AZ L-75 Refrigeration & Heating Exam
Questions And Correct Answers
(Verified Answers) Plus Rationale2026
Q&A| Instant Download Pdf
1. What is the primary purpose of a refrigeration compressor?
A. To absorb heat from the evaporator
B. To reject heat to the condenser
C. To raise refrigerant pressure and circulate refrigerant
D. To meter refrigerant to the evaporator
Rationale: The compressor increases refrigerant pressure and moves
refrigerant through the system, enabling the refrigeration cycle.
2. Superheat is measured at which point in a refrigeration system?
A. Compressor inlet
B. Condenser outlet
C. Evaporator outlet
D. Metering device inlet
Rationale: Superheat is measured at the evaporator outlet to ensure vapor
only enters the compressor.
3. What device controls refrigerant flow into the evaporator?
A. Accumulator
B. Metering device
C. Liquid receiver
D. Solenoid valve
Rationale: The metering device creates a pressure drop and controls the
amount of refrigerant entering the evaporator.
,4. Which refrigerant is commonly used in medium-temperature
commercial refrigeration?
A. R-410A
B. R-22
C. R-404A
D. R-718
Rationale: R-404A is widely used for commercial coolers and freezers.
5. Low superheat at the evaporator typically indicates:
A. Undercharged system
B. Overfeeding or flooding evaporator
C. Dirty condenser
D. A restriction in the liquid line
Rationale: Low superheat means too much liquid refrigerant is entering
the evaporator.
6. High head pressure is often caused by:
A. Low ambient temperature
B. Low refrigerant charge
C. Restricted metering device
D. Dirty condenser coil
Rationale: Dirty condensers reduce heat rejection, raising head pressure.
7. The primary function of a heat exchanger is to:
A. Cool the condenser
B. Increase airflow
C. Transfer heat between two fluids
D. Remove moisture
Rationale: Heat exchangers move heat from one medium to another.
8. What component protects a compressor from overheating?
A. Contactor
B. Suction filter
C. Internal thermal overload
, D. Start capacitor
Rationale: Compressors have internal overloads that trip when
temperatures become excessive.
9. A discharge line temperature of 260°F typically indicates:
A. Normal operation
B. High superheat and overheating
C. Low subcooling
D. Low evaporator load
Rationale: High discharge temperatures signal overheating and
insufficient cooling of the compressor.
10. Subcooling is measured at:
A. Evaporator outlet
B. Compressor inlet
C. Condenser outlet
D. Suction line
Rationale: Subcooling indicates how much liquid is cooled below
saturation at the condenser outlet.
11. The purpose of a crankcase heater is to:
A. Cool the compressor oil
B. Prevent refrigerant migration into the oil during off cycles
C. Reduce compressor sound
D. Control metering device operation
Rationale: Crankcase heaters prevent refrigerant from condensing in the
compressor oil.
12. Which refrigerant is classified as mildly flammable (A2L)?
A. R-22
B. R-32
C. R-134a
Questions And Correct Answers
(Verified Answers) Plus Rationale2026
Q&A| Instant Download Pdf
1. What is the primary purpose of a refrigeration compressor?
A. To absorb heat from the evaporator
B. To reject heat to the condenser
C. To raise refrigerant pressure and circulate refrigerant
D. To meter refrigerant to the evaporator
Rationale: The compressor increases refrigerant pressure and moves
refrigerant through the system, enabling the refrigeration cycle.
2. Superheat is measured at which point in a refrigeration system?
A. Compressor inlet
B. Condenser outlet
C. Evaporator outlet
D. Metering device inlet
Rationale: Superheat is measured at the evaporator outlet to ensure vapor
only enters the compressor.
3. What device controls refrigerant flow into the evaporator?
A. Accumulator
B. Metering device
C. Liquid receiver
D. Solenoid valve
Rationale: The metering device creates a pressure drop and controls the
amount of refrigerant entering the evaporator.
,4. Which refrigerant is commonly used in medium-temperature
commercial refrigeration?
A. R-410A
B. R-22
C. R-404A
D. R-718
Rationale: R-404A is widely used for commercial coolers and freezers.
5. Low superheat at the evaporator typically indicates:
A. Undercharged system
B. Overfeeding or flooding evaporator
C. Dirty condenser
D. A restriction in the liquid line
Rationale: Low superheat means too much liquid refrigerant is entering
the evaporator.
6. High head pressure is often caused by:
A. Low ambient temperature
B. Low refrigerant charge
C. Restricted metering device
D. Dirty condenser coil
Rationale: Dirty condensers reduce heat rejection, raising head pressure.
7. The primary function of a heat exchanger is to:
A. Cool the condenser
B. Increase airflow
C. Transfer heat between two fluids
D. Remove moisture
Rationale: Heat exchangers move heat from one medium to another.
8. What component protects a compressor from overheating?
A. Contactor
B. Suction filter
C. Internal thermal overload
, D. Start capacitor
Rationale: Compressors have internal overloads that trip when
temperatures become excessive.
9. A discharge line temperature of 260°F typically indicates:
A. Normal operation
B. High superheat and overheating
C. Low subcooling
D. Low evaporator load
Rationale: High discharge temperatures signal overheating and
insufficient cooling of the compressor.
10. Subcooling is measured at:
A. Evaporator outlet
B. Compressor inlet
C. Condenser outlet
D. Suction line
Rationale: Subcooling indicates how much liquid is cooled below
saturation at the condenser outlet.
11. The purpose of a crankcase heater is to:
A. Cool the compressor oil
B. Prevent refrigerant migration into the oil during off cycles
C. Reduce compressor sound
D. Control metering device operation
Rationale: Crankcase heaters prevent refrigerant from condensing in the
compressor oil.
12. Which refrigerant is classified as mildly flammable (A2L)?
A. R-22
B. R-32
C. R-134a
