Instruct the user how to fill the dispenser, and have the user reread the use and care manual so that the detergent is placed in the correct dispenser for the cycle that is selected. Possible causes: Improper loading of the dishes into the dishwasher. 1. Blocking the spray nozzle. If a large bowl or pot is placed over the center of the lower rack, blocking the spray nozzle washing action when the lower rack is pushed in. 2. Larger items that shield smaller items from the washing action. 3. Observe to see if there is a nesting of the bowls, or silverware, so that the water cannot reach all surfaces. 4. The spray arms are blocked from turning. For example, tall items or an item that fell through the racks. 5. If an item blocks the detergent dispenser from opening, not allowing the detergent to mix with the water. Solution: Instruct the user to reread the use and care manual for the proper instructions on how to load the dishes for proper cleaning. Possible cause: Improper filling of water in the tub. Water pressure must be between 15 and 120 pounds per square inch. After the fill has stopped, check the water level in the tub. On most models, it should be even with the heating element in the bottom of the dishwasher. Solution: If the water pressure is low, be sure that no other faucets are in use while the dishwasher is operating. Possible cause: Not enough hot water. Solution: Instruct the user to use the dishwasher when the hot water is not being used for laundry, baths, or showers. Possible cause: If the dishwasher detergent is old and caked, it will not dissolve completely. Solution: Instruct the customer to always purchase fresh detergent, and store the detergent in a dry place. Etching Etching occurs when the glass is pitted or eroded. It appears as a permanent film on the glass. The beginning stages of etching can be identified by an iridescent look, shades of blue, purple, brown, or pink when the glass if held at an angle to the light. In the advanced stages of etching, the glass surface appears frosted or cloudy. Possible cause: Certain types of glass will etch, in any dishwasher, with the combi nation of soft water, the alkalinity of dishwasher detergents, and heat. Solutions: There is no way to remove the filmy appearance caused by etching; the damage is permanent. There is no way to predict what glassware might be affected; it is not related to the cost or quality of the glass. To prevent etching from recurring: 1. Adjust the amount of detergent according to the water hardness. 2. Adjust the water temperature so that it enters the dishwasher at approximately 140 degrees F. 3. Recommend to the customer that the Energy Saver dry cycle be used. 4. Instruct the customer not to manually pre-rinse the dishes before loading them into the dishwasher. Discoloration Discoloration (red, black, or brown) of dishwasher interior or dishes Possible cause: If iron or manganese is in the water, the dishes and/or the interior of the dishwasher might turn a red, black, or brown color. Solution: A rust remover can be used to remove the discoloration from the dishwasher interior. With the dishwasher empty, turn to the rinse and hold cycle, and start the dishwasher. During the fill, open the door and add cup of rust remover to the water. Allow the dishwasher to complete the cycle. Then, start the dishwasher on the normal wash cycle, with detergent, but without the dishes. To eliminate this condition from returning, the customer might have to install special filters to filter out the iron and manganese. Use a rust remover, as mentioned above, according to the manufacturer’s recommendations, to remove the discoloration from the dishes and the glassware. Lime deposits on the dishwasher interior Possible cause: If there is a lot of calcium in the water, a lime film or deposit might eventually build up on the interior surfaces of the dishwasher. Solution: You can try one of the following methods: 1. Use a mild scouring powder and a damp cloth to clean away the lime deposit. 2. With the dishwasher empty, turn the timer to the rinse and hold cycle. During the fill portion, open the door and add A cup of white vinegar to the water. Let the dishwasher complete the remaining cycle. Do not use detergent. After the cycle is completed, run the dishwasher with a regular load. 3. Use a product that removes lime deposits. Follow the manufacturer’s directions. Suds or foam in dishwasher Possible causes: 1. Sudsing in the dishwasher is caused by protein foods (milk, eggs, etc.), and an insufficient amount of detergent. 2. The water in the dishwasher is not hot enough to activate the de-foaming agents in the dishwasher detergent. 