Condenser coils located inside the freezer's walls do not need cleaning. However, externally accessed coils behind or below the cabinet should be cleaned every 6-12 months. Dirty condenser coils cannot dissipate heat properly, harming cooling performance. Dust and debris act as insulation that inhibits airflow through the condenser. This forces the compressor to work harder reducing cooling capacity. If the accessible condenser coils are visibly dirty or have not been cleaned in over a year, they should be cleaned.
The temperature control thermostat regulates electrical power to the compressor, evaporator fan, and condenser fan. A malfunctioning thermostat can cause continuous freezer operation. To check it, turn the temperature dial from the coldest to warmest setting. If you hear a "click" sound, the thermostat is likely functional. If it does not click, use a multimeter to test for continuity. If the thermostat contacts remain closed at all settings, it is defective and needs replacing. A faulty thermostat fails to properly control voltage to the components. Replacing the defective thermostat will restore normal on/off cycling based on temperature settings.
The evaporator fan pulls air over the cooling coils and circulates it in the freezer. Typically these motors shut off when the door opens. First, ensure the door is fully closed to engage the door switch. If the switch is on but the fan still won't run, the evaporator motor needs replacing. The sealed fan motor may have internal failure or locked rotor. Check for obstructions like ice buildup as well. Replacing a burned out or malfunctioning evaporator fan motor will reestablish proper airflow when the door switch activates.
The condenser fan pulls air through the condenser coils to remove heat. If this fan stops running, first inspect the blades for blockages and ensure they spin freely. If the blades do not rotate smoothly, the fan motor bearings are worn out requiring replacement. If no obstructions are present and blades move freely, use a multimeter to check continuity in the windings. If testing shows the sealed motor is electrically open, it needs replacing. Replacing a burned out condenser fan motor or one with bad bearings will reestablish proper airflow through the condenser for heat dissipation.
The defrost timer periodically turns on the defrost heater to clear frost accumulating on the evaporator coils. If the heater fails to activate, ice will continue building up and eventually block airflow. For the timer to initiate defrost mode, its internal motor must advance into the defrost cycle position. If the timer motor stalls, the heater won't turn on. To test, manually rotate the timer until it clicks off the compressor/fans. If the defrost heater then activates properly, the timer is faulty and requires replacement. A stalled timer will prevent defrost cycles from running.
The freezer thermistor is a temperature sensor located inside the freezer compartment. It measures the air temperature and provides input to the control board. The control board uses this input to determine when to turn the cooling system on and off. If the thermistor fails, the control board will not receive accurate temperature readings. A damaged thermistor may improperly sense very high temperatures even when the freezer has reached the set point. The control board then falsely believes the freezer needs cooling and keeps the compressor and evaporator fan running nonstop. Replacing the faulty thermistor with a new one restores accurate temperature data to the control board.
The freezer door gasket is a rubber seal that runs around the perimeter of the freezer door. Its purpose is to form an airtight seal between the freezer door and the freezer cabinet when the door is closed. If the gasket becomes damaged or worn out, it can lose its ability to seal properly. Air gaps and leaks will then form around the freezer door. This allows cold air to escape from the freezer and warmer ambient air to seep in. To compensate for the heat gain, the freezer will run its cooling system continuously in an attempt to maintain the set freezer temperature. Replacing the worn or damaged freezer door gasket will re-establish the proper seal and allow the freezer to operate normally.
The main control board is often misdiagnosed as faulty when other parts are the real culprit. Prior to replacing the control board, first verify proper operation of common failure points like the compressor, fans, thermostat, and timers. Only replace the board once other components are confirmed to be working correctly. The control board relies on proper inputs to direct operation of the various electrical components. Faulty parts can provide incorrect signals to the board and mimic a control defect. Therefore, rule out malfunctioning parts first before assuming control board failure.
Freezers have a door closing cam that holds doors open and draws them shut. If this cam is damaged, the door may not fully close on its own. Gaps left by improper closure let warm air enter the freezer interior. This causes the compressor to run excessively trying to cool the warmer air. Inspect the closing cam for any broken parts, wear, or defects preventing proper function. Check that the door is closing completely when shut. If the cam is damaged and unable to close the door, replace it.
The freezer thermistor is a temperature sensor located inside the freezer compartment. It measures the air temperature and provides feedback to the control board. The control board uses this temperature reading to regulate the compressor and refrigerant flow to maintain the target freezer temperature. If the thermistor is defective, it may fail to provide an accurate temperature reading to the control board. As a result, the freezer will be unable to maintain freezing temperatures. To test the thermistor, use a multimeter to check its resistance at various temperatures and compare to the resistance values listed on the tech sheet. If the resistance readings do not align with the spec, the thermistor is defective and needs to be replaced.
The freezer control board is the main electronic control center that regulates the operation of the freezer. It controls when the compressor turns on and off based on input from the thermostat temperature sensor. A malfunctioning freezer control board can incorrectly command the compressor to run continuously, even when the set temperature has been reached. This causes the freezer to run excessively as it tries to cool to a temperature lower than what is set. A defective control board may fail to send the signal to turn the compressor off, or inaccurately sense that the freezer temperature is higher than it actually is. Replacing the faulty control board with a properly working one will restore the proper on/off compressor cycling needed to maintain the set freezer temperature without continuous operation.
The defrost heater periodically activates to melt frost on the evaporator coils. First, the defrost thermostat must sense the coils are sufficiently cold before allowing heater operation. Typically the coils must be below 30°F for the thermostat to close its contacts. If defective, the thermostat won't activate the heater even when cold enough. This allows frost accumulation on the coils over time. Use a multimeter to check the thermostat switch contacts for electrical continuity. If testing shows the thermostat remains open regardless of temperature, replace it.
Ensure the freezer doors are closing completely and sealing properly. A door prevented from full closure can prevent proper cooling. Check that storage bins or food packages are not obstructing the door. Any gap caused by an obstruction can allow warm air into the freezer interior. This makes the compressor run constantly in an attempt to maintain temperature. Blocked doors also disrupt air circulation needed for even cooling.
Freezers are designed to operate optimally in 60°F to 95°F room temperatures. Performance suffers as ambient air becomes hotter and more humid. Warmer conditions force the compressor to run more to maintain freezing temperatures. For best efficiency, keep the surrounding air within the 60°-95°F range.
Chest freezers contain evaporator coils concealed in the insulating walls. Upright models may use shelves as the cooling coils. If only one shelf or section frosts up during operation, there may be a refrigerant leak. Leaks in the sealed cooling system are typically uneconomical to repair. Loss of refrigerant indicates the sealed components have failed. Freezers cannot operate properly without an intact, pressurized refrigeration circuit. So a leaking sealed system usually requires total freezer replacement.