Practice Exam Questions And Correct

ASE A7 Heating & Air Conditioning Practice Exam Questions And Correct Answers (Verified Answers) Plus Rationales 2026 Q&A | Instant Download Pdf

• What is the main purpose of the expansion valve in an automotive A/C

system?

• Increase system pressure
• Filter refrigerant
• Regulate refrigerant flow into the evaporator
• Heat the refrigerant

Rationale: The expansion valve controls the flow of refrigerant into the

evaporator to maintain proper cooling and prevent evaporator freezing.

• Which refrigerant is most commonly used in modern automotive A/C

systems?

A. R-12 1 / 4

• R-134a

C. R-22

D. R-410A

Rationale: R-134a replaced R-12 due to environmental regulations and is

widely used in modern vehicles.

• What is the typical operating pressure of an R-134a system at 70°F

ambient temperature?

• 50–75 psi
• 90–120 psi
• 25–45 psi low side, 150–225 psi high side
• 10–20 psi

Rationale: R-134a systems operate at low-side pressures around 25–45 psi

and high-side pressures around 150–225 psi at moderate temperatures.

• What effect does a clogged condenser have on an A/C system?
• Reduces airflow in the cabin
• Increases high-side pressure and reduces cooling efficiency
• Increases low-side pressure
• Causes compressor over-speed

Rationale: A clogged condenser prevents proper heat dissipation, raising

high-side pressure and reducing overall cooling efficiency.

• Which component stores refrigerant and removes moisture from the

system?

• Evaporator 2 / 4

• Compressor
• Receiver/drier
• Condenser

Rationale: The receiver/drier stores liquid refrigerant and contains a

desiccant to remove moisture, protecting the system.

• Which is a sign of a refrigerant leak?
• Reduced engine power
• Excessive oil consumption
• Hissing sound near A/C components
• Brake pedal vibration

Rationale: Leaks in the A/C system often produce audible hissing or

bubbling noises and reduce cooling performance.

• What is the purpose of the compressor clutch?
• Regulate refrigerant pressure
• Engage and disengage the compressor as needed
• Filter the refrigerant
• Increase condenser efficiency

Rationale: The clutch allows the compressor to cycle on and off,

maintaining proper system operation and reducing wear.

• Why is it important to evacuate an A/C system before charging?
• To remove old refrigerant
• To reduce oil contamination
• To remove air and moisture 3 / 4

• To test the expansion valve

Rationale: Air and moisture reduce cooling efficiency and can damage

components, so evacuation is necessary before charging.

• What could cause the evaporator to freeze?
• Low refrigerant flow
• High ambient temperature
• Restricted airflow across the evaporator
• Faulty condenser fan

Rationale: Restricted airflow reduces heat transfer, causing the evaporator

temperature to drop below freezing and ice to form.

• What is the primary function of the condenser fan?
• Increase cabin airflow
• Lubricate compressor
• Assist in heat dissipation from the condenser
• Regulate refrigerant flow

Rationale: The condenser fan ensures sufficient airflow across the

condenser to release heat from the high-pressure refrigerant.

• What does the term “superheat” refer to?
• Refrigerant pressure above design limits
• Compressor temperature
• Temperature of refrigerant vapor above its boiling point in the

evaporator

• Heat in the condenser
• / 4