3. The user has used a non-automatic dishwasher detergent. Solution: Increase the amount of detergent to reduce the sudsing. Dishwasher detergents contain defoaming agents to break down the suds in the dishwasher water. Check to be sure that the water temperature is between 140 and 150 degrees F. Only use detergents that are for automatic dishwashers. Darkened aluminum Possible cause: A combination of water, heat, and alkaline foods will darken or stain aluminum products. Solution: To remove this discoloration, instruct the customer to use an aluminum cleaner, and to clean the item by hand. Never allow undissolved dishwasher deter gent to come in direct contact with the metal. Avoid placing aluminum items in the lower rack, right in front of the detergent dispenser. Discoloration of copper Possible cause: Some copper items will discolor when washed by hand, as well as when washed in the dishwasher, because of the heat and detergent alkalinity. Solution: Instruct the customer to use a copper cleaner to restore the copper color. Cracking (crazing) of china Possible cause: Crazing is the appearance of tiny cracks that appear over the entire surface of the china. It can occur when porous earthenware, good china that is very old, or lower quality china, is exposed to heat and moisture. Solution: Once the glaze is cracked or crazed, the damage is permanent. This characteristic is inherent in some clayware; and this type of damage can occur during use, handwashing, or automatic dishwashing. Chipping of china and crystal Possible cause: Chipping usually occurs during normal use and handling, and simply might not be noticed until the dishes are removed from the dishwasher. When the dishes are loaded into the dishwasher according to the manufacturer’s instructions, there is nothing in the dishwasher that can chip the dishes. The dishes should only come in contact with the cushioned vinyl coated racks. Solution: Instruct the user to follow the manufacturer’s instructions, in the use and care manual, for loading the dishwasher properly. Metal marks on dishes and glassware Possible cause: If a metal item, especially aluminum, touches a dish in the dishwasher, a metal mark might result. This symptom appears as small black or gray marks, or streaks, on dishes or glasses. However, most metal marks occur during normal use, when the dishes come in contact with the flatware. Solution. Instruct the user to load the dishwasher carefully, in order to prevent metal items from touching other dishes. There are products on the market that will remove these marks. Have the user read over the use and care manual, or check with the manufacturer for this information. Staining of melamine dinnerware Possible cause: Melamine dinnerware stains from contact with coffee, tea, and some fruit juices. If the surface is worn, it will stain more readily. Solution: Some specialty products on the market are recommended for removing these stains. Instruct the customer to read over the use and care manual, or check with the manufacturer for this information. Melting or warping of plastic items Possible cause: Some plastic items cannot be exposed to the temperatures usually found in dishwashers without changing shape. Solution: Once the plastic item has distorted, it cannot be returned to its original shape. In order to minimize, or prevent, plastic items from warping or melting, instruct the user to do one of the following: 1. Choose the air dry cycle to dry the dishes. 2. Place the plastic items on the top rack. 3. Purchase and use plastic items that are labeled “dishwasher-proof”. Discoloration of silverplate Possible cause: When silverplate takes on a copper or bronze colored appearance, the silverplate has worn thin and the base metal is showing through. The combination of dishwasher detergent and the lack of hand toweling might result in discoloration of this base metal. Solution: This discoloration can usually be removed by polishing the item with a silver polish, or by soaking the item in vinegar for about 10 minutes. This is only a temporary solution, however. Only a re-plating with silver, by a jeweler, will correct the problem. Tarnishing of silverware (sterling or silverplate) Possible cause: Sulfur in the water supply might be the cause. This effect might be accelerated by the automatic dishwasher because of the higher water temperature, and because the usual hand drying with a towel has been eliminated. Solution: Because sulfur cannot be readily removed from the water supply, frequent polishing is the only answer. Possible cause: Silver