Maintaining and Troubleshooting Domestic Refrigerators: Chapter 1
Introduction to Routine Maintenance of Domestic Refrigerator
In this module, we will learn about how to perform routine maintenance of domestic refrigerators. Skip to quiz!
Routine Maintenance
Recall that routine maintenance of a system is like a regular check-up for any system. We perform routine maintenance of the refrigerator regularly to ensure that the system works properly.
A refrigerator is one of the few household appliances that run continually, so maintaining it is essential. Taking a few minutes regularly to perform some maintenance tasks will help our unit run more efficiently. This will help to save on energy costs and refrigerator repair bills.
We schedule the periodic maintenance after specific time intervals. These include:
Monthly maintenance,
Every three months,
Every six months, and
Every five year
Before starting the maintenance of the refrigerator, we should follow some safety precautions.
These include:
Turning OFF the refrigerator, and
Wearing safety gloves.
Let us take a look at the maintenance tasks we need to perform periodically.
The maintenance tasks to be carried out every month is as follows:
Cleaning the refrigerator,
Throwing away old foods, and
Ensuring the vents are clear
Let us take a look at each of them.
The cleaning procedure starts with emptying the refrigerator. We should take out all of the removable shelves and drawers. This will give us better access to clean the refrigerator’s interior.
We should thoroughly clean the refrigerator interior with detergent water or vinegar solution. This will wipe off all the spills and stains inside the refrigerator. We should make sure shelves, drawers, and interior are completely dry before refilling the fridge.
While we are refilling the fridge, we should carefully monitor the stuff. We should throw away old, spoiled or expired food. This will prevent odors from old food and make space for new food. If the odors are still present, use baking soda to remove odors.
While we are organizing the food, we should make sure the air vents of air dampers are clear. Recall that the air from the freezer compartment is circulated to the refrigerator using an air damper. Blocking the air vents strains the cooling system, and the refrigerator will consume more electricity.
The maintenance tasks to be carried out every three months is as follows:
Dust the condenser coils,
Grease the gasket, and
Level the feet
Let us take a look at each of them.
Recall that the condenser coils give away heat to the air blown over them. If dust forms over the condenser, it will block the airflow over the coil. So, we should clean the condenser coils using a vacuum cleaner or a brush.
The door gasket is a rectangular rubber ring that helps to seal a door. If it is dirty, damaged, or overly dry, the door won’t seal properly. This will cause cool air from the refrigerator to escape, thus less cooling inside the refrigerator.
We should inspect our door gasket all the way around every three months. If the gasket is dirty or dry, we should clean it.
After cleaning the gasket, we should apply a thin layer of petroleum jelly. A thin coating of petroleum jelly softens a dried gasket to form a good seal around the door of our refrigerator. Let us look at the video that shows periodic maintenance.
We should make sure the fridge is level. If it is leaning from back to front or side to side, it might not close properly. This will reduce cooling inside the refrigerator. Let us look at the video that shows leveling the refrigerator feet.
We need to support the refrigerator using woodblock or shim to level the leg. Then, turn the leveling screw using a ratchet to adjust the height of the leg. If the leveling leg is damaged, we need to install the new leg.
The maintenance tasks to be carried out every six months is as follows:
Change the water filter, and
Clean the drain pan and drain hole
Let us take a look at each of them.
Every six months, we should replace the water filter on our refrigerator. This helps ensure that the water and ice dispensed through the dispenser are clean and odor-free. We will look into step by step process for replacing the water filter in the latter topic.
Recall that water drains through the drain hole. The food debris can be forced into the drain line, or water draining away from the food compartment can freeze the drain line. We should pour a warm solution of tap water and vinegar through the line to free up the line.
A cracked or split drain pan can lead to water leaks. We need to clean the pan thoroughly and check for cracks or splits. We should replace the damaged pan. The maintenance tasks to be carried out every five years are as follows:
Clean the water lines,
Inspection of wiring, and
Replace the fans
Let us take a look at each of them.
The tubes that lead to the fridge from the water supply line can get dirty and clogged over time. The internal tubing through the water filter, ice maker, and water dispenser can need cleaning.
We should clean these tubes with a mild non-toxic solution like vinegar. This kills any mold living in the water lines and will reveal any clogs. If the water line is damaged, we need to replace it. Let us look at the video that shows how to change water lines.
We will first have to unplug the refrigerator and turn the water valve off. Then we need to remove one end of the water line from the water valve from the back of the refrigerator. Remove the other end from the water filter assembly.
The water line is then taken out and cleaned with a solution of 1 cup of vinegar per gallon of water. Flush water through the water line multiple times. Then, we need to reconnect the tubes by pushing them until they fit inside.
