You depend on your refrigerator to work as intended to preserve perishable foods, keep beverages refreshingly chilled, and to freeze meats, vegetables, or frozen treats for future use. But if your refrigerator seems to be “running” all the time, then the appliance is working too hard. While having a refrigerator that works overtime might give the impression the appliance is especially robust, it’s actually an indication that something is wrong with the unit.
That sound of a refrigerator “running” is the sound of the unit’s compressor turning on, combined with the whirring of the evaporator and condenser fan blades. Understanding how the compressor and refrigerant system functions is the first step in successfully troubleshooting why your refrigerator runs constantly.
How a refrigerator’s refrigerant system works
While we may think of a refrigerator as an appliance that creates coldness, it’s more accurate to say that the refrigeration system removes the heat from the air traveling through the refrigerator and freezer compartments. The more heat and humidity that is removed, the colder those compartments will be. To accomplish this, a refrigerator uses a compressor to pump refrigerant through a set of coils, and fan motors to circulate the air. The compressor compresses the refrigerant in gas form into the condenser coils (often located at the bottom of the appliance) where the gas is then condensed into a hot liquid. The condenser coils dissipate the heat as the liquid travels through them. When the refrigerant reaches the evaporator coils (usually located behind a rear panel in the freezer compartment, although some models will place these coils behind a rear panel in the refrigerator compartment), it expands back into a gas which makes the coils cold. The gas continues to flow through a suction line attached to the compressor which compresses the gas back into the condenser coils (which condenses the gas back into a hot liquid) and the cooling cycle repeats. A condenser fan motor assists the condenser coils in dissipating the heat while an evaporator fan motor draws air over the cold evaporator coils then circulates that air through the refrigerator and freezer compartments.
Your refrigerator should maintain a consistently cool temperature around 40° Fahrenheit (4° Celsius) in the refrigerator compartment and 0° Fahrenheit (-18° Celsius) in the freezer compartment. However, the compressor and fan motors should only have to run occasionally throughout the day to maintain that cool temperature. If the compressor and fan motors are continuously running, it means the system is having trouble maintaining the temperature.
6 reasons why your refrigerator runs constantly
Leaving the refrigerator or freezer doors open too long will, of course, allow the cool air to escape and raise the temperature inside the compartments. This is why you will often hear the compressor start up if it’s taking you a while to locate those left-overs that got pushed back behind the pickle jar. That’s normal. But if the refrigerator seems to be running constantly with the doors fully closed, here are six potential issues you should investigate:
- Dirty condenser coils – Over time, the condenser coils will collect dust, dirt, and hair, preventing the coils from properly dissipating the heat. When this happens, the compressor will continue to run since it is unable to cool the compartments efficiently. You can use a condenser coil brush to clean off the coils periodically to ensure optimum refrigerator operation.
- Defective defrost heater assembly – The evaporator coils collect frost as the air passes through them to cool the compartments. Since frost build-up can cause air flow problems, the coils require periodic defrosting. If the defrost heater assembly is defective, the evaporator coils will frost over, restricting air flow and causing the compressor to run continuously. You can use a multimeter to test the defrost heater for electrical continuity, a continuous electrical path present in the component. If the heater tests “negative” for electrical continuity, you will need to replace it with a new heater.
- Malfunctioning defrost thermostat – The defrost thermostat monitors the temperature of the evaporator coils. When the temperature drops to a set level, the contacts in the thermostat close and allow voltage to power the defrost heater. A malfunctioning thermostat may prevent the heater from working. As with the heater assembly, you can use a multimeter to test the defrost thermostat for electrical continuity to determine if the part is defective. Keep in mind, you must perform this test at a temperature of 15° Fahrenheit (- 9.4° Celsius) or lower for a proper reading.
- Defective evaporator fan motor – Since the evaporator fan motor draws the air over the evaporator coils to cool it and then circulate that air through the compartments, a defective fan motor could cause the compressor to run excessively. If the motor is unusually noisy when the refrigerator is running, or the fan blade does not turn freely, it’s likely the motor bearings have seized. You can also test the evaporator fan motor with a multimeter to help determine if the component has failed electrically.
- Malfunctioning condenser fan motor – A malfunctioning condenser fan motor can cause the same problem by failing to draw air past the condenser coils. Check for a broken fan blade or a blade that will not turn freely. If the motor is receiving power, but doesn’t run, then the motor has probably failed electrically.
- Worn door gasket – If the refrigerator or freezer door gasket is worn or kinked, the cool air could be escaping the compartments and warm, moist air could be entering. This can cause the evaporator coils to frost over which will, in turn, cause the compressor to run continuously. Fortunately, door gaskets are relatively easy to install for even a beginning do-it-yourselfer.
Keep the refrigerator running right (not constantly) with Repair Clinic
Whether you need a new defrost heater, defrost thermostat, evaporator fan motor, condenser fan motor, or door gasket to keep your refrigerator operating at its best, Repair Clinic.com has the genuine manufacturer replacement parts you need from all the top brands, including Samsung, Frigidaire, KitchenAid, GE, Kenmore, LG, Maytag, and Whirlpool. To get started, enter the full model number of your refrigerator into the Repair Clinic website search bar. You can then use the “Part Category” filter (“Thermostat”/ “Gasket & Seal”) and the “Part Title” filter (“Defrost Thermostat”/ “Door Gasket”) to identify the exact part that fits your model.
In addition to millions of replacement parts, Repair Clinic also has thousands of “how-to” videos, schematics, and articles to guide you, step-by-step, through the part replacement procedure, so you can complete the repair yourself quickly and successfully.