will tarnish easily if it is left in contact with foods such as mayonnaise and eggs. Solution: If silverware has been in contact with such foods, instruct the user to rinse the item thoroughly as soon as possible. Bluish discoloration of stainless steel Possible cause: A bluish discoloration of some types of stainless steel is caused by heat and the alkalinity of the automatic dishwasher detergent. Solution: This discoloration can be removed by using a paste of baking soda and water, or a stainless steel cleaner. Corrosion or rusting of stainless steel Possible cause: When the protective oxide film on the surface of the steel is re moved, corrosion will take place as with ordinary steels. Certain foods will remove the oxide film. They are: table salt, vinegar, salad dressings, milk and milk products, fruits and juices, tomatoes and tomato products, and butter. However, if the stainless is washed, rinsed, and dried thoroughly, the oxygen of the air will heal the breaks in the oxide film and return the stainless property to the steel. But, if food is not washed off promptly, the air cannot heal the break, and corrosion will occur. Solution: There is no permanent solution. To minimize rusting, instruct the user to rinse or wash the flatware as soon as possible after use. DISHWASHER MAINTENANCE The dishwasher’s interior is normally self-cleaning. However, there are times when the customer will have to remove food particles or broken glass in the bottom of the tub. Inform the customer to clean the bottom edge of the dishwasher tub, which is sealed off by the gasket when the door is closed. Food and liquids drip onto this area when the dishwasher is loaded. The control panel should be cleaned with a soft damp cloth. Tell the customer not to use any abrasive powders or cleaning pads. Also, advise the customer to read the use and care manual for proper maintenance procedures on their brand of dishwasher. Dishwashers are designed to flush away all normal food soils that have been removed from the dishes. However, on occasion, certain foreign objects, such as fruit pits, bottle caps, etc., might collect in the openings of the pump, and these items should be removed periodically to avoid clogging the drain system. Also, on occasion, some of these foreign objects can get caught in the spray arm openings, and will have to be cleaned out. Check the racks carefully to see if there are any nicks or cuts in the vinyl. These nicks and cuts can be repaired. A liquid vinyl repair material is available through the manufacturer, or any appliance supply store. REPAIR PROCEDURE Each of the following repair procedures is a complete inspection and repair process for a single dishwasher component; containing the information you need to test a component that might be faulty, and to replace it, if necessary. Water valve The typical complaints associated with water valve (Fig. 5) failure are: 1. The dish washer will run, but no water will enter dishwasher. 2. The dishwasher will overfill, and leak onto the floor. 3. When the dishwasher is off, water still enters the tub. 4. The dishes are not clean, not enough water enters the tub. 1. Verify the complaint: Verify the complaint by operating the dishwasher through its cycles. Listen carefully, and you will hear if the water is entering the dishwasher. 2. Check for external factors: You must check for external factors not associated with the appliance. Is the appliance installed properly? Is the voltage supply correct for the dishwasher? 3. Disconnect the electricity: Before working on the dishwasher, disconnect the electricity. This can be done by pulling the plug out of the wall receptacle. __-5 A typical dishwasher water valve. Be sure that you only remove the dishwasher plug. Double check to ensure that the electrical supply has been disconnected before removing any service panels. Another way to disconnect the electricity is at the fuse panel, or the circuit breaker panel. Turn off the electricity. 4. Remove the bottom panel In order to gain access to the water valve, the bottom panel must be removed (Fig. 6). The bottom panel is held on with 2 or 4 screws, depending on the model. Remove the screws, and remove the panel. __-6 Removing the bottom panel. 