Once the lines are completely fit inside the filter head, we need to lock them using the locking collar. This will ensure the water line doesn’t come out. If the water line is damaged, we need to replace it.
Over time, the wire casing or the copper wires can get damaged. The damaged insulation could cause a short circuit, leading to arcing or fire. The periodic inspection of our fridge wiring will ensure that there are no electrical hazards.
Every five years, along with the wiring, inspect the condenser fan and evaporator fan. If the fan is performing poorly, get them replaced. We will look into step by step process of how to replace the fan in the latter topic.
Along with the maintenance tasks, we perform few operational checks regularly to ensure that the system works properly. These include ensuring:
the system is operating safely, and
the electricity bills are efficient and optimal
The refrigerator owner performs the operational checks. The operation checks and routine maintenance ensure the prolonged life of the refrigerator.
We perform routine maintenance of the refrigerator regularly to ensure that the system works properly.
Before starting the maintenance of the refrigerator, we should follow some safety precautions. These include:
Turn OFF the refrigerator, and
Wear safety gloves.
We schedule the periodic maintenance after specific time intervals. Along with the periodic maintenance tasks, we perform few operational checks to ensure that the system works properly.
Maintenance and Troubleshooting: Wiring Diagrams
In this module, we will review wiring diagrams. We will learn how to use a wiring diagram to troubleshoot a system. Skip to quiz!
Overview
Recall that a wiring diagram is a blueprint of an electrical system. Wiring diagrams display:
The components in a system,
The wiring, and
The flow of current
There are different symbols for each component of the refrigerator. As the system gets more and more complex, it gets hard to remember each of these symbols. For this reason, some of the wiring diagrams come with a legend.
The legend identifies which symbols are used and what they represent. The legend does not explain what every symbol means.
Troubleshooting
The wiring diagram is often used for troubleshooting the electrical and control system of the refrigerator. Most refrigerators and freezers have wiring diagrams printed to the back. If they are not present, we can get them in the service manual provided by the manufacturer or on the internet.
In the picture to the right, you can see a schematic diagram of a domestic refrigerator. The lines represent wires that connect electrical components in the appliance. We need to follow the wires to troubleshoot our appliance.
When we are troubleshooting an electrical problem in an appliance, a multimeter is an essential tool. For example, if the component inside the refrigerator isn’t working, a break in the wires may be one of the causes. Checking continuity allows us to test whether current is making it all the way through a wire.
When you measure continuity, the meter will display either:
“OL”
A low number and a beep sound
See the picture to the right. In the picture, we are checking the continuity of a light switch.
Recall that if the multimeter reads “OL,” the component or wire you are checking does not have continuity. If your multimeter reads a low value and emits a beep sound, then the component you checked has continuity.
The wiring diagram is often used for troubleshooting the electrical and control system of the refrigerator. The wiring diagram will show you the components in a system and how they are wired.
When we are troubleshooting an electrical problem in an appliance, a multimeter is an essential tool.
Refrigerator Troubleshooting: Primary Components
In this module, we will discuss the common refrigerator problems associated with primary components. We will also learn how to fix these problems. Skip to quiz!
Diagnosing malfunctions
Refrigerators can last for many years without any major faults or damages if we perform periodic maintenance. However, if proper care is not taken, they can start showing signs of trouble and may need repairs.
Some of the common signs of trouble are:
The refrigerator is making unusual noises
Items inside the refrigerator don’t remain as cool as they used to
Water in the fridge
Water under the fridge
Refrigerator lights not working
Some of the common signs of trouble are:
Fridge not defrosting
Water dispenser not working
Ice maker is overflowing
The temperature in the freezer section is higher than normal
There are underlying causes for the signs of the trouble of the refrigerator. These causes are due to faults in the individual system such as:
Primary and secondary components,
Dispenser system,
Defrost system,
Electrical system, and
Control system
Some refrigerator models have diagnostic test modes in them to detect the cause of the problem. The test mode allows us to diagnose the malfunction inside the refrigerator. However, the method of activating diagnostic test mode varies from model to model.
The method of activating diagnostic test mode varies from model to model. We can find the information to enter the test mode in the tech sheet provided by the manufacturer. The sheet is usually located behind the bottom front grill or taped to the back of the refrigerator.
The refrigerator runs through several tests to diagnose a problem. We will need to unplug our refrigerator from the power outlet for at least 30 seconds to exit the test mode. Once we plug it back in, our refrigerator will have exited diagnostic mode.
Since we use the refrigerator every day, we need to get it repaired or serviced as soon as any problem is detected.
