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Missouri HVAC Contractor Exam
Practice Exam Questions And Correct
Answers (Verified Answers) Plus
Rationales 2026 Q&A Instant Download
Pdf
___________________________________________________________________
1. What is the primary purpose of a Manual J load calculation?
A. Determine duct insulation thickness
B. Size the HVAC equipment properly
C. Calculate refrigerant charge
D. Determine electrical demand
Answer: Size the HVAC equipment properly
Rationale: Manual J calculations determine heating and cooling loads to ensure
HVAC equipment is properly sized for the structure.
2. Which refrigerant has the highest ozone depletion potential?
A. R-410A
B. R-134a
C. R-22
D. R-32
Answer: R-22
,Rationale: R-22 is an HCFC refrigerant with ozone depletion potential and is
being phased out.
3. What device controls refrigerant flow into the evaporator?
A. Compressor
B. Condenser
C. Metering device
D. Accumulator
Answer: Metering device
Rationale: The metering device regulates refrigerant flow and pressure entering
the evaporator coil.
4. What is superheat?
A. Heat removed in the condenser
B. Temperature above refrigerant boiling point
C. Heat below saturation temperature
D. Condenser pressure drop
Answer: Temperature above refrigerant boiling point
Rationale: Superheat measures the temperature increase of refrigerant vapor
above its saturation temperature.
5. Which component removes heat from refrigerant vapor?
A. Evaporator
B. Compressor
C. Condenser
D. Expansion valve
Answer: Condenser
Rationale: The condenser rejects heat from refrigerant vapor to the surrounding
environment.
6. What is the standard voltage for most residential HVAC systems?
, A. 24 volts
B. 120 volts
C. 208 volts
D. 240 volts
Answer: 240 volts
Rationale: Most residential HVAC systems operate on 240-volt circuits for
compressors and motors.
7. Which instrument measures airflow in ducts?
A. Manometer
B. Hygrometer
C. Anemometer
D. Psychrometer
Answer: Anemometer
Rationale: An anemometer measures air velocity and airflow in HVAC systems.
8. What does a contactor do?
A. Measures pressure
B. Controls electrical power to equipment
C. Regulates refrigerant flow
D. Monitors humidity
Answer: Controls electrical power to equipment
Rationale: A contactor is an electrically controlled switch used to energize HVAC
components.
9. Which gas is commonly used for pressure testing HVAC lines?
A. Oxygen
B. Nitrogen
C. Propane
D. Acetylene
Missouri HVAC Contractor Exam
Practice Exam Questions And Correct
Answers (Verified Answers) Plus
Rationales 2026 Q&A Instant Download
___________________________________________________________________
1. What is the primary purpose of a Manual J load calculation?
A. Determine duct insulation thickness
B. Size the HVAC equipment properly
C. Calculate refrigerant charge
D. Determine electrical demand
Answer: Size the HVAC equipment properly
Rationale: Manual J calculations determine heating and cooling loads to ensure
HVAC equipment is properly sized for the structure.
2. Which refrigerant has the highest ozone depletion potential?
A. R-410A
B. R-134a
C. R-22
D. R-32
Answer: R-22
,Rationale: R-22 is an HCFC refrigerant with ozone depletion potential and is
being phased out.
3. What device controls refrigerant flow into the evaporator?
A. Compressor
B. Condenser
C. Metering device
D. Accumulator
Answer: Metering device
Rationale: The metering device regulates refrigerant flow and pressure entering
the evaporator coil.
4. What is superheat?
A. Heat removed in the condenser
B. Temperature above refrigerant boiling point
C. Heat below saturation temperature
D. Condenser pressure drop
Answer: Temperature above refrigerant boiling point
Rationale: Superheat measures the temperature increase of refrigerant vapor
above its saturation temperature.
5. Which component removes heat from refrigerant vapor?
A. Evaporator
B. Compressor
C. Condenser
D. Expansion valve
Answer: Condenser
Rationale: The condenser rejects heat from refrigerant vapor to the surrounding
environment.
6. What is the standard voltage for most residential HVAC systems?
, A. 24 volts
B. 120 volts
C. 208 volts
D. 240 volts
Answer: 240 volts
Rationale: Most residential HVAC systems operate on 240-volt circuits for
compressors and motors.
7. Which instrument measures airflow in ducts?
A. Manometer
B. Hygrometer
C. Anemometer
D. Psychrometer
Answer: Anemometer
Rationale: An anemometer measures air velocity and airflow in HVAC systems.
8. What does a contactor do?
A. Measures pressure
B. Controls electrical power to equipment
C. Regulates refrigerant flow
D. Monitors humidity
Answer: Controls electrical power to equipment
Rationale: A contactor is an electrically controlled switch used to energize HVAC
components.
9. Which gas is commonly used for pressure testing HVAC lines?
A. Oxygen
B. Nitrogen
C. Propane
D. Acetylene