5. Remove the wire leads In order to check the solenoid coil on the water valve, remove the wire leads that connect to the solenoid coil from the wire harness (Fig. 7). These are slide-on terminal connectors attached to the ends of the wire. Just pull them off. 6. Test the water valve Using the ohmmeter, set the range on R X 1000, and place the probes on the solenoid coil terminals (Fig. 8). The meter should read between 700- and 900-ohms resistance. If not, replace the water valve. If you determine that the water valve is good, but there is little water flow through the valve, inspect the inlet screen. If this screen is filled with debris, it must be cleaned out. To accomplish this, use a small flat blade screwdriver and pry out the screen (Fig. 9). Then, wash out the screen, being sure that all of the debris is removed. Reinstall the screen. Turn on the water supply. Plug in the dishwasher. Allow the water to enter the tub to check the flow rate of the water valve. The tub must be empty because this will allow you to check the flow rate properly. On a normal fill, the water line should be over the heating element within two minutes (Fig. 10). When you turn the dishwasher on and energize the water valve, but no water enters the dishwasher tub, then replace the water valve. If the water valve checks okay, then check the timer and the wiring harness. Bottom screws Adjustable toe-plate Inlet valve solenoid terminals Wire leads from water valve solenoid coil __-7 Removing the wire leads from the solenoid coil. Inlet valve solenoid terminals __-8 Connect meter probes to the water valve solenoid coil. Screen; Float __-10 Diagram indicates water level in dishwasher tub. __-9 Removing the water valve inlet screen. Be careful not to distort the screen. Under filled 7. Remove the water valve Before removing the water valve, turn off the water supply to the dishwasher. Then, disconnect the water supply line from the inlet end of the water valve, and remove the fill hose from the outlet side (Fig. il). Next, remove the screws that hold the water valve to the chassis of the dishwasher. To install the new water valve just reverse the disassembly procedure, and reassemble. Check for water leaks. If none are found, reinstall the bottom panel, and restore the electricity to the dishwasher. 8. Operate the dishwasher Set the timer and control settings to operate the dishwasher through its cycle. Motor and pump assembly The typical complaints associated with pump and motor failure are: 1. The water will not drain out of the dishwasher. 2. Poor washability of the dishes. 3. When the motor runs, there are loud noises. 4. The fuses or circuit breaker will trip when you start the dishwasher. 5. Water leaking from bottom of the dishwasher, or water leaking on the motor/pump assembly. 1. Verify the complaint Verify the complaint by operating the dishwasher through its cycles. Listen carefully, and you will hear if there are any unusual noises, or if the circuit breaker trips. 2. Check for external factors You must check for external factors not associated with the appliance. Is the appliance installed properly? Does the appliance have the correct voltage? 3. Disconnect the electricity Before working on the dishwasher, disconnect the electricity. This can be done by pulling the plug out of the wall receptacle. Be sure that you only remove the dishwasher plug. Or disconnect the electricity at the fuse panel or at the circuit breaker panel. Turn off the electricity. 4. Remove the bottom panel In order to gain access to the pump and motor assembly, the bottom panel must be removed (Fig. 6). The bottom panel is held on with 2 or 4 screws, depending upon the model. Remove the screws and remove the panel. __-11 Disconnect water supply line. 5. Disconnect the motor wire leads Disconnect the motor wire leads from wiring harness. Check the motor windings for continuity (Fig. 12). Check for resistance from the common wire lead to the run winding (Fig. 13). Then, check the resistance from the common wire lead to the drain winding, and the common wire lead to the wash winding (Fig. 14). To check for a grounded winding in the motor, take the ohmmeter probes and check from each motor wire lead terminal to the motor housing (Fig. 15). The ohmmeter will indicate continuity if the windings are grounded (Fig. 16). If the motor/pump assembly showed signs of water leaking, then, replace the motor/pump assembly as a complete unit. Most part manufacturers give a one year warranty on the motor/pump assembly. There is no advantage in tearing down the motor/pump assembly; to only replace 1 or 2 parts; and receiving only a partial warranty. Replacing the motor/pump assembly as a complete assembly will save you time and money in the long run. If the motor/pump assembly checks okay, then check the timer and the motor relay (if the model you are repairing has one); and check for a kinked or plugged drain line. __-12 Check the motor windings for continuity. 