The primary components of the refrigerator that may get malfunctioned and need troubleshooting are:
Compressor,
Condenser, and
Thermostat
Let us discuss signs of trouble that occur due to these components and how to troubleshoot them.
Compressor
The typical complaints associated with failure of the compressor are:
The refrigerator temperature is warm.
The freezer temperature is warm.
The refrigerator does not run at all.
Food is spoiling.
The compressor may fail to run because of:
No power supply
Faulty start relay
Faulty thermistor
The electronic control board has gone bad
Possible broken wires
If the fridge is not cooling, the compressor doesn't get power. We need to first check for the power button. Make sure the refrigerator light is on. This will ensure that compressor is getting power.
Recall that the control board sends a control signal to the fan relay by default when the compressor starts. The fan relay then starts the fan motor. So, another way to ensure that compressor is getting power is by checking the condenser fan or evaporator fan.
If the condenser or evaporator fan runs, the compressor is also getting power. This is because the compressor shares a circuit with the condenser and evaporator fan motor on most refrigerators. The video shows how to ensure that compressor is getting power.
How to Inspect Relays
Recall that the relay supplies electricity to a secondary winding of the compressor motor to give it extra starting torque. If the relay is faulty, then the compressor won't run. Next, we should check the start relay.
The troubleshooting for relay differs according to the type of relay used. The types of relay we usually find on the refrigerator are:
Separate relay, and
Combination relay
Recall that overload protects the motor from overheating and winding damage. The separate relay type has a separate overload protector, whereas the combination has a built-in overload on the bottom side of the relay.
To troubleshoot these relays, we use three methods:
Rattle test,
Continuity test using a multimeter, and
Resistance test using a multimeter
Let us take a look at each of them.
Before starting troubleshooting of relay, we need to remove it from the refrigerator. Recall that it is located at the backside of the refrigerator.
For safety, unplug the refrigerator. Unhook the retainer clip and pull the start relay out of the refrigerator.
For the rattle test, we need to shake the start relay. Depending on the output sound, we can decide the relay is good or bad. Let us look at the video of the rattle test.
The overload will always have a slight rattle to it. Since the combination relays always have an overload built into them, they constantly rattle. The separate relay used in the older refrigerator always rattle, whereas the other one does not rattle if it works fine.
If the rattle test does not give the correct result, check for continuity. Recall that the perpendicular terminal will be the “outlet” of the relay, and the center of the remaining three terminals will be the “inlet.” The other two are the control pins.
For measuring continuity, we need to connect multimeter leads into control pins of the relay. If the multimeter beeps, the relay is good.
If the relay is faulty, the multimeter will read 0L or 1 in the far left digit. If the start relay is working correctly, we may have a defective compressor.
We can also perform a resistance test by setting the multimeter to the Ω setting. The multimeter should give close to 5Ω resistance for a good relay. If the relay is bad, the multimeter will give no reading or very high resistance reading.
Other Causes of Compressor Malfunction
The compressor may also not work if we have a defective:
Electronic control board, and
Temperature sensor.
We can run the diagnostic test mode to ensure our compressor is running fine before diagnosing these components.
Recall that the control board receives input from temperature sensors to operate the compressor. A bad thermistor does not send a signal to the control board. This prevents the compressor from running in normal operating mode.
The diagnostic test mode forces the compressor to run whether the thermistor is broken or not. If the compressor starts in the diagnostic test mode, we need to replace the thermistor.
If the compressor doesn't run in the diagnostic test mode, the thermistor is working fine. The only possible cause of compressor malfunction is a break in the control board wiring or a bad control board. We can then check continuity from the electronic control board through the compressor circuit.
If the compressor circuit is open, we will get an OL or 1 in the far left digit on the multimeter. This means the compressor is not getting power.
We need to then look for pinched or broken wires in the control board harness and on the wires leading up to the compressor. We should repair or replace all the broken wires in the circuit. If no broken wires are present, we should check continuity from the control board to the compressor.
A reading of about 5 ohms indicates continuity in the compressor circuit. If we get the continuity in the circuit, then the cause of the compressor not getting power is a faulty electronic control board. This is because the board isn’t sending voltage through the circuit to the compressor.
The common problems in the refrigerator are due to a fault in the individual systems. Some refrigerator models have diagnostic test modes in them to detect the cause of the problem.
The primary components of the refrigerator that may get malfunctioned and need troubleshooting are:
Compressor,
Condenser, and
Thermostat
We will go over the condenser and thermostat troubleshooting in the next topic.
Refrigerator Troubleshooting: Primary Components
In this module, we will discuss the common refrigerator problems associated with primary components. We will also learn how to fix these problems. Skip to quiz!
