This test is designed to help you prepare for the actual certification exam by assessing your knowledge of appliance repair, electrical systems, refrigeration, diagnostics, and safety protocols.
The test consists of 50 multiple-choice questions that cover a wide range of topics relevant to appliance service technicians.
Use this practice test to identify areas where you may need further study and to build confidence in your technical skills.
Good luck!
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Request InfoNational Appliance Service Technician Certification (NASTeC) practice test
Congratulations - you have completed National Appliance Service Technician Certification (NASTeC) practice test.
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Question 1 |
What is the primary purpose of a capacitor in an electric motor?
To store electrical energy | |
To regulate voltage | |
To start the motor and improve its efficiency | |
To reduce noise |
Question 2 |
Which of the following is a common symptom of a faulty thermal fuse in a dryer?
The dryer runs but does not heat | |
The dryer drum does not rotate | |
The dryer overheats | |
The dryer makes unusual noises |
Question 3 |
What is the recommended refrigerant for most modern household refrigerators?
R-22 | |
R-134a | |
R-410A | |
R-600a |
Question 4 |
Which tool is used to measure electrical resistance?
Multimeter | |
Clamp meter | |
Manifold gauge | |
Psychrometer |
Question 5 |
What is the function of a thermistor in a refrigerator?
To control the compressor | |
To monitor temperature and send signals to the control board | |
To defrost the evaporator coils | |
To regulate the fan speed |
Question 6 |
Which of the following is a safety precaution when working with refrigerants?
Wear insulated gloves | |
Work in a well-ventilated area | |
Use an open flame to detect leaks | |
Avoid using a manifold gauge set |
Question 7 |
What is the most likely cause of a washing machine that agitates but does not spin?
Faulty lid switch | |
Broken drive belt | |
Defective water inlet valve | |
Clogged drain pump |
Question 8 |
Which component is responsible for converting AC power to DC power in an appliance?
Transformer | |
Rectifier | |
Capacitor | |
Relay |
Question 9 |
What is the purpose of a defrost cycle in a refrigerator?
To cool the compressor | |
To prevent ice buildup on the evaporator coils | |
To increase energy efficiency | |
To clean the condenser coils |
Question 10 |
Which of the following is a symptom of a clogged condenser coil in a refrigerator?
The refrigerator runs continuously | |
The refrigerator is too cold | |
The compressor does not start | |
The evaporator fan is noisy |
Question 11 |
What is the primary function of a pressure switch in a gas dryer?
To regulate gas flow | |
To monitor drum rotation | |
To detect airflow and ensure proper venting | |
To control the heating element |
Question 12 |
Which of the following is a common cause of a dishwasher not draining properly?
Faulty heating element | |
Clogged drain hose | |
Defective door latch | |
Broken wash arm |
Question 13 |
What is the purpose of a bimetal thermostat in an appliance?
To measure humidity | |
To regulate temperature by opening and closing a circuit | |
To control water flow | |
To monitor pressure levels |
Question 14 |
Which of the following refrigerants is considered environmentally friendly?
R-22 | |
R-410A | |
R-134a | |
R-600a |
Question 15 |
What is the most likely cause of a refrigerator that runs but does not cool?
Faulty evaporator fan | |
Defective door gasket | |
Clogged air filter | |
Broken light bulb |
Question 16 |
Which tool is used to detect refrigerant leaks?
Manifold gauge | |
Electronic leak detector | |
Psychrometer | |
Clamp meter |
Question 17 |
What is the purpose of a start relay in a compressor?
To provide initial power to start the compressor | |
To regulate refrigerant flow | |
To control the defrost cycle | |
To monitor temperature |
Question 18 |
Which of the following is a common cause of a gas oven not heating?
Faulty igniter | |
Broken bake element | |
Defective thermostat | |
Clogged gas line |
Question 19 |
What is the function of a centrifugal switch in a motor?
To disconnect the start winding once the motor reaches a certain speed | |
To regulate voltage | |
To control the direction of rotation | |
To monitor temperature |
Question 20 |
Which of the following is a symptom of a faulty door switch in a dishwasher?
The dishwasher does not start | |
The dishwasher leaks water | |
The dishwasher does not drain | |
The dishwasher is noisy |
Question 21 |
What is the purpose of a condenser in a refrigeration system?
To absorb heat from the refrigerator interior | |
To release heat from the refrigerant | |
To compress the refrigerant | |
To regulate pressure |
Question 22 |
Which of the following is a common cause of a refrigerator making loud noises?
Faulty evaporator fan | |
Clogged drain line | |
Defective door gasket | |
Broken light bulb |
Question 23 |
What is the primary function of a compressor in a refrigeration system?
To absorb heat | |
To circulate refrigerant | |
To regulate temperature | |
To compress refrigerant gas |
Question 24 |
Which of the following is a common cause of a washing machine that leaks water?
Faulty water inlet valve | |
Broken drive belt | |
Clogged drain pump | |
Defective lid switch |
Question 25 |
What is the purpose of a defrost timer in a refrigerator?