6. Remove motor and pump assembly: Remove the lower dishwasher rack from the dishwasher. As shown in Fig. 17, remove the wash tower and spray arm assembly. If there is a filter, remove it also. Remove the motor wiring leads from the wiring harness, then, remove the drain line from the pump assembly. Reach underneath the tub and rotate the four pump hold downs 90 degrees inward (Fig. 18). You are now ready to remove the motor/pump assembly. Lift the motor/pump assembly out from the inside of the tub (Fig. 19). Keep the work area dry to help prevent electrical shocks. __-13 Check from the common to the drain winding. Blue - run winding White - common Red - drain winding Black - wash winding Blue - run winding White - common Red - drain winding Black - wash winding __-14 Check from the common to the drain winding (A), and to the wash winding (B). __-15 Check for the grounded motor; Ohmmeter __-16 The grounded motor 7. Reinstall motor and pump assembly: To reinstall the motor/pump assembly, just reverse the order of step 6. Before restoring the electricity to the dishwasher, pour a gallon of water into the tub and check for leaks underneath the tub. Restore the electricity to the dishwasher, and run the dishwasher through a cycle. Check for leaks again. If no leaks are found, reinstall the bottom panel. __-17 Remove the wash tower and the spray arm assembly. The typical complaints associated with dishwasher timer failure are: 1. The cycle will not advance. 2. The dishwasher won’t run at all. 3. The dishwasher will not fill. 4. The dishwasher will not pump the water out. 1. Verify the complaint Verify the complaint by operating the dishwasher through its cycles. Before you change the timer, check the other components controlled by the timer. 2. Check for external factors You must check for external factors not associated with the appliance. Is the appliance installed properly? Does the appliance have the correct voltage? 3. Disconnect the electricity Before working on the dishwasher, disconnect the electricity. This can be done by pulling the plug out of the wall receptacle. Be sure that you only remove the dishwasher plug. Or disconnect the electricity at the fuse panel or circuit breaker panel. Turn off the electricity. 4. Remove the console to gain access Begin with removing the four screws from the console to access the timer (Fig. 20). Turn the timer knob counterclockwise to remove it from the timer shaft and slide the indicator dial off the shaft. Remove the console panel from the dishwasher. On some models, the latch handle knob will also have to be removed. 5. Test the timer Disconnect the timer motor wire leads from the timer assembly. Using the ohmmeter, set the range on R x 1000, and place the probes on the timer motor terminals (Fig. 21). The meter should indicate some resistance. If not, replace the timer. If the motor checks out, then check the door latch switch, cycle extender relay, and the float switch assembly. Dishwasher timer __-18 An exploded view of a dishwasher motor/pump assembly. 6. Remove the timer To remove the timer, remove the timer mounting screws (Fig. 2 2). Remove the wire lead terminals from the timer. Mark the wires as to their location on the timer. Some timers have a disconnect terminal block instead of individual wires, which makes it easier to remove the timer wires. 7. Install the new timer To install a new timer, just reverse the disassembly procedure, and reassemble. Reinstall the console panel, and restore the electricity to the dishwasher. Test the dishwasher operation.
__-19 Remove the motor/pump assembly. After removal, inspect the tub for rust. Remove screw __-20 Remove the screws to access the control panel. The dishwasher door is hard to close The typical complaints associated with dishwasher door being hard to close are: 1. The door is hard to close. 2. The door won’t latch. 3. The dishwasher won’t run. 1. Verify the complaint Verify the complaint by trying to close and latch the door. 2. Check for external factors You must check for external factors not associated with the appliance. Is the appliance installed properly? Be sure that the dishwasher door is not binding against the side cabinet. Console; Remove screw; Timer motor terminals __-22 Removing the timer __-21 Attach the meter probes and test for continuity. Timer mounting screws 3. Run the dishwasher By pushing on the door, you finally latch the door closed. Next, run the hot water closest to the dishwasher to flush out the supply line. Then, turn the timer to the normal wash cycle with heated dry, and let it run through the entire cycle. By doing this procedure, the gasket will soften enough to form itself to the tub, while it is compressed. This should make it easier to latch the door. If not, adjust the latch assembly. If it is still too hard to close, then replace the door gasket. 