644 Modern Refrigeration and Air Conditioning Copyright Goodheart-Willcox Co., Inc. After the visual inspection, the next step in diag- nosing a system is to determine the possible causes of the symptoms. Troubleshooting charts are very useful for determining possible causes. A troubleshooting chart lists common troubles, symptoms, their causes, and remedies, Figure 25-5. Next, repair or correct the problem. If the prob- lem could have been a possible cause of the initial symptoms, retest the system to determine whether the service corrected the problem. If the service you per- formed did not correct the symptoms, continue diag- nosing the system. Troubleshooting Chart—Domestic Refrigerator-Freezers Trouble Common Cause Remedy Unit will not run. 1. Blown fuse. 2. Low voltage. 3. Broken motor or temperature control. 4. Broken relay. 5. Broken overload protector. 6. Broken compressor. 7. Defective power cord. 8. Broken lead to the compressor, timer, or thermostat. 9. Broken timer. 1. Replace the fuse. 2a. Check the outlet with a voltmeter. It should measure 115 V plus or minus 10%. 2b. If the circuit is overloaded, either reduce the load, or have an electrician install a separate circuit. 2c. If you are unable to remedy the problem any other way, install an auto-transformer. 3. Install a jumper across the terminals of the control. If the unit runs and all connections are tight, replace the control. 4. Check the relay and replace as needed. 5. Check the overload protector and replace as needed. 6. Check the compressor and replace as needed. 7. Check the cord using a test light at the unit. Replace the cord if there is current at the outlet but not at the unit. 8. Repair or replace the broken leads. 9. Check the timer with a test light and replace as needed. Refrigerator section too warm. 1. Repeated door openings. 2. Overloading of shelves, blocking the normal airflow in the cabinet. 3. Warm or hot foods placed in cabinet. 4. Poor door seal. 5. Interior light stays on. 6. Refrigerator section airflow controls improperly set or malfunctioning. 7. Cold control knob set at too warm a position, not allowing the unit to operate often enough. 8. Freezer section grille not properly positioned. 9. Freezer fan not running properly. 10. Defective compressor intake valve. 11. Air duct seal not properly sealed or positioned. 1. Instruct user. 2. Instruct user. 3. Instruct user to allow foods to cool to room temperature before placing in the cabinet. 4. Level the cabinet and adjust the door seal. Replace the gasket if necessary. 5. Check the light switch and replace as needed. 6a. Turn the control knob to a colder position. Check the airflow heater. 6b. Check the damper for proper operation by removing the grille. With the cabinet door open, the damper should open. If the control is inoperative, replace the control. 7. Turn the control knob to a colder position. 8. Reposition the grille. 9. Replace the fan, fan switch, or defective wiring. 10. Replace the compressor. 11. Check and reseal or put the seal in the correct position. Goodheart-Willcox Publisher Figure 25-5. Common domestic refrigerator-freezer troubles, their causes, and suggested remedies. This particular chart should be considered a general guide only. It does not apply to all units. (continued).