To control the defrost cycle | |
To regulate compressor operation | |
To monitor temperature | |
To control fan speed |
Question 26 |
Which of the following is a symptom of a faulty igniter in a gas oven?
The oven does not heat | |
The oven overheats | |
The oven door does not close properly | |
The oven light does not work |
Question 27 |
What is the function of a run capacitor in an electric motor?
To improve motor efficiency during operation | |
To start the motor | |
To regulate voltage | |
To reduce noise |
Question 28 |
Which of the following is a common cause of a dishwasher not cleaning dishes properly?
Clogged spray arms | |
Faulty heating element | |
Defective door latch | |
Broken drain pump |
Question 29 |
What is the purpose of a high-pressure switch in a refrigeration system?
To protect the compressor from excessive pressure | |
To regulate refrigerant flow | |
To control the defrost cycle | |
To monitor temperature |
Question 30 |
Which of the following is a common cause of a refrigerator that cycles too frequently?
Dirty condenser coils | |
Faulty evaporator fan | |
Defective door gasket | |
Broken light bulb |
Question 31 |
What is the primary function of a thermocouple in a gas appliance?
To measure temperature | |
To detect the presence of a flame | |
To regulate gas flow | |
To control ignition |
Question 32 |
Which of the following is a common cause of a dryer not heating up?
Faulty heating element | |
Broken drive belt | |
Clogged lint filter | |
Defective door switch |
Question 33 |
What is the purpose of a suction line accumulator in a refrigeration system?
To store excess refrigerant | |
To prevent liquid refrigerant from entering the compressor | |
To regulate pressure | |
To absorb heat |
Question 34 |
Which of the following is a common cause of a washing machine that does not agitate?
Faulty lid switch | |
Broken drive belt | |
Clogged drain pump | |
Defective water inlet valve |
Question 35 |
What is the function of a reversing valve in a heat pump system?
To change the direction of refrigerant flow | |
To regulate pressure | |
To control the defrost cycle | |
To monitor temperature |
Question 36 |
Which of the following is a common cause of a refrigerator that freezes food?
Faulty thermostat | |
Clogged drain line | |
Defective door gasket | |
Broken light bulb |
Question 37 |
What is the purpose of a pressure relief valve in a water heater?
To release excess pressure | |
To regulate temperature | |
To control water flow | |
To monitor pressure |
Question 38 |
Which of the following is a common cause of a dishwasher not filling with water?
Faulty water inlet valve | |
Clogged spray arms | |
Defective door latch | |
Broken drain pump |
Question 39 |
What is the function of an evaporator in a refrigeration system?
To absorb heat from the refrigerator interior | |
To release heat from the refrigerant | |
To compress the refrigerant | |
To regulate pressure |
Question 40 |
Which of the following is a common cause of a dryer that takes too long to dry clothes?
Clogged vent | |
Faulty heating element | |
Broken drive belt | |
Defective door switch |
Question 41 |
What is the purpose of an overload protector in a compressor?
To protect the compressor from overheating | |
To regulate refrigerant flow | |
To control the defrost cycle | |
To monitor temperature |
Question 42 |
Which of the following is a common cause of a refrigerator that is too warm?
Faulty evaporator fan | |
Clogged drain line | |
Defective door gasket | |
Broken light bulb |
Question 43 |
What is the function of a condenser fan in a refrigeration system?
To cool the condenser coils | |
To circulate air inside the refrigerator | |
To compress the refrigerant | |
To regulate pressure |
Question 44 |
Which of the following is a common cause of a washing machine that does not spin?
Faulty lid switch | |
Broken drive belt | |
Clogged drain pump | |
Defective water inlet valve |
Question 45 |
What is the purpose of an expansion valve in a refrigeration system?
To regulate refrigerant flow | |
To absorb heat | |
To compress the refrigerant | |
To release heat |
Question 46 |
Which of the following is a common cause of a dishwasher that does not drain?
Clogged drain hose | |
Faulty heating element | |
Defective door latch | |
Broken wash arm |
Question 47 |
What is the function of a defrost heater in a refrigerator?
To melt ice on the evaporator coils | |
To regulate temperature | |
To control the compressor | |
To monitor pressure |
Question 48 |
Which of the following is a common cause of a gas oven that does not ignite?
Faulty igniter | |
Broken bake element | |
Defective thermostat | |
Clogged gas line |
Question 49 |
What is the purpose of a suction line in a refrigeration system?
To carry refrigerant from the evaporator to the compressor | |
To release heat from the refrigerant | |
To compress the refrigerant | |
To regulate pressure |
Question 50 |
Which of the following is a common cause of a refrigerator that makes a clicking noise?
Faulty start relay | |
Clogged drain line | |
Defective door gasket | |
Broken light bulb |
Once you are finished, click the button below. Any items you have not completed will be marked incorrect.
There are 50 questions to complete.
Read the full guide: How to Become an Appliance Repair Technician