4. Replace the door gasket To remove the old gasket, remove the screws or clips that hold the old gasket in place (Fig. 23). On some models, the gasket is pressed into the inner door assembly. Remove the inner panel from the dishwasher, and pull off the gasket from the panel (Fig. 24). Soak the new gasket in warm water to make it more flexible. 5. Test a new gasket After you have installed the new door gasket, close the dishwasher door, and test to see if the door latches without pushing hard against it. 6. Check for water leaks Run the dishwasher through another cycle to check for water leaking out the door. Most models have a baffle, or tub, gasket. If the dishwasher that you’re working on has one, then check to make sure it is not defective. The tub gasket is located either on the tub, or behind the inner door panel. To remove Insert screwdriver blade under flange of clip; pry outward To replace Apply pressure to flange of clip; press into place __-23 Removing dishwasher door gasket Dishwasher heating element The typical complaints associated with the heating element are: 1. Dishes are still wet at the end of the cycle. 2. The dishwasher stalls in the middle of the cycle. 1. Verify the complaint Verify the complaint by operating the dishwasher starting at the dry cycle. 2. Check for external factors You must check for external factors not associated with the appliance. For example, check the energy saver switch. Is it set for heat dry? Is the appliance installed properly? Does the appliance have the correct voltage? 3. Disconnect the electricity Before working on the dishwasher, disconnect the electricity. This can be done by pulling the plug out of the wall receptacle. Be sure that you only remove the dishwasher plug. Or disconnect the electricity at the fuse panel, or the circuit breaker panel. Turn off the electricity. 4. Remove the bottom panel In order to gain access to the heater wire terminals, the bottom panel must be removed (Fig. 6). The bottom panel is held on with 2 or 4 screws, depending on the model. Remove the screws and remove the panel. 5. Test the heating element To test the heating element (Fig. 25), remove the wires from the heating element terminals (Fig. 26). These are slide on terminal connectors attached to the ends of the wire. Use the ohmmeter to check for continuity between the two element terminals (Fig. 27). If the meter indicates no continuity between the terminal ends, replace the heater. To check for a shorted heating element, take one end of the ohmmeter probe and touch the element terminal; then, with the other probe, touch the sheath (outer cover of element) (Fig. 28). If the meter indicates continuity, the element is shorted, and should be replaced. __-24 Pull off the gasket: Be careful not to damage the door liner __-25 The dishwasher heating element __-26 Remove the wire terminals from the heater element. 6. Remove the heating element: To remove the heating element (with the wires already removed from the heater terminals), unscrew the locknuts that hold the element in place. From inside the tub, remove the heating element (Fig. 29). 7. Install a new heating element To install a new element, just reverse the disassembly procedure and reassemble. Then, test the new element by repeating step 1. Sheath; Electrical insulation; Heating element __27 Set the meter on the ohm’s scale. Connect the probes to the heater terminals. __-28 To check for a shorted element, attach the meter probe to one terminal and attach the other probe to the sheath. Cycle selector switch The typical complaints associated with the cycle selector switch are: 1. Inability to select a different cycle. 2. The consumer inadvertently selected the wrong cycle. 1. Verify the complaint In Fig. 30, verify the complaint by trying to select different cycles. 2. Check for external factors You must check for external factors not associated with the appliance. For example, is there any physical damage to the component? __-30 Selecting a cycle. __-29 Removing the heater element. 3. Disconnect the electricity: Before working on the dishwasher, disconnect the electricity. This can be done by pulling the plug out of the wall receptacle. Be sure that you only remove the dishwasher plug. Or disconnect the electricity at the fuse panel or circuit breaker panel. Turn off the electricity. 