Sunday, June 12, 2016

Refrigerator common faults and solution – Home appliances repair and service

Category: Home Appliances Repair and Service 

Contents of this article 

  • Refrigerator Not cooling 
  • Refrigerator Not defrosting 
  • Refrigerator runs continuously 

Refrigerator common faults 

Not Cooling
1. Condenser Coils are Dirty
The condenser coils are usually located under the refrigerator. They dissipate heat as refrigerant passes through them. If the condenser coils are dirty, they won’t dissipate the heat effectively. As debris builds up on the coils, the refrigerator becomes less efficient, causing the refrigerator to work harder to cool down. If the coils are significantly dirty, the refrigerator will not be able to maintain the proper temperature. Check the condenser coils to determine if they are dirty,if the condenser coils are dirty, clean them.
2. Evaporator Fan Motor
The evaporator fan motor draws air over the evaporator (cooling) coils and circulates it throughout the refrigerator and freezer compartments. Some refrigerators have more than one evaporator fan motor. On refrigerators with only one evaporator, the evaporator is located in the freezer compartment. If the evaporator fan is not working, it will not circulate the cold air to the refrigerator compartment. If this occurs, the freezer may still get cold, while the refrigerator will not get cold. To determine if the evaporator fan motor is defective, try turning the fan blade by hand. If the fan blade does not turn freely, replace the fan motor. Additionally, if the motor is  noisy, replace it. Finally, if the motor does not run at all, use a multimeter to test the motor winding for continuity. If the winding do not have continuity, replace the evaporator fan motor.
3. Condenser Fan Motor
The condenser fan motor draws air though the condenser coils and over the compressor. If the condenser fan motor is not working properly, the refrigerator won’t cool properly. To determine if the fan motor is defective, first check the fan blade for obstructions. Next, try turning the fan motor blade by hand. If the blade does not spin freely, replace the condenser fan motor. If no obstructions are present and the fan blade spins freely, use a multimeter to test the fan motor for continuity. If the condenser fan motor does not have continuity, replace it.
4. Start Relay
The start relay works in conjunction with the start winding to start the compressor. If the start relay is defective, the compressor may sometimes fail to run or may not run at all. As a result, the refrigerator will not be cold enough. To determine if the start relay is defective, use a multimeter to test it for continuity between the run and start terminal sockets. If the start relay does not have continuity between the run and start terminal sockets, replace it. In addition, if the start relay has a burnt, replace it too.
5. Temperature Control Thermostat
The temperature control thermostat directs voltage to the compressor, evaporator fan motor, and condenser fan motor (if applicable). If the temperature control thermostat is not working properly, it may prevent the refrigerant system from running. To determine if the thermostat is defective, rotate the thermostat from the lowest setting to the highest setting and listen for a click. If the thermostat clicks, it is not likely defective. If the thermostat does not click, use a multimeter to test the thermostat for continuity. If the temperature control thermostat does not have continuity at any setting, replace it.
6. Start Capacitor
The start capacitor provides a boost of power to the compressor during start-up. If the start capacitor isn’t working, the compressor may not start. As a result, the refrigerator will not cool. To determine if the start capacitor is defective, test it with an LCR multimeter. If the start capacitor is defective, replace it.
7.Thermistor
The thermistor monitors the refrigerator temperature and sends the temperature reading to the control board. The control board regulates power to the compressor and evaporator fan based on the thermistor readings. If the thermistor is defective, the compressor and evaporator fan may not run when necessary. As a result, the refrigerator will not be cold enough. To determine if the thermistor is defective, test it with a multimeter. The thermistor resistance should change in conjunction with the refrigerator temperature. If the thermistor resistance does not change, or the thermistor does not have continuity, replace the thermistor.
8. Temperature Control Board
The temperature control board provides voltage to the compressor and fan motors. If the temperature control board is defective, it will stop sending voltage to the cooling system. However, this is not a common occurrence. Control boards are often misdiagnosed, before replacing the control board, first test all of the more commonly defective components. If none of the other components are defective, consider replacing the temperature control board.
9. Compressor
The compressor is a motor which compresses the refrigerant and circulates the refrigerant through the evaporator and condenser coils. If the compressor is not working, the refrigerator won’t cool. However, this isn’t usually the case. Before replacing the compressor, first check for defective components. If all of the other components are working properly, use a multimeter to test the compressor winding for continuity. If the compressor winding does not have continuity, replace it.