Condenser
The complaints associated with bad condenser coil are:
Overheating of the compressor, and
The refrigerator is too warm
Recall that the dirt on the condenser coil acts as an insulator and does not allow the heat to dissipate. This causes improper cooling of the refrigerant. This leads to improper cooling of the refrigerator.
Dirty condenser coils cause the compressor to overheat. Overheating causes the compressor to stop working, and the entire refrigeration process stops as well. We need to dust the coils to troubleshoot these issues.
Thermostat
Recall that the ideal temperature in the refrigerator for keeping food and drinks cold is between 32℉ to 40℉. The thermostat plays a vital role in maintaining this temperature inside your refrigerator. If we suddenly notice that food isn’t as cool as expected, then a faulty thermostat can be a reason.
The common signs that indicate our fridge is suffering from a faulty thermostat are:
The fridge is not cool enough,
The fridge is getting unusually cold, and
Fluctuation in the fridge inside temperature
If the fridge is not cool enough, the food can get spoilt. The food can get frozen if the fridge is getting unusually cold. To avoid these problems, we need to troubleshoot the thermostat.
For troubleshooting the thermostat, unplug the refrigerator. Next, locate the thermostat dial. The thermostat is located directly behind the dial.
Then, we should remove the plastic cover that protects the thermostat and its controls. Some covers are screwed into place, while others are held in place by plastic clips. Depending on our make and model refrigerator, we may have to remove the dial before taking the cover off.
Next, we should remove the two wires on the thermostat. Set the multimeter to continuity setting. Then, touch both the multimeter probes to one terminal on the thermostat. If the multimeter beeps, the thermostat is working fine.
Now we should check resistance across the two terminals of the thermostat. Set the multimeter to Ω setting. Then, touch one of the multimeter probes to one terminal on the thermostat and the other probe to the other terminal.
The multimeter will read 0L or 1 in the far left digit when the thermostat dial is OFF. Next, rotate the thermometer dial and check the resistance. The multimeter should display some resistance value when the thermometer is ON. Let us look at the video that shows this.
If the thermostat is not working correctly, we need to replace it. Let us look at the video that shows how to replace a thermostat.
The panel behind the thermostat knob is opened. Then all the wires and clips on the thermostat are removed. Before removing the wires taking a picture of a wired thermostat helps while installing a new one.
The complaints associated with bad condenser coil are:
Overheating of the compressor, and
The refrigerator is too warm
We need to dust the coils to troubleshoot these issues.
The common signs that indicate our fridge is suffering from a faulty thermostat are:
The fridge is not cool enough,
The fridge is getting unusually cold, and
Fluctuation in the fridge inside temperature
We check the continuity of the thermostat to troubleshoot it.
Question #1: What is the time interval for routine maintenance of the refrigerator?
Every leap year
Every three days
Every week
Every six month
Scroll down for the answer...
Answer: Every six month
We schedule the time-based maintenance after specific time intervals.
These include:
Monthly maintenance,
Every three months,
Every six months, and
Every five year
Question #2: What maintenance tasks are to be carried out every month for the routine maintenance of the refrigerator? (select all that apply)
Ensuring the vents are clear
Replacing filter
Throwing away old foods
Cleaning the refrigerator
Scroll down for the answer...
Answer: Ensuring the vents are clear
Throwing away old foods
Cleaning the refrigerator
The maintenance tasks to be carried out every month is as follows:
Cleaning the refrigerator,
Throwing away old foods, and
Ensuring the vents are clear
Question #3: What maintenance tasks are to be carried out every three months for the routine maintenance of the refrigerator? (select all that apply)
Dust the condenser coils
Grease the gasket
Replace fans
Level the feet of the refrigerator
Scroll down for the answer...
Answer: Dust the condenser coils
Grease the gasket
Level the feet of the refrigerator
The maintenance tasks to be carried out every three months is as follows:
Dust the condenser coils,
Grease the gasket, and
Level the feet
Question #4: Why do we need to replace the water filter on our refrigerator dispenser every six months? (select all that apply)
To improve humidity of the air
To ensure no contamination of ice and water
To make the process of ice making faster
To improve the cooling efficiency of the refrigerator
Scroll down for the answer...
Answer: To ensure no contamination of ice and water
Every six months, we should replace the water filter on our refrigerator. This helps ensure that the water and ice dispensed through the dispenser are clean and odor-free.
Question #5: We need to clean the refrigerator water lines every six months.
False
True
Scroll down for the answer...
Answer: False
False.
We need to clean the refrigerator water lines every five years.
