Chapter 25 Installation and Troubleshooting of Domestic Refrigerators and Freezers 645 Copyright Goodheart-Willcox Co., Inc. 8 A methodical approach is needed to find the cause of poor operation. Always remember, cooling occurs only when the evaporator pressure is low enough and liquid refrigerant is present in the evaporator. For example, if an evaporator has the correct low pressure but is warm, it indicates there is no liquid in the evaporator. In another example, a drier in the liquid line is frosting over. There is liquid refrigerant, but the drier is absorbing heat for some reason. An evaporator absorbs heat because the refrigerant is suddenly under much lower pressure than it was in the liquid line. Therefore, something must be causing low pressure Refrigerator section too cold. 1. Refrigerator section airflow control knob turned to coldest position. 2. Airflow control remains open. 3. Broken airflow control. 4. Broken airflow heater. 1. Turn the control to a warmer position. 2. Remove any obstruction. 3. Replace the control. 4. Replace the heater. Freezer section and refrigerator section too warm. 1. Fan motor not running. 2. Cold control set too warm or broken. 3. Finned evaporator blocked with ice. 4. Shortage of refrigerant. 5. Not enough air circulation around the cabinet. 6. Dirty condenser or obstructed condenser ducts. 7. Poor door seal. 8. Repeated door openings. 1. Check the fan motor and replace as needed. 2. Check the control and replace as needed. 3. Check the defrost thermostat or timer. A failure in either of these could cause icing. Replace as needed. 4. Check for and repair leaks. Evacuate and recharge the system. Recover/recycle the refrigerant. 5. Relocate the cabinet or provide adequate clearance to allow sufficient circulation. 6. Clean the condenser and the ducts. 7. Level the cabinet and adjust the door seal. Inspect and replace the gasket if necessary. 8. Instruct user. Freezer section too cold 1. Cold control knob improperly set. 2. Cold control sensing bulb not properly clamped to the evaporator. 3. Broken cold control. 1. Turn the knob to a warmer position. 2. Tighten the clamp or reposition the bulb. 3. Check the control and replace if needed. Unit runs all the time. 1. Inadequate air circulation over the condensing coil. 2. Poor door seal. 3. Freezing large quantities of ice cubes or heavy loading after shopping. 4. Refrigerant undercharge or overcharge. 5. Room temperature too warm. 6. Faulty cold control. 7. Defective light switch. 8. Repeated door openings. 1. Relocate the cabinet to provide adequate clearance. Remove any obstructions to proper airflow over the condenser coil. 2. Check and make necessary adjustments. Inspect and replace the gasket if necessary. 3. Explain to the customer that heavy loading causes long running times. 4. Check, evacuate, and recharge the system with the proper charge. 5. Ventilate the room as much as possible. 6. Check the control and replace if needed. 7. Check the light switch and replace as needed. 8. Instruct user. Noisy operation. 1. Loose flooring or the floor is not firm. 2. Tubing contacting the cabinet or other tubing. 3. Cabinet not level. 4. Drip tray vibrating. 5. Fan is hitting the liner or mechanically grounding. 6. Compressor is mechanically grounded. 1. Tighten the flooring or brace the floor. 2. Reposition tubing as needed. 3. Level the cabinet. 4. Move the tray or place it on a foam pad. 5. Move the fan. 6. Replace the compressor mounts. Goodheart-Willcox Publisher Figure 25-5. Continued.