10. Main Control Board
The main control board might be defective. However, this is almost never the cause. Before replacing the main control board, test for defective parts. If none of the other components are defective, consider replacing the main control board.
Water Dispenser Not Working
1. Water Tube in Door is Frozen
To determine if the water supply tube is frozen, disconnect the tube at the bottom of the door and blow air through it. If air does not pass through, this indicates that the water supply tube is frozen. If the water supply tube is frozen, thaw it out. In addition, ensure that the freezer is kept at the proper temperature. The freezer temperature should be kept from 0-10 degrees Fahrenheit. If the freezer is too cold, the water line may freeze.
2. Water Inlet Valve
The water inlet valve opens to supply water to the dispenser. If the water inlet valve is defective, or if the water pressure is too low, the water valve will not open. The valve requires at least 20psi to function properly. Make sure that the water pressure to the valve is at least 20 psi. If the water pressure is sufficient, use a multimeter to test the water inlet valve for continuity. If the water inlet valve does not have continuity, replace it.
3. Low Water Pressure from House Supply
The home may have insufficient water pressure. The water inlet valve supplies water to the water dispenser. The water inlet valve requires a minimum of 20 psi to function properly. Check the water flow and test the pressure to determine if it is at least 20 psi.
Ice Maker Not Working
1. Freezer Temperature is Above 10 Degrees F (-12 Degree C)
If the freezer temperature is above 10 degrees Fahrenheit (-12C), the ice maker will not produce ice cubes efficiently. The freezer temperature should be set between 0 and 5 degrees Fahrenheit (-18 to -15 Degree C) for the ice maker to work properly. If the freezer temperature is too high, ensure that the condenser coils are clear of debris and the condenser fan is working properly. In addition, check to see if frost has accumulated on the evaporator coils. If the evaporator coils are frosted over, part of the defrost system has likely failed.
2. Water Inlet Valve
The water inlet valve is an electrically-controlled valve that opens to supply water to the dispenser and ice maker. If the water inlet valve is defective, or if it has insufficient pressure, it won’t allow water to flow through. As a result, the ice maker won’t make ice. The valve requires at least 20 psi to function properly. Make sure that the water pressure to the valve is at least 20 psi. If the water pressure is sufficient, use a multimeter to check for power to the water inlet valve. If the water inlet valve has sufficient pressure and is getting power, but the ice maker won’t fill with water to make ice, replace the water inlet valve.
3. Ice Maker Assembly
Since many of the ice maker components are not sold separately, you may need to purchase and replace the entire ice maker assembly. Before replacing the ice maker assembly, check the water inlet valve, water line, and fan. If none of these parts are faulty, and the freezer temperature is not at least 15 degrees Fahrenheit, replace the ice maker assembly.
Ice Dispenser Not Working
1. Dispenser Control Board
The dispenser control board governs most of the functions of the dispenser system. If the control board is faulty, it may stop supplying power to the entire dispenser system. If only one dispenser part is not working, test each of the dispenser components before testing the control board. May be single part has failed. If the entire dispenser system is not working, the control board is more likely to be at faulty.
2. Dispenser Switch
The dispenser switches send voltage to the dispenser. If one of the dispenser switches is defective, the dispenser will not work. To determine if a dispenser switch is defective, use a multimeter to test each switch for continuity. If a dispenser switch does not have continuity, replace it.
3. Dispenser Actuator
The dispenser actuator interacts with the dispenser switches, which power the auger motor and other dispenser components. If the dispenser actuator is broken, it may not activate the switches properly or at all. Inspect the dispenser actuator, if it is broken replace it.
Not Defrosting
1. Defrost Control Board
The defrost control board determines how often to run the defrost cycle. If the board fails, the refrigerator will not go into the defrost cycle. Before replacing the defrost control board, first test the defrost heater and defrost thermostat. If the defrost heater and defrost thermostat are working properly, the defrost control board is likely defective.
