RETA CIRO HIGH-PRESSURE SYSTEM
TROUBLESHOOTING PRACTICE EXAM WITH
ACTUAL QUESTIONS AND VERIFIED
ANSWERS, PLUS EXPLAINED
RATIONALES/EXPERT VERIFIED FOR
GUARANTEED 100% PASS 2026/LATEST
UPDATE/INSTANT DOWNLOAD PDF
1. A high-pressure ammonia refrigeration system is operating with a
head pressure significantly above the expected condensing
pressure for the current ambient conditions. The condenser fans are
running, but the discharge pressure continues to rise. Which
condition should an operator investigate first when determining
whether the condenser is rejecting heat effectively?
A. Excessively low suction pressure
B. Insufficient condenser airflow or inadequate heat-transfer surface
C. Excessive evaporator superheat
D. Low oil level in the compressor
Answer: B. Insufficient condenser airflow or inadequate heat-
transfer surface
Rationale: A high head pressure commonly results when the
condenser cannot reject the required heat to the surrounding medium.
Fouled condenser surfaces, inadequate airflow, failed fans, incorrect
fan rotation, blocked air passages, or excessive ambient temperature
can all reduce heat rejection. Suction pressure and compressor oil
level may affect system operation but are not the first indicators of
condenser heat-transfer failure.
1
, 2. An ammonia condenser is equipped with several axial fans. During
a high-pressure condition, an operator notices that one fan is
rotating in the opposite direction from the others after recent
electrical maintenance. What is the most likely consequence?
A. Increased condenser capacity
B. Reduced refrigerant circulation through the evaporators
C. Reduced condenser airflow and elevated condensing pressure
D. Lower compressor discharge temperature
Answer: C. Reduced condenser airflow and elevated condensing
pressure
Rationale: An improperly rotating fan can substantially reduce airflow
through an air-cooled condenser. The resulting reduction in heat
rejection raises condensing temperature and discharge pressure. Fan
rotation should be verified after motor or electrical work because
incorrect phase sequence can reverse three-phase motors.
3. A high-pressure receiver in an ammonia system is approaching its
maximum allowable operating level. The condenser outlet pressure
is elevated, while liquid level in the receiver continues to rise.
Which troubleshooting consideration is most important?
A. Whether liquid is being adequately transferred from the receiver to
the system
B. Whether the evaporator has excessive superheat
C. Whether the suction accumulator is empty
D. Whether compressor capacity is too low
Answer: A. Whether liquid is being adequately transferred from the
receiver to the system
Rationale: A rising receiver level can indicate that liquid is
accumulating faster than it is being distributed to downstream loads.
2
,Restrictions in liquid piping, improperly positioned valves, control
problems, excessive system charge, or inadequate liquid demand can
contribute. A high receiver level can also reduce available
condenser/receiver volume and contribute to abnormal system
pressures.
4. A compressor discharge pressure is 235 psig while the
corresponding condensing temperature appears substantially higher
than expected for the available cooling medium. The operator
confirms that the condenser fans are operating. What additional
measurement would be most useful in diagnosing the problem?
A. Compressor crankcase temperature only
B. Condenser inlet and outlet temperature and pressure conditions
C. Evaporator suction temperature only
D. Oil separator sight-glass level only
Answer: B. Condenser inlet and outlet temperature and pressure
conditions
Rationale: Comparing refrigerant conditions entering and leaving the
condenser with the available cooling-medium conditions helps
determine whether the condenser is transferring heat properly. A
relatively small temperature change across the cooling medium,
abnormal refrigerant-side conditions, or excessive condensing
temperature can help distinguish airflow, fouling, flooding, or
refrigerant-side problems.
5. An operator discovers that a high-pressure system has accumulated
a significant amount of non-condensable gas. Which symptom
would most strongly support this diagnosis?
3
, A. Head pressure higher than expected for the actual condenser
temperature
B. Extremely low oil temperature
C. Abnormally low receiver level with no liquid production
D. Low evaporator pressure caused by excessive suction superheat
Answer: A. Head pressure higher than expected for the actual
condenser temperature
Rationale: Non-condensable gases occupy condenser volume and
contribute their own partial pressure to the measured system pressure.
Consequently, total discharge pressure can be substantially higher
than the pressure corresponding to the actual refrigerant saturation
temperature. Persistent high head pressure despite apparently
adequate condenser operation is a classic indication requiring
investigation for non-condensables.
6. Which situation most commonly introduces non-condensable gases
into an ammonia refrigeration system?
