HVAC Certification Practice Exam

HVAC Excellence Professional Technician HVAC Certification Practice Exam Questions And Correct Answers (Verified Answers) Plus Rationales 2026 Q&A | Instant Download Pdf

• What is the primary function of a compressor in an HVAC system?

a) To absorb heat from the evaporator

b) To raise the pressure and temperature of the refrigerant vapor

c) To condense refrigerant into liquid

d) To meter refrigerant flow

Rationale: The compressor compresses low-pressure vapor into high-

pressure vapor, enabling heat rejection in the condenser.

• What is the purpose of the metering device in a refrigeration cycle?

a) To heat the refrigerant

b) To increase refrigerant pressure 1 / 4

c) To reduce refrigerant pressure and control flow to the evaporator

d) To remove moisture from the refrigerant

Rationale: The metering device creates a pressure drop allowing liquid

refrigerant to expand and absorb heat in the evaporator.

• Which component in an air conditioning system rejects heat to the

outdoor air?

a) Evaporator coil

b) Condenser coil

c) Expansion valve

d) Filter drier

Rationale: The condenser coil releases absorbed heat from the refrigerant

to the outdoor environment.

• What is the normal subcooling range for a properly charged air

conditioning system?

• 1–3°F
• 4–6°F
• 8–12°F
• 15–20°F

Rationale: Typical subcooling for properly charged systems ranges

between 8–12°F, ensuring liquid refrigerant enters the metering device. 2 / 4

• What instrument measures both pressure and temperature on an HVAC

system?

a) Multimeter

b) Thermometer

c) Manifold gauge set

d) Psychrometer

Rationale: Manifold gauge sets are used to read high and low pressures

and correlate them to refrigerant temperatures.

• Which type of refrigerant is classified as an HFC?

a) R-12

b) R-22

c) R-134a

d) R-717

Rationale: R-134a is a hydrofluorocarbon (HFC) that contains no chlorine,

making it less harmful to the ozone layer.

• What happens when air or moisture enters a refrigeration system?

a) Increases cooling efficiency

b) Causes system corrosion and pressure fluctuations

c) Reduces compressor oil circulation 3 / 4

d) Increases system capacity

Rationale: Air and moisture cause acid formation, corrosion, and erratic

system operation.

• What type of compressor is commonly used in residential split systems?

a) Centrifugal

b) Rotary

c) Scroll

d) Screw

Rationale: Scroll compressors are efficient and reliable, making them

standard in residential HVAC applications.

9. The evaporator coil is located:

a) On the low-pressure side of the system

b) On the high-pressure side

c) Between condenser and compressor

d) In the liquid line

Rationale: The evaporator operates at low pressure where refrigerant

absorbs heat and evaporates.

• What safety control prevents the compressor from running with low

refrigerant pressure?

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