2. Defrost Timer
The defrost timer turns on the defrost heater several times throughout the day to melt any frost that may have accumulated on the evaporator coils. If the defrost timer is defective, it may not advance into the defrost cycle, or it may not send power to the defrost heater during the defrost cycle. To determine if the defrost timer is defective, slowly advance the dial into the defrost cycle. The compressor should turn off and the heater should turn on. If the timer does not send power to the defrost components or advance out of the defrost cycle within 30 minutes, this indicates that the defrost timer is not working. If the defrost timer is not working, then replace it.
3. Defrost Heater Assembly
The defrost heater assembly turns on several times throughout the day to melt away any frost that may have accumulated on the evaporator coils. If the defrost heater assembly is defective, the defrost system will not work, and frost will continue to accumulate on the evaporator coils. To determine if the defrost heater is defective, use a multimeter to test it for continuity. If the defrost heater does not have continuity, then replace it.
Noisy
1. Fan Blade
If the refrigerator is noisy or loud, especially when the door is opened, either the evaporator or condenser fan blade may be at fault. First, turn the evaporator fan blade by hand. If the fan blade does not turn freely, check to see if the blade is rubbing against something or if something is caught in the blade. Additionally, check the condenser fan blade to determine if it has any obstructions.
2. Evaporator Fan Motor
When the evaporator fan motor fails, it often generates a lot of noise. This noise will be much louder when the refrigerator door is opened. If the evaporator fan is noisy,then replace it.
3. Condenser Fan Motor
There might be something caught in the condenser fan motor blade, or the condenser fan motor bearings might be defective. The condenser fan motor is usually located underneath the refrigerator near the back. Pull the refrigerator out from the wall and remove the access panel to access it.
Freezer is Cold But Refrigerator is Warm
1. The Evaporator Coils are Frosted Over
The defrost heater assembly turns on a few times throughout the day to melt away any frost that may have accumulated on the evaporator coils. If the defrost heater assembly is defective, frost will continue to accumulate on the evaporator coils, and the coils will become plugged with frost. If the evaporator coils are frosted over, the airflow through the coils will be restricted, causing the refrigerator not to cool. Check the evaporator coils to determine if they are frosted over. If the evaporator coils are frosted over, test each component of the defrost system.
2. Evaporator Fan Motor
The evaporator fan motor draws cold air over the evaporator coils and circulates it throughout the freezer. If the evaporator fan is not working, the freezer or refrigerator will not cool adequately. To determine if the evaporator fan motor is defective, try turning the fan blade by hand. If the fan blade does not turn freely, replace the fan motor. Additionally, if the motor is noisy, replace it. Finally, if the motor does not run at all, use a multimeter to test the motor winding for continuity. If the winding do not have continuity, replace the evaporator fan motor.
3. Damper Control Assembly
The air damper control opens and closes to let the proper amount of cold air into the refrigerator compartment. If the damper does not open properly, it won’t let enough cold air into the refrigerator. Check the damper control to determine if it is broken or closed.
Defrost Drain Freeze
1. Freezing Defrost Drain
The defrost drain might be clogged or frozen. If the defrost drain is frozen, the water will overflow trough drain  and drip down to the bottom of the compartment. If the defrost drain is frozen, thaw it out and ensure that the drain is clear of debris.
2. Drain Strap
Some defrost drains are outfitted with a drain strap. The drain strap is a small piece of copper or aluminum that attaches to the defrost heater and extends partway into the defrost drain. When the defrost heater turns on, heat is conducted through the drain strap to melt away any ice that may have accumulated further down in the defrost drain. If the drain strap is not in place, the defrost drain may be more likely to freeze over.
3. Drain Heater
Some refrigerators are equipped with drain heaters. Drain heaters prevent the water in the drain pan from re-freezing and clogging the defrost drain. If your drain heater is defective or is not in the proper position, the defrost drain might freeze over.
Water leakage 
1. Freezing Defrost Drain
If the defrost drain is frozen, the water will overflow the drain trough and drip down to the bottom of the compartment. This water can eventually leak onto the floor. Check the defrost drain to determine if it is clogged or frozen. If the defrost drain is frozen, thaw the ice. In addition, flush the drain with hot water to ensure that it is clear of debris.
2. Water Tank Assembly
Inspect the water tank assembly for any leaks. Be aware that the leak may be very small and hard to find. If you discover a leak, replace the water tank. Do not attempt to repair the water tank, glue will not stick properly to the plastic protion of the tank.