A. Excessive evaporator airflow
B. Improper evacuation or opening the system to atmospheric
contamination
C. Excessive liquid subcooling
D. High compressor volumetric efficiency
Answer: B. Improper evacuation or opening the system to
atmospheric contamination
Rationale: Air and other non-condensables can enter during
maintenance, leaks under vacuum conditions, improper evacuation, or
procedures that expose components to atmosphere. Proper evacuation,
purging, and maintenance practices minimize this risk. Non-
4
TROUBLESHOOTING PRACTICE EXAM WITH
ACTUAL QUESTIONS AND VERIFIED
ANSWERS, PLUS EXPLAINED
RATIONALES/EXPERT VERIFIED FOR
GUARANTEED 100% PASS 2026/LATEST
UPDATE/INSTANT DOWNLOAD PDF
1. A high-pressure ammonia refrigeration system is operating with a
head pressure significantly above the expected condensing
pressure for the current ambient conditions. The condenser fans are
running, but the discharge pressure continues to rise. Which
condition should an operator investigate first when determining
whether the condenser is rejecting heat effectively?
A. Excessively low suction pressure
B. Insufficient condenser airflow or inadequate heat-transfer surface
C. Excessive evaporator superheat
D. Low oil level in the compressor
Answer: B. Insufficient condenser airflow or inadequate heat-
transfer surface
Rationale: A high head pressure commonly results when the
condenser cannot reject the required heat to the surrounding medium.
Fouled condenser surfaces, inadequate airflow, failed fans, incorrect
fan rotation, blocked air passages, or excessive ambient temperature
can all reduce heat rejection. Suction pressure and compressor oil
level may affect system operation but are not the first indicators of
condenser heat-transfer failure.
1
, 2. An ammonia condenser is equipped with several axial fans. During
a high-pressure condition, an operator notices that one fan is
rotating in the opposite direction from the others after recent
electrical maintenance. What is the most likely consequence?
A. Increased condenser capacity
B. Reduced refrigerant circulation through the evaporators
C. Reduced condenser airflow and elevated condensing pressure
D. Lower compressor discharge temperature
Answer: C. Reduced condenser airflow and elevated condensing
pressure
Rationale: An improperly rotating fan can substantially reduce airflow
through an air-cooled condenser. The resulting reduction in heat
rejection raises condensing temperature and discharge pressure. Fan
rotation should be verified after motor or electrical work because
incorrect phase sequence can reverse three-phase motors.
3. A high-pressure receiver in an ammonia system is approaching its
maximum allowable operating level. The condenser outlet pressure
is elevated, while liquid level in the receiver continues to rise.
Which troubleshooting consideration is most important?
A. Whether liquid is being adequately transferred from the receiver to
the system
B. Whether the evaporator has excessive superheat
C. Whether the suction accumulator is empty
D. Whether compressor capacity is too low
Answer: A. Whether liquid is being adequately transferred from the
receiver to the system
Rationale: A rising receiver level can indicate that liquid is
accumulating faster than it is being distributed to downstream loads.
2
,Restrictions in liquid piping, improperly positioned valves, control
problems, excessive system charge, or inadequate liquid demand can
contribute. A high receiver level can also reduce available
condenser/receiver volume and contribute to abnormal system
pressures.
4. A compressor discharge pressure is 235 psig while the
corresponding condensing temperature appears substantially higher
than expected for the available cooling medium. The operator
confirms that the condenser fans are operating. What additional
measurement would be most useful in diagnosing the problem?
A. Compressor crankcase temperature only
B. Condenser inlet and outlet temperature and pressure conditions
C. Evaporator suction temperature only
D. Oil separator sight-glass level only
Answer: B. Condenser inlet and outlet temperature and pressure
conditions
Rationale: Comparing refrigerant conditions entering and leaving the
condenser with the available cooling-medium conditions helps
determine whether the condenser is transferring heat properly. A
relatively small temperature change across the cooling medium,
abnormal refrigerant-side conditions, or excessive condensing
temperature can help distinguish airflow, fouling, flooding, or
refrigerant-side problems.
5. An operator discovers that a high-pressure system has accumulated
a significant amount of non-condensable gas. Which symptom
would most strongly support this diagnosis?
3
, A. Head pressure higher than expected for the actual condenser
temperature
B. Extremely low oil temperature
C. Abnormally low receiver level with no liquid production
D. Low evaporator pressure caused by excessive suction superheat
Answer: A. Head pressure higher than expected for the actual
condenser temperature
Rationale: Non-condensable gases occupy condenser volume and
contribute their own partial pressure to the measured system pressure.
Consequently, total discharge pressure can be substantially higher
than the pressure corresponding to the actual refrigerant saturation
temperature. Persistent high head pressure despite apparently
adequate condenser operation is a classic indication requiring
investigation for non-condensables.
6. Which situation most commonly introduces non-condensable gases
into an ammonia refrigeration system?
A. Excessive evaporator airflow
B. Improper evacuation or opening the system to atmospheric
contamination
C. Excessive liquid subcooling
D. High compressor volumetric efficiency
Answer: B. Improper evacuation or opening the system to
atmospheric contamination
Rationale: Air and other non-condensables can enter during
maintenance, leaks under vacuum conditions, improper evacuation, or
procedures that expose components to atmosphere. Proper evacuation,
purging, and maintenance practices minimize this risk. Non-
4
