Delaware HVACR Contractor
Examination Practice Exam 2026 | 100+
Questions & Answers with Detailed
Rationales | Complete Delaware HVACR
Contractor Licensing Exam Prep, Study
Guide, Test Review & Qualification
Preparation
1. What is the primary purpose of a refrigeration compressor?
A. To remove moisture from the evaporator
B. To circulate refrigerant and raise its pressure and temperature
C. To reduce condenser pressure
D. To meter refrigerant into the evaporator
Answer: B. To circulate refrigerant and raise its pressure and temperature
Rationale: The compressor draws low-pressure refrigerant vapor from the
evaporator and compresses it into a high-pressure, high-temperature vapor for
delivery to the condenser.
, 2. In a basic vapor-compression refrigeration system, which component
removes heat from the conditioned space?
A. Compressor
B. Condenser
C. Evaporator
D. Receiver
Answer: C. Evaporator
Rationale: The evaporator absorbs heat from the air, product, or space being
cooled as refrigerant evaporates inside the coil.
3. What is the main function of the condenser?
A. Absorb heat from the conditioned space
B. Reject heat from the refrigerant
C. Meter liquid refrigerant
D. Increase evaporator airflow
Answer: B. Reject heat from the refrigerant
Rationale: The condenser removes heat from the refrigerant and changes high-
pressure vapor into high-pressure liquid.
4. What device is commonly used to meter refrigerant into an evaporator?
A. Contactor
B. Expansion valve
C. Compressor
D. Accumulator
Answer: B. Expansion valve
Rationale: An expansion device creates a pressure drop and controls the amount
of refrigerant entering the evaporator.
, 5. What happens to refrigerant pressure as it passes through a properly
operating expansion device?
A. It increases
B. It remains constant
C. It decreases
D. It becomes atmospheric
Answer: C. It decreases
Rationale: The expansion device reduces refrigerant pressure, causing part of
the liquid refrigerant to flash into vapor and lowering its temperature.
6. Superheat is best described as:
A. The temperature of saturated liquid above its boiling point
B. The temperature of vapor above its saturation temperature
C. Condenser temperature minus outdoor temperature
D. Compressor temperature minus suction pressure
Answer: B. The temperature of vapor above its saturation temperature
Rationale: Superheat indicates how much a vapor's actual temperature exceeds
its saturation temperature at a given pressure.
7. Subcooling refers to:
A. Cooling a vapor below its saturation temperature
B. Cooling a liquid below its saturation temperature
C. Heating liquid refrigerant
D. Heating suction vapor
Answer: B. Cooling a liquid below its saturation temperature
Rationale: Subcooling is the temperature difference between the saturation
temperature and the actual temperature of a liquid refrigerant.
8. A high evaporator superheat reading can indicate:
, A. Excessive refrigerant flooding
B. A starved evaporator
C. An oversized condenser
D. Excessive liquid refrigerant in the compressor
Answer: B. A starved evaporator
Rationale: Excessive superheat often indicates insufficient refrigerant flow into
the evaporator, which can result from low charge or a restricted metering
device.
9. What is the purpose of a filter-drier?
A. Increase compressor speed
B. Remove moisture and contaminants from the refrigerant system
C. Increase suction pressure
D. Reduce condenser airflow
Answer: B. Remove moisture and contaminants from the refrigerant system
Rationale: Filter-driers trap debris and absorb moisture that can damage
components or react with refrigerant and oil.
10.Why is moisture harmful inside a refrigeration system?
A. It increases airflow
B. It can cause corrosion, freezing, and acid formation
C. It increases electrical voltage
D. It improves compressor lubrication
Answer: B. It can cause corrosion, freezing, and acid formation
Rationale: Moisture can freeze at metering devices and contribute to corrosion
and chemical reactions that produce acids.
11.What instrument is used to measure refrigerant pressure?
Examination Practice Exam 2026 | 100+
Questions & Answers with Detailed
Rationales | Complete Delaware HVACR
Contractor Licensing Exam Prep, Study
Guide, Test Review & Qualification
Preparation
1. What is the primary purpose of a refrigeration compressor?
A. To remove moisture from the evaporator
B. To circulate refrigerant and raise its pressure and temperature
C. To reduce condenser pressure
D. To meter refrigerant into the evaporator
Answer: B. To circulate refrigerant and raise its pressure and temperature
Rationale: The compressor draws low-pressure refrigerant vapor from the
evaporator and compresses it into a high-pressure, high-temperature vapor for
delivery to the condenser.
, 2. In a basic vapor-compression refrigeration system, which component
removes heat from the conditioned space?
A. Compressor
B. Condenser
C. Evaporator
D. Receiver
Answer: C. Evaporator
Rationale: The evaporator absorbs heat from the air, product, or space being
cooled as refrigerant evaporates inside the coil.
3. What is the main function of the condenser?
A. Absorb heat from the conditioned space
B. Reject heat from the refrigerant
C. Meter liquid refrigerant
D. Increase evaporator airflow
Answer: B. Reject heat from the refrigerant
Rationale: The condenser removes heat from the refrigerant and changes high-
pressure vapor into high-pressure liquid.
4. What device is commonly used to meter refrigerant into an evaporator?
A. Contactor
B. Expansion valve
C. Compressor
D. Accumulator
Answer: B. Expansion valve
Rationale: An expansion device creates a pressure drop and controls the amount
of refrigerant entering the evaporator.
, 5. What happens to refrigerant pressure as it passes through a properly
operating expansion device?
A. It increases
B. It remains constant
C. It decreases
D. It becomes atmospheric
Answer: C. It decreases
Rationale: The expansion device reduces refrigerant pressure, causing part of
the liquid refrigerant to flash into vapor and lowering its temperature.
6. Superheat is best described as:
A. The temperature of saturated liquid above its boiling point
B. The temperature of vapor above its saturation temperature
C. Condenser temperature minus outdoor temperature
D. Compressor temperature minus suction pressure
Answer: B. The temperature of vapor above its saturation temperature
Rationale: Superheat indicates how much a vapor's actual temperature exceeds
its saturation temperature at a given pressure.
7. Subcooling refers to:
A. Cooling a vapor below its saturation temperature
B. Cooling a liquid below its saturation temperature
C. Heating liquid refrigerant
D. Heating suction vapor
Answer: B. Cooling a liquid below its saturation temperature
Rationale: Subcooling is the temperature difference between the saturation
temperature and the actual temperature of a liquid refrigerant.
8. A high evaporator superheat reading can indicate:
, A. Excessive refrigerant flooding
B. A starved evaporator
C. An oversized condenser
D. Excessive liquid refrigerant in the compressor
Answer: B. A starved evaporator
Rationale: Excessive superheat often indicates insufficient refrigerant flow into
the evaporator, which can result from low charge or a restricted metering
device.
9. What is the purpose of a filter-drier?
A. Increase compressor speed
B. Remove moisture and contaminants from the refrigerant system
C. Increase suction pressure
D. Reduce condenser airflow
Answer: B. Remove moisture and contaminants from the refrigerant system
Rationale: Filter-driers trap debris and absorb moisture that can damage
components or react with refrigerant and oil.
10.Why is moisture harmful inside a refrigeration system?
A. It increases airflow
B. It can cause corrosion, freezing, and acid formation
C. It increases electrical voltage
D. It improves compressor lubrication
Answer: B. It can cause corrosion, freezing, and acid formation
Rationale: Moisture can freeze at metering devices and contribute to corrosion
and chemical reactions that produce acids.
11.What instrument is used to measure refrigerant pressure?