3. Water Inlet Valve
The water inlet valve opens to, supply water to the dispenser and icemaker. If the water inlet valve is cracked or has a loose fitting, water will leak from the valve. Inspect the water inlet valve for cracks, and make sure that it is tightly secured to the water supply line.
Freezing Food
1. Temperature Control Thermostat
The temperature control thermostat directs voltage to the compressor, evaporator fan motor, and condenser fan motor (if applicable). If the temperature control thermostat is not working properly, it may cause the refrigerant system to run longer than necessary. As a result, the refrigerator will be too cold. To determine if the thermostat is defective, rotate the thermostat from the lowest setting to the highest setting and listen for a click. If the thermostat clicks, it is not likely defective. If the thermostat does not click, use a multimeter to test the thermostat for continuity. If the temperature control thermostat does not have continuity at any setting, replace it.
2. Thermistor
The thermistor monitors the air temperature and sends the temperature reading to the control board. The control board then regulates power to the compressor and evaporator fan based on the thermistor readings. If the thermistor is defective, the compressor and evaporator fan may run too frequently. As a result, the refrigerator will be too cool. To determine if the thermistor is defective, test it with a multimeter. The thermistor resistance should change in conjunction with the refrigerator temperature. If the thermistor resistance does not change, or the thermistor does not have continuity, replace the thermistor.
3. Temperature Control Board
The temperature control board provides voltage to the compressor and fan motors. If the control board is faulty, it may send continuous voltage to the compressor or fan motors. As a result, the refrigerator will be too cool. Control boards are often misdiagnosed, before replacing the control board, first test for other defective components. If none of the other components are defective, consider replacing the temperature control board.
Ice And Water Dispenser Not Working
1. Dispenser Control Board
The dispenser control board governs most of the functions of the dispenser system. If only one dispenser part is not working, it is probable that an individual part has failed. In this case, test each of the dispenser components before testing the control board. If the entire dispenser system is not working, the control board is more likely to be at 
2. Dispenser Switch
The dispenser switches send voltage to the dispenser. If one of the dispenser switch is defective, the dispenser will not work. To determine if a dispenser switch is defective, use a multimeter to test each switch for continuity. If a dispenser switch does not have continuity, replace it.
3. Door Switch
The door switch turns off the ice and water dispenser when the refrigerator door is open. If the door switch fails, the dispenser will not turn on. To determine if the door switch is defective, use a multimeter to test it for continuity. If the door switch does not have continuity when activated, replace it.
Ice Maker Overflowing
1. Water Inlet Valve
The water inlet valve requires a minimum of 20 psi to shut off properly. If the water pressure is too low, the valve may not close fully once the power is shut off. As a result, the valve will leak water into the ice maker and cause the ice maker to overflow. Check the water pressure to determine if it is at least 20 psi. If the water pressure is sufficient, the water inlet valve is likely defective. The valve may not shut off all the way or may be stuck open, causing water to leak through the valve. If the water pressure is sufficient, but the ice maker is still overflowing, replace the water inlet valve.
2. Low Water Pressure from House Supply
The water inlet valve supplies water to the refrigerator ice and water dispenser. The valve requires a minimum of 20psi to work properly. If the water pressure is too low, the valve may not close fully when the power is shut off. As a result, the valve leaks water into the ice maker, causing it to overflow. Check the water flow and test the pressure to determine if it is at least 20 psi.
3. Ice Maker Assembly
Since many of the ice maker components are not sold separately, you may need to purchase and replace the entire ice maker assembly.
Light Not Working
1. Light Assembly
The light assembly might be defective. Some manufacturers don’t sell the bulb separately, and instead require you to purchase the light assembly.
2. Light Switch
To determine if the light switch is defective, use a multimeter to test it for continuity. If the light switch does not have continuity, replace it.
3. Door Switch
To determine if the door switch is defective, use a multimeter to test it for continuity. If the door switch does not have continuity when activated, replace it.
4. Light Socket
To determine if the light socket is defective, use a multimeter to determine if the socket is getting power. If the socket is getting power, but the bulb won’t work, this indicates that the light socket is defective. If the light socket is defective, replace it.
