Certification Practice Exam Questions And

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

• What is the primary purpose of superheat in a refrigeration system?
• To increase compressor efficiency
• To ensure only vapor enters the compressor
• To raise condenser pressure
• To lower evaporator pressure

Rationale: Superheat ensures that all refrigerant is vapor before reaching

the compressor, preventing damage from liquid slugging.

• What is the most accurate method for checking the refrigerant charge in

a system with a thermostatic expansion valve (TXV)?

• Measuring suction pressure
• Measuring compressor amperage 1 / 4

• Measuring subcooling
• Measuring superheat

Rationale: TXV systems maintain constant superheat, so subcooling is the

correct method to verify charge accuracy.

• What component controls the flow of refrigerant into the evaporator

coil?

• Compressor
• Accumulator
• Expansion device
• Receiver

Rationale: The expansion device meters refrigerant to the evaporator to

maintain proper pressure and temperature.

• Which of the following refrigerants is classified as a hydrofluorocarbon

(HFC)?

A) R-22

• R-134a

C) R-12

D) R-717

Rationale: R-134a is an HFC with no chlorine, unlike HCFCs and CFCs which

harm the ozone layer. 2 / 4

• In a split system, the metering device is located in which component?
• Condenser
• Compressor
• Indoor unit
• Outdoor unit

Rationale: In most split systems, the expansion device is installed near or

within the indoor coil.

• What is the main function of the compressor in the refrigeration cycle?
• Absorb heat
• Raise refrigerant pressure and temperature
• Condense vapor
• Control superheat

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

pressure, high-temperature gas for condensation.

• What safety device prevents the compressor from operating under low

suction pressure?

• Low-pressure control
• High-pressure control
• Thermostat 3 / 4

• Crankcase heater

Rationale: The low-pressure control shuts down the compressor to prevent

damage from low refrigerant flow or freezing.

• What is the term for heat energy absorbed or released during a change

of state without changing temperature?

• Sensible heat
• Latent heat
• Conduction
• Convection

Rationale: Latent heat is the energy involved in phase changes, such as

evaporation or condensation.

• When performing a vacuum on a system, what micron level should be

reached before charging?

• 1500 microns
• 1000 microns
• 500 microns or lower
• 200 microns

Rationale: A vacuum level of 500 microns ensures removal of moisture and

non-condensables before charging.

• / 4