NATE Core Service Certification Exam
Questions With Correct Answers (Verified
Answers) Plus Rationales 2026 Q&A | Instant
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1. Which of the following is the primary purpose of a heat exchanger
in an HVAC system?
A. Increase system airflow
B. Transfer heat between two fluids
C. Remove moisture from the air
D. Reduce refrigerant pressure
B. Transfer heat between two fluids
Rationale: A heat exchanger allows heat to move from one fluid (such
as air or water) to another without mixing the fluids, which is
essential for heating or cooling processes.
2. What is the function of a thermostat in a residential HVAC system?
A. Circulate refrigerant
B. Control system temperature
, C. Measure airflow velocity
D. Filter contaminants
B. Control system temperature
Rationale: A thermostat monitors indoor temperature and signals the
HVAC system to turn on or off to maintain the desired setpoint.
3. Which type of refrigerant is considered an HFC
(hydrofluorocarbon)?
A. R-22
B. R-134a
C. R-11
D. Ammonia
B. R-134a
Rationale: HFC refrigerants, like R-134a, do not contain chlorine and
are used as replacements for ozone-depleting CFCs and HCFCs.
4. What does SEER stand for in HVAC systems?
A. Seasonal Energy Efficiency Ratio
B. Standard Electric Energy Requirement
C. System Environmental Efficiency Rating
D. Safety Energy Evaluation Report
,A. Seasonal Energy Efficiency Ratio
Rationale: SEER measures the efficiency of air conditioners over an
entire cooling season. Higher SEER values indicate greater efficiency.
5. Which tool is used to measure refrigerant pressure in a system?
A. Thermometer
B. Multimeter
C. Manifold gauge set
D. Anemometer
C. Manifold gauge set
Rationale: A manifold gauge set is essential for measuring high and
low-side pressures, charging refrigerant, and diagnosing system
performance.
6. What is the primary safety concern when working with ammonia
refrigerant?
A. Toxicity
B. Electrical shock
C. High flammability
D. UV radiation
A. Toxicity
Rationale: Ammonia is highly toxic and can cause severe respiratory
irritation. Proper protective equipment is required.
, 7. Which component in a split system removes heat from indoor air?
A. Condenser coil
B. Evaporator coil
C. Expansion valve
D. Compressor
B. Evaporator coil
Rationale: The evaporator coil absorbs heat from the indoor air,
allowing the system to cool the space.
8. What is the function of the compressor in a refrigeration cycle?
A. Lower refrigerant pressure
B. Increase refrigerant pressure
C. Condense refrigerant
D. Filter moisture
B. Increase refrigerant pressure
Rationale: The compressor raises refrigerant pressure and
temperature, enabling heat rejection in the condenser.
9. Which of the following is an example of preventive maintenance
for an HVAC system?
A. Replacing a broken blower motor
B. Cleaning air filters and coils
Questions With Correct Answers (Verified
Answers) Plus Rationales 2026 Q&A | Instant
Download Pdf
1. Which of the following is the primary purpose of a heat exchanger
in an HVAC system?
A. Increase system airflow
B. Transfer heat between two fluids
C. Remove moisture from the air
D. Reduce refrigerant pressure
B. Transfer heat between two fluids
Rationale: A heat exchanger allows heat to move from one fluid (such
as air or water) to another without mixing the fluids, which is
essential for heating or cooling processes.
2. What is the function of a thermostat in a residential HVAC system?
A. Circulate refrigerant
B. Control system temperature
, C. Measure airflow velocity
D. Filter contaminants
B. Control system temperature
Rationale: A thermostat monitors indoor temperature and signals the
HVAC system to turn on or off to maintain the desired setpoint.
3. Which type of refrigerant is considered an HFC
(hydrofluorocarbon)?
A. R-22
B. R-134a
C. R-11
D. Ammonia
B. R-134a
Rationale: HFC refrigerants, like R-134a, do not contain chlorine and
are used as replacements for ozone-depleting CFCs and HCFCs.
4. What does SEER stand for in HVAC systems?
A. Seasonal Energy Efficiency Ratio
B. Standard Electric Energy Requirement
C. System Environmental Efficiency Rating
D. Safety Energy Evaluation Report
,A. Seasonal Energy Efficiency Ratio
Rationale: SEER measures the efficiency of air conditioners over an
entire cooling season. Higher SEER values indicate greater efficiency.
5. Which tool is used to measure refrigerant pressure in a system?
A. Thermometer
B. Multimeter
C. Manifold gauge set
D. Anemometer
C. Manifold gauge set
Rationale: A manifold gauge set is essential for measuring high and
low-side pressures, charging refrigerant, and diagnosing system
performance.
6. What is the primary safety concern when working with ammonia
refrigerant?
A. Toxicity
B. Electrical shock
C. High flammability
D. UV radiation
A. Toxicity
Rationale: Ammonia is highly toxic and can cause severe respiratory
irritation. Proper protective equipment is required.
, 7. Which component in a split system removes heat from indoor air?
A. Condenser coil
B. Evaporator coil
C. Expansion valve
D. Compressor
B. Evaporator coil
Rationale: The evaporator coil absorbs heat from the indoor air,
allowing the system to cool the space.
8. What is the function of the compressor in a refrigeration cycle?
A. Lower refrigerant pressure
B. Increase refrigerant pressure
C. Condense refrigerant
D. Filter moisture
B. Increase refrigerant pressure
Rationale: The compressor raises refrigerant pressure and
temperature, enabling heat rejection in the condenser.
9. Which of the following is an example of preventive maintenance
for an HVAC system?
A. Replacing a broken blower motor
B. Cleaning air filters and coils