5. Light Board
First, ensure that the light board is receiving the proper amount of voltage. If the light board is receiving sufficient voltage, but the refrigerator light will not work, replace the light board.
Runs Constantly
1. Condenser Coils are Dirty
The condenser coils are usually located under the refrigerator. They dissipate heat from the refrigerator as refrigerant passes through them. If debris accumulates on the coils, the refrigerator will have to work harder to remove the heat. If the coils are significantly dirty, the refrigerator will run constantly in an effort to cool down. Your refrigerator’s condenser coils should be cleaned twice a year.
2. Freezer Temperature is Above 10 Degrees F (-12C)
If the freezer temperature is above 10 degrees Fahrenheit (-12 Degree C), the refrigerator will not be cold enough. If the refrigerator is not cold enough, it will work harder to cold down. As a result, it will run constantly. The freezer temperature should be set between 0 and 5 degrees Fahrenheit (-18 to -15 Degree C). If the freezer temperature is too high, ensure that the condenser coils are clear of debris and the condenser fan is working properly. In addition, check to see if frost has accumulated on the evaporator coils. If the evaporator coils are frosted over, part of the defrost system has likely failed.
3. Defrost Heater Assembly
The defrost heater assembly turns on several times throughout the day to melt away any frost that may have accumulated on the evaporator coils. If the defrost heater assembly is defective, the refrigerator will not defrost, and frost will continue to accumulate on the evaporator coils. If the evaporator coils are frosted over, the refrigerator will work harder to remove the heat. As a result, the refrigerator will run constantly in an effort to cool down. To determine if the defrost heater is defective, use a multimeter to test it for continuity. If the defrost heater does not have continuity, replace it.
4. Defrost Thermostat
If the refrigerator runs constantly, the defrost thermostat might be defective. Several times a day the defrost heater turns on for a few minutes to melt away any frost that may have accumulated on the freezer or refrigerator evaporator coils. In order for this to work, the defrost thermostat has to sense that the coils are cold enough. If the coils are cold enough the defrost heater will turn on. If the thermostat is defective it may not be able to sense the temperature of the coils and then won't turn on the defrost heater. If the defrost heater doesn't turn on, the frost will build up on the coils and eventually no air will be able to travel through the coils to provide cooling . The defrost thermostat can be checked for continuity. It should have continuity when it reaches the low temperature of its operating range.
5. Door Gasket
If the Refrigerator runs constantly the door gasket may be torn or defective, or if the door is not shutting tightly warm air can enter the the refrigerator and cause the evaporator coils to ice over. This happens because humid air from the room is drawn into the refrigerator through the opening at the gasket. As the humidity comes in contact with the cold evaporator coils it condenses and freezes. Normally the defrost system removes this frost and ice. However, if the door gasket is defective the evaporator coils ice over too quickly and the defrost cycle cannot keep up.
6. Evaporator Fan Motor
If the refrigerator runs constantly, the evaporator fan motor might have failed. Every refrigerator has a set of coils called an evaporator. The refrigerator may have one or more evaporator fan motors depending on the model and evaporator locations. The evaporator fan motor circulates the cold air from the coils thru the compartment. If there is only one evaporator it is in the freezer side. If the fan is not working, no cold air will get to the refrigerator compartment. The freezer may still get cold.
7. Defrost Control Board
If the refrigerator runs constantly, the defrost control board might be defective. The defrost control board monitors several conditions and determines how often to run the defrost cycle. If the board fails, the refrigerator will not go into the defrost cycle. Eventually, ice will build up on the evaporator coil and then the refrigerator and or freezer will not stay cold enough. This will depend on where the evaporator is located. It's prudent to check the defrost heater and defrost thermostat for continuity before replacing the defrost control board.
8. Defrost Timer
If the refrigerator runs constantly, the defrost timer might be defective. Two or three times a day the defrost timer is supposed to turn on the defrost to melt away any frost that may have accumulated on the freezer evaporator coils. If the timer is defective it won't advance and won't turn on the heater.
9. Condenser Fan Motor
If the refrigerator runs constantly there might be something caught in the condenser fan motor blade, or the condenser fan motor might be defective. The condenser fan motor draws air over the condenser coils to cool them. The condenser fan motor is located underneath the refrigerator near the back. Pull the refrigerator out from the wall and remove the access panel to access it.