FDNY Z-52 Refrigeration Engineering
Examination Questions And Correct
Answers (Verified Answers) Plus
Rationales 2026 Q&A | Instant
Download Pdf
1.
A refrigeration system in a high-rise facility shows a sudden drop in cooling
performance while pressures remain stable. What is the MOST likely cause?
A. Overcharged system
B. Faulty expansion valve
C. Dirty condenser
D. High ambient temperature
Answer: B
Rationale: Stable pressures with reduced cooling indicate improper refrigerant
metering at the expansion device.
2.
During inspection, a technician finds frost forming only on part of the evaporator
coil. What is the MOST likely cause?
A. Complete system failure
B. Partial refrigerant starvation
C. Overcharged system
D. High head pressure
,Answer: B
Rationale: Uneven frost patterns typically indicate insufficient refrigerant
distribution.
3.
A compressor repeatedly trips on overload protection during normal operation.
What is the MOST likely cause?
A. Clean condenser
B. High discharge pressure
C. Low refrigerant charge
D. Low ambient temperature
Answer: B
Rationale: Excessive head pressure increases compressor workload and electrical
load.
4.
A technician observes continuous bubbling in the sight glass. What does this
indicate?
A. Proper refrigerant charge
B. Low refrigerant charge or flashing liquid line
C. Overcharged system
D. Clean system condition
Answer: B
Rationale: Bubbles indicate insufficient liquid refrigerant at the expansion device.
5.
What is the PRIMARY function of a refrigeration compressor?
A. Absorb heat from space
B. Increase refrigerant pressure and temperature
,C. Control airflow
D. Store refrigerant
Answer: B
Rationale: The compressor raises refrigerant pressure for heat rejection in the
condenser.
6.
A condenser fan motor fails in a system operating under full load. What is the
immediate effect?
A. Reduced suction pressure
B. Increased head pressure
C. Increased evaporator efficiency
D. Lower discharge temperature
Answer: B
Rationale: Loss of heat rejection increases condensing pressure.
7.
A system shows high superheat at the evaporator outlet. What is the MOST likely
cause?
A. Overfeeding refrigerant
B. Underfeeding refrigerant
C. Dirty condenser
D. Excess oil in system
Answer: B
Rationale: High superheat indicates insufficient refrigerant flow into the
evaporator.
8.
, A refrigeration system has low suction pressure and low cooling output. MOST
likely cause?
A. Overcharged system
B. Restricted refrigerant flow
C. Dirty condenser
D. High ambient temperature
Answer: B
Rationale: Flow restriction reduces evaporator performance and suction pressure.
9.
What is the purpose of subcooling in a refrigeration system?
A. Increase compressor speed
B. Ensure liquid refrigerant stability before expansion
C. Reduce condenser size
D. Increase evaporator pressure
Answer: B
Rationale: Subcooling prevents flash gas formation in the liquid line.
10.
A compressor is noisy during startup and produces knocking sounds. MOST likely
cause?
A. Clean system
B. Liquid refrigerant entering compressor
C. Low load condition
D. High ambient temperature
Answer: B
Rationale: Liquid slugging causes mechanical damage and knocking.
11.
Examination Questions And Correct
Answers (Verified Answers) Plus
Rationales 2026 Q&A | Instant
Download Pdf
1.
A refrigeration system in a high-rise facility shows a sudden drop in cooling
performance while pressures remain stable. What is the MOST likely cause?
A. Overcharged system
B. Faulty expansion valve
C. Dirty condenser
D. High ambient temperature
Answer: B
Rationale: Stable pressures with reduced cooling indicate improper refrigerant
metering at the expansion device.
2.
During inspection, a technician finds frost forming only on part of the evaporator
coil. What is the MOST likely cause?
A. Complete system failure
B. Partial refrigerant starvation
C. Overcharged system
D. High head pressure
,Answer: B
Rationale: Uneven frost patterns typically indicate insufficient refrigerant
distribution.
3.
A compressor repeatedly trips on overload protection during normal operation.
What is the MOST likely cause?
A. Clean condenser
B. High discharge pressure
C. Low refrigerant charge
D. Low ambient temperature
Answer: B
Rationale: Excessive head pressure increases compressor workload and electrical
load.
4.
A technician observes continuous bubbling in the sight glass. What does this
indicate?
A. Proper refrigerant charge
B. Low refrigerant charge or flashing liquid line
C. Overcharged system
D. Clean system condition
Answer: B
Rationale: Bubbles indicate insufficient liquid refrigerant at the expansion device.
5.
What is the PRIMARY function of a refrigeration compressor?
A. Absorb heat from space
B. Increase refrigerant pressure and temperature
,C. Control airflow
D. Store refrigerant
Answer: B
Rationale: The compressor raises refrigerant pressure for heat rejection in the
condenser.
6.
A condenser fan motor fails in a system operating under full load. What is the
immediate effect?
A. Reduced suction pressure
B. Increased head pressure
C. Increased evaporator efficiency
D. Lower discharge temperature
Answer: B
Rationale: Loss of heat rejection increases condensing pressure.
7.
A system shows high superheat at the evaporator outlet. What is the MOST likely
cause?
A. Overfeeding refrigerant
B. Underfeeding refrigerant
C. Dirty condenser
D. Excess oil in system
Answer: B
Rationale: High superheat indicates insufficient refrigerant flow into the
evaporator.
8.
, A refrigeration system has low suction pressure and low cooling output. MOST
likely cause?
A. Overcharged system
B. Restricted refrigerant flow
C. Dirty condenser
D. High ambient temperature
Answer: B
Rationale: Flow restriction reduces evaporator performance and suction pressure.
9.
What is the purpose of subcooling in a refrigeration system?
A. Increase compressor speed
B. Ensure liquid refrigerant stability before expansion
C. Reduce condenser size
D. Increase evaporator pressure
Answer: B
Rationale: Subcooling prevents flash gas formation in the liquid line.
10.
A compressor is noisy during startup and produces knocking sounds. MOST likely
cause?
A. Clean system
B. Liquid refrigerant entering compressor
C. Low load condition
D. High ambient temperature
Answer: B
Rationale: Liquid slugging causes mechanical damage and knocking.
11.
