NATE Core Service Certification Exam
Practice Test Questions And Correct
Answers (Verified Answers) Plus
Rationales 2026 Q&A Instant Download
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1. What is the primary function of a thermostat in an HVAC system?
A. To circulate air through the ductwork
B. To regulate the temperature of the space
C. To remove moisture from the air
D. To provide electrical power to the system
Rationale: The thermostat monitors the temperature and signals the
HVAC system to turn on or off to maintain the desired temperature.
2. What type of refrigerant is commonly used in new residential air
conditioning systems?
A. R-12
B. R-410A
C. R-22
D. R-134a
Rationale: R-410A is widely used in modern residential AC systems due to
its efficiency and ozone-safe properties.
3. Which safety device protects against overcurrent in an HVAC system?
A. Thermostat
, B. Contactor
C. Circuit breaker
D. Expansion valve
Rationale: A circuit breaker interrupts electrical flow if current exceeds
safe levels, preventing damage and fire hazards.
4. What is the primary purpose of the evaporator coil in a cooling system?
A. To compress refrigerant
B. To absorb heat from indoor air
C. To discharge air outdoors
D. To filter dust from the air
Rationale: The evaporator coil allows refrigerant to absorb heat from
indoor air, cooling the space.
5. Which component of an air conditioning system changes refrigerant from a
low-pressure gas to a high-pressure liquid?
A. Evaporator coil
B. Compressor
C. Expansion valve
D. Condenser coil
Rationale: The compressor raises the pressure and temperature of the
refrigerant to prepare it for heat rejection in the condenser coil.
6. What is the recommended minimum clearance around an outdoor
condenser unit?
A. 6 inches
B. 12 inches
C. 18 inches
D. 24 inches
Rationale: A 24-inch clearance allows proper airflow for efficient heat
transfer and prevents obstructions.
7. What is the purpose of the expansion device in a refrigeration cycle?
A. To compress refrigerant
B. To reduce refrigerant pressure and control flow into the evaporator
, C. To remove heat from the condenser
D. To filter refrigerant
Rationale: The expansion device meters refrigerant into the evaporator at
a lower pressure, allowing it to absorb heat efficiently.
8. Which type of heat pump uses the outside air as a heat source?
A. Geothermal heat pump
B. Air-source heat pump
C. Water-source heat pump
D. Electric furnace
Rationale: Air-source heat pumps extract heat from outdoor air to provide
heating, even in cold temperatures.
9. What is the function of a contactor in an HVAC system?
A. To measure temperature
B. To filter air
C. To control the flow of electrical power to components
D. To expand refrigerant
Rationale: The contactor acts as a relay, switching high-voltage power to
the compressor and condenser fan motor.
10.Which tool is used to measure refrigerant pressure?
A. Multimeter
B. Manifold gauge set
C. Thermometer
D. Clamp meter
Rationale: A manifold gauge set allows technicians to measure high- and
low-side refrigerant pressures accurately.
11.What is the typical voltage for residential HVAC systems in the U.S.?
A. 110/120 V for most controls, 220/240 V for compressors
B. 120 V for controls, 240 V for compressors
C. 208 V for all components
D. 480 V for all components
Practice Test Questions And Correct
Answers (Verified Answers) Plus
Rationales 2026 Q&A Instant Download
1. What is the primary function of a thermostat in an HVAC system?
A. To circulate air through the ductwork
B. To regulate the temperature of the space
C. To remove moisture from the air
D. To provide electrical power to the system
Rationale: The thermostat monitors the temperature and signals the
HVAC system to turn on or off to maintain the desired temperature.
2. What type of refrigerant is commonly used in new residential air
conditioning systems?
A. R-12
B. R-410A
C. R-22
D. R-134a
Rationale: R-410A is widely used in modern residential AC systems due to
its efficiency and ozone-safe properties.
3. Which safety device protects against overcurrent in an HVAC system?
A. Thermostat
, B. Contactor
C. Circuit breaker
D. Expansion valve
Rationale: A circuit breaker interrupts electrical flow if current exceeds
safe levels, preventing damage and fire hazards.
4. What is the primary purpose of the evaporator coil in a cooling system?
A. To compress refrigerant
B. To absorb heat from indoor air
C. To discharge air outdoors
D. To filter dust from the air
Rationale: The evaporator coil allows refrigerant to absorb heat from
indoor air, cooling the space.
5. Which component of an air conditioning system changes refrigerant from a
low-pressure gas to a high-pressure liquid?
A. Evaporator coil
B. Compressor
C. Expansion valve
D. Condenser coil
Rationale: The compressor raises the pressure and temperature of the
refrigerant to prepare it for heat rejection in the condenser coil.
6. What is the recommended minimum clearance around an outdoor
condenser unit?
A. 6 inches
B. 12 inches
C. 18 inches
D. 24 inches
Rationale: A 24-inch clearance allows proper airflow for efficient heat
transfer and prevents obstructions.
7. What is the purpose of the expansion device in a refrigeration cycle?
A. To compress refrigerant
B. To reduce refrigerant pressure and control flow into the evaporator
, C. To remove heat from the condenser
D. To filter refrigerant
Rationale: The expansion device meters refrigerant into the evaporator at
a lower pressure, allowing it to absorb heat efficiently.
8. Which type of heat pump uses the outside air as a heat source?
A. Geothermal heat pump
B. Air-source heat pump
C. Water-source heat pump
D. Electric furnace
Rationale: Air-source heat pumps extract heat from outdoor air to provide
heating, even in cold temperatures.
9. What is the function of a contactor in an HVAC system?
A. To measure temperature
B. To filter air
C. To control the flow of electrical power to components
D. To expand refrigerant
Rationale: The contactor acts as a relay, switching high-voltage power to
the compressor and condenser fan motor.
10.Which tool is used to measure refrigerant pressure?
A. Multimeter
B. Manifold gauge set
C. Thermometer
D. Clamp meter
Rationale: A manifold gauge set allows technicians to measure high- and
low-side refrigerant pressures accurately.
11.What is the typical voltage for residential HVAC systems in the U.S.?
A. 110/120 V for most controls, 220/240 V for compressors
B. 120 V for controls, 240 V for compressors
C. 208 V for all components
D. 480 V for all components