4. Remove the control panel: To remove the control panel, remove the screws along the top inside edge of the door (Fig. 20). On some models, you might have to remove the door latch knob, in order to completely remove the control panel. 5. Test the cycle selector switch: To test the cycle selector switch, remove all wires from the switch. Just remember, you will have to identify the wires according to the wiring diagram, in order to reinstall them back onto the cycle selector switch properly. Take your ohmmeter, and check for continuity on the switch contacts; press that switch which coincides to the terminals that are being checked (Fig. 31). At this point, you have to use the wiring diagram to identify the switch contacts. 6. Remove the cycle selector switch: To remove the cycle selector switch, remove the screws that hold the component to the control panel (Fig. 32). 7. Reinstall the cycle selector switch To reinstall the cycle selector switch, just reverse the disassembly procedure, and reassemble. Remember, you will have to identify the wires according to the wiring diagram in order to reinstall them back onto the cycle selector switch properly. __-31 Testing the selector switch contacts. Dishwasher door switch Sometimes the dishwasher door switch malfunctions and the door will not close properly. 1. Verify the complaint In Fig. 33, verify the complaint by closing the dishwasher door, and turning the timer dial to start the wash cycle. 2. Check for external factors You must check for external factors not associated with the appliance. Is the appliance installed properly? Does the appliance have the correct voltage? Is there any physical damage to the component? 3. Disconnect the electricity Before working on the dishwasher, disconnect the electricity. This can be done by pulling the plug out of the wall receptacle. Be sure that you only remove the dishwasher plug. Or disconnect the electricity at the fuse panel or circuit breaker panel. Turn off the electricity. 4. Remove the control panel To remove the control panel, remove the screws along the top inside edge of the door (Fig. 20). On some models, you might have to remove the door latch knob in order to completely remove the control panel. 5. Test the door switch To test the door switch, remove the two wires from the switch (Fig. 34). Close and latch the door. With your ohmmeter, check for continuity between the two terminals on the switch. Then, open the door latch and check for no continuity between the terminals. If the switch fails these tests, replace the switch. __-32 Removing the selector switch. __-33 Closing the door and running the dishwasher Closed position __-34 The dishwasher latch assembly in closed position. 6. Remove the door switch Remove the screws that secure the switch in place. Remove the switch. 7. Install new door switch To install the new door switch, just reverse the disassembly procedure, and reassemble. Then, reconnect the electricity, and test the dishwasher. Float and float switch Sometimes the dishwasher float and the float switch malfunctions and water will not enter the tub, or water overfills and spills onto the floor. 1. Verify the complaint Verify the complaint by closing the dishwasher door, and turning the timer dial to start the wash cycle. 2. Check for external factors -- You must check for external factors not associated with the appliance, as was done in the previous sections. 3. Disconnect the electricity Before working on the dishwasher, disconnect the electricity. This can be done by pulling the plug out of the wall receptacle. Be sure that you only remove the dishwasher plug. Or disconnect the electricity at the fuse panel, or the circuit breaker panel. Turn off the electricity. 4. Check the float Check the float from the inside of the tub (Fig. 35). Be sure that the float moves freely up and down. If there is any soap build-up around the float, clean it off. __-35. Inspecting the float assembly. Check for soap build-up around the stem and inside of the float 5. Remove the bottom panel In order to gain access to the float switch terminals, the bottom panel must be removed (Fig. 6). The bottom panel is held on with 2 or 4 screws, depending on the model. Remove the screws, and remove the panel. 6. Test the float switch The float switch is located under the float, and underneath the tub (Fig. 36). Remove the wires from the terminals, and test for continuity. Lift the float, and there should be no continuity. Let the float rest, and you should have continuity. If the test fails, replace the float switch. __-36 Testing the float switch contacts. 7. Remove the float switch To remove the float switch, you will have to remove the screws that hold the switch in place (Fig. 37). 