Question #6: What operation checks do we perform on the refrigerator? (select all that apply)
The electricity bills are efficient and optimal
No frost over the condenser coil
The system is operating safely
Defrost cycle is making sure ice build-up on evaporator
Scroll down for the answer...
Answer: The electricity bills are efficient and optimal
The system is operating safely
We perform few operational checks to ensure that the system works properly.
These include ensuring:
the system is operating safely, and
the electricity bills are efficient and optimal
Question #7: Where does the wiring diagram of any HVAC system display?
The components in a system
Size of the components in the system
Material of the components
The wiring
Scroll down for the answer...
Answer: The components in a system
The wiring
Wiring diagrams display:
The components in a system,
The wiring, and
The flow of current
Question #8: What is the purpose of legend in the wiring diagram?
To identify the size of the components
To identify symbols of the components and what they represent.
To show the material of the components
To display voltage and current
Scroll down for the answer...
Answer: To identify symbols of the components and what they represent.
The legend identifies which symbols are used and what they represent. The legend does not explain what every symbol means.
Question #9: How do we troubleshoot an electrical problem in the domestic refrigerator?
Using grease gun
Using thermometer
Using a multimeter
Using a calculator
Scroll down for the answer...
Answer: Using thermometer
The legend identifies which symbols are used and what they represent. The legend does not explain what every symbol means.
Question #10: Which of the following is a common problem in the refrigerator? (Select all that apply)
Water under the fridge
Fridge not defrosting
Refrigerator burning food kept inside
The refrigerator is making unusual noises
Scroll down for the answer...
Answer: Water under the fridge
Fridge not defrosting
The refrigerator is making unusual noises
Some of the common problems in the refrigerator are:
The refrigerator is making unusual noises
Water in the fridge
Water under the fridge
Fridge not defrosting
Question #11: How does the refrigerator come out of the diagnostic test mode?
By turning off the ice maker power
By changing the temperature of the thermostat
By unplugging the refrigerator power
By opening the refrigerator door
Scroll down for the answer...
Answer: By unplugging the refrigerator power
We will need to unplug our refrigerator from the power outlet for at least 30 seconds to exit the test mode.
Question #12: What are the problems associated with a faulty compressor of the refrigerator? (select all that apply)
The refrigerator temperature is warm.
Fridge not defrosting
The refrigerator does not run at all.
Ice maker is overflowing
Scroll down for the answer...
Answer: The refrigerator temperature is warm.
The refrigerator does not run at all.
The typical complaints associated with failure of the compressor are:
The refrigerator temperature is warm.
The freezer temperature is warm.
The refrigerator does not run at all.
Question #13: Why does the refrigerator compressor fail to run? (select all that apply)
Faulty electronic control board
Faulty thermistor
Faulty defrost heater
Faulty start relay
Scroll down for the answer...
Answer: Faulty electronic control board
Faulty thermistor
Faulty start relay
The compressor may fail to run because of:
Faulty start relay
Faulty thermistor
Faulty electronic control board
Possible broken wires
Question #14: What are the methods to troubleshoot faulty compressor start relay? (select all that apply)
Rattle test
Nitrogen purging
Continuity test using a multimeter
Resistance test using a multimeter
Scroll down for the answer...
Answer: Rattle test
Continuity test using a multimeter
Resistance test using a multimeter
To troubleshoot relays, we use three methods:
Rattle test,
Continuity test using a multimeter, and
Resistance test using a multimeter
Question #15: What are the problems associated with a dusty condenser coil of the refrigerator? (select all that apply)
The refrigerator temperature is warm.
Fridge not defrosting
Overheating of the compressor
Ice maker is overflowing
Scroll down for the answer...
Answer: The refrigerator temperature is warm.
Overheating of the compressor
The typical complaints associated with bad condenser coil are:
Overheating of the compressor, and
The refrigerator is too warm
Question #16: What are the problems associated with a faulty thermostat of the refrigerator? (select all that apply)
The fridge is not cool enough
Fridge not defrosting
Fluctuation in the fridge inside temperature
Ice maker is overflowing
Scroll down for the answer...
Answer: The fridge is not cool enough
Fluctuation in the fridge inside temperature
The common problems because of a faulty thermostat are:
The fridge is not cool enough,
The fridge is getting unusually cold, and
Fluctuation in the fridge inside temperature
’Question #17: How do we troubleshoot the refrigerator thermostat?
By rotating the thermostat knob twice
By checking resistance across the two terminals of the thermostat
Using rattle test
By calibrating with ice maker thermostat temperature
Scroll down for the answer...
Answer: By checking resistance across the two terminals of the thermostat
We should check resistance across the two terminals of the thermostat to troubleshoot it.