Louisiana (LA) Mechanical
Contractor Exam Questions
And Correct
Answers (Verified Answers)
Plus Rationales 2025 Q&A
| Instant Download Pdf
1. What is the primary purpose of the International
Mechanical Code (IMC)?
A. Electrical safety regulation
B. Plumbing fixture sizing
C. Mechanical system installation standards
D. Fire alarm wiring
Answer: C
Rationale: The IMC establishes minimum standards for the
design, installation, and maintenance of mechanical
systems such as HVAC.
2. Which refrigerant is considered an HFC commonly used in
modern HVAC systems?
,A. R-22
B. R-410A
C. Ammonia
D. R-12
Answer: B
Rationale: R-410A is an HFC refrigerant widely used as a
replacement for R-22.
3. What does CFM measure in HVAC systems?
A. Pressure
B. Air velocity
C. Airflow volume
D. Temperature difference
Answer: C
Rationale: CFM (Cubic Feet per Minute) measures the
volume of air moved.
4. Which tool is used to measure refrigerant pressure?
A. Thermometer
B. Manifold gauge set
C. Psychrometer
D. Anemometer
Answer: B
Rationale: A manifold gauge set measures high and low side
refrigerant pressures.
,5. What is the standard voltage for residential HVAC
systems in the U.S.?
A. 120V only
B. 240V only
C. 120/240V split-phase
D. 480V
Answer: C
Rationale: Residential systems typically use 120/240V split-
phase power.
6. What is superheat in a refrigeration system?
A. Liquid refrigerant temperature
B. Gas above boiling point temperature
C. Compressor discharge pressure
D. Condenser coil temperature
Answer: B
Rationale: Superheat is the temperature of refrigerant
vapor above its boiling point.
7. Which component removes moisture and debris from a
refrigeration system?
A. Compressor
B. Filter drier
C. Expansion valve
D. Evaporator
, Answer: B
Rationale: A filter drier removes moisture and contaminants
from refrigerant.
8. What is the function of a compressor in an HVAC system?
A. Expand refrigerant
B. Cool air
C. Circulate and compress refrigerant
D. Filter air
Answer: C
Rationale: The compressor increases refrigerant pressure
and circulates it through the system.
9. Which gas is commonly used for leak testing HVAC
systems?
A. Oxygen
B. Nitrogen
C. Carbon dioxide
D. Helium only
Answer: B
Rationale: Dry nitrogen is commonly used for pressure
testing and leak detection.
10. What does BTU measure?
Contractor Exam Questions
And Correct
Answers (Verified Answers)
Plus Rationales 2025 Q&A
| Instant Download Pdf
1. What is the primary purpose of the International
Mechanical Code (IMC)?
A. Electrical safety regulation
B. Plumbing fixture sizing
C. Mechanical system installation standards
D. Fire alarm wiring
Answer: C
Rationale: The IMC establishes minimum standards for the
design, installation, and maintenance of mechanical
systems such as HVAC.
2. Which refrigerant is considered an HFC commonly used in
modern HVAC systems?
,A. R-22
B. R-410A
C. Ammonia
D. R-12
Answer: B
Rationale: R-410A is an HFC refrigerant widely used as a
replacement for R-22.
3. What does CFM measure in HVAC systems?
A. Pressure
B. Air velocity
C. Airflow volume
D. Temperature difference
Answer: C
Rationale: CFM (Cubic Feet per Minute) measures the
volume of air moved.
4. Which tool is used to measure refrigerant pressure?
A. Thermometer
B. Manifold gauge set
C. Psychrometer
D. Anemometer
Answer: B
Rationale: A manifold gauge set measures high and low side
refrigerant pressures.
,5. What is the standard voltage for residential HVAC
systems in the U.S.?
A. 120V only
B. 240V only
C. 120/240V split-phase
D. 480V
Answer: C
Rationale: Residential systems typically use 120/240V split-
phase power.
6. What is superheat in a refrigeration system?
A. Liquid refrigerant temperature
B. Gas above boiling point temperature
C. Compressor discharge pressure
D. Condenser coil temperature
Answer: B
Rationale: Superheat is the temperature of refrigerant
vapor above its boiling point.
7. Which component removes moisture and debris from a
refrigeration system?
A. Compressor
B. Filter drier
C. Expansion valve
D. Evaporator
, Answer: B
Rationale: A filter drier removes moisture and contaminants
from refrigerant.
8. What is the function of a compressor in an HVAC system?
A. Expand refrigerant
B. Cool air
C. Circulate and compress refrigerant
D. Filter air
Answer: C
Rationale: The compressor increases refrigerant pressure
and circulates it through the system.
9. Which gas is commonly used for leak testing HVAC
systems?
A. Oxygen
B. Nitrogen
C. Carbon dioxide
D. Helium only
Answer: B
Rationale: Dry nitrogen is commonly used for pressure
testing and leak detection.
10. What does BTU measure?