8. Install a new float switch To install the new float switch, just reverse the disassembly procedure, and reassemble. Then, reconnect the electricity, and test a dishwasher cycle that fills the dishwasher. DIAGNOSTIC CHARTS The following diagnostic charts will help you to pinpoint the likely causes of the various dishwasher problems (Figs. __38 through __44). Schematics (Figs.__45 through __47). __-37 An exploded view of the float switch assembly Dishwasher will not run at all. Check for voltage at the outlet. Do you have … 115 volts? Yes Check timer. No Replace timer. “0” Ring Float assy. Switch Check fuse or circuit breakers Replace fuse or reset circuit breakers No/Yes Check for loose wire connections or burnt wires. Check door switch and latch assey. Repair or replace loose connections or burnt wires Replace switch or adjust latch assey. __-38 Dishwasher diagnostic flow chart: dishwasher will not run at all. Water not entering dishwasher. Turn on power. Start dishwasher. Check for voltage at water valve Operate the water valve till warm. Does the coil open when warm? __-39 Dishwasher diagnostic flow chart: water not entering the dishwasher __-40 Dishwasher diagnostic flow chart: dishwasher runs continuously. Is the water supply turned on to d/w? No -- Turn on water supply. Turn off power. Check continuity of water valve coil. Replace water valve. Check float switch. Replace if necessary. Check wire harness. Replace water valve. Clean water inlet screen in valve body. continuity at the thermostat located / No underneath the tub or in the control panel? Dishwasher motor won’t run. Replace fuse; ck fuse; circuit breaker Replace assembly. Check wiring Replace timer. __-41 Dishwasher diagnostic flow chart: dishwasher motor won’t run. Is the energy -- Instruct customer that saver switch – Yes: the drying time will turned on? -- increase when energy saver switch is off. No: Turn off electric to ; dishwasher. Check for continuity at the cal rod heater. Yes; Turn on electric to 1; dishwasher. Turn timer 1; dial to heat and close / door. Should have 115 volts at calrod heater. Start the dishwasher. Does the motor attempt to run? Yes Turn electric off to dishwasher. Check motor for continuity. Dishwasher not drying. __-42 Dishwasher diagnostic flow chart: dishwasher won’t dry. Water in tub at end of cycle. On some models water remaining is normal. On those models water level should be below heater at end of cycle. Fill dishwasher then turn timer dial to pump out water. Start dishwasher. Check continuity of motor. On some models check continuity on drain valve solenoid coil. Does the motor _______ and the pump -- No assembly work at all? Yes Check the motor overload. A cold motor should not trip the overload on locked rotor in less than two minutes. Yes; Replace the motor. Yes /No 1. Replace motor 2. Replace valve. Check voltage at drain valve coil. 115V? Clean the drain line; No -- On all models is the drain line clear? __-43 Dishwasher diagnostic flowchart: water in the tub at the end of cycle. Water valve noise chart: Complaint; When noise occurs; Which water valve parts External factors: Makes a “hissing” to a shrill whistle. Low frequency “rumble.” While the water valve is open. When the water valve is about to close. Outlet assembly and hose to fill funnel, flow-washer. Flow-washer. Close or open the supply water valve to change the pressure band. Water heater temperature too high. Set the water heater thermostat to 140 degrees Fahrenheit. Low frequency pulsing. The water valve will make a single “thud.” When the water valve closes, At closing. Spring, diaphragm. Armature spring, diaphragm. * Long runs of unsupported pipes. You must secure the pipes to stop any vibrations. * Water supply line to the water valve is undersized. Must have 3/8’ I.P.S. or 1/4’ ID. * Water heater temperature is too high. Set the water heater thermostat at 150 degrees Fahrenheit maximum. __-44 Water valve noise chart. Push button switch contacts are closed. The wash cycle has already been selected for you. __-45 The typical dishwasher electrical schematic. The wash cycle has already been selected. The pushbutton switch contacts are closed. Typical dishwasher electrical schematic __-46 This illustration shows the active circuits, while the dishwasher tub is filling up with water Push button switch contacts are closed. The wash cycle has already been selected for you. __-47 This illustration shows the active circuits, while the dishwasher is draining the water out of the tub.
Prev: Appliance parts |
Next: Garbage disposers |