HVAC Excellence Certification
Exam Questions And Correct
Answers (Verified Answers)
Plus Rationales 2025 Q&A |
Instant Download PDF
1. A split system air conditioner is short cycling. MOST likely cause:
A. Oversized thermostat wire
B. Undersized ductwork or improper load sizing
C. Excess refrigerant always
D. High airflow only
Answer: B
Rationale: Short cycling commonly occurs when the system is oversized for the
load or airflow is restricted.
2. A refrigeration system has low suction pressure and high superheat. MOST
likely issue:
A. Overcharge of refrigerant
B. Restricted metering device or low refrigerant charge
C. Dirty condenser only
D. High voltage supply
Answer: B
Rationale: Low suction pressure with high superheat indicates starvation at the
evaporator.
,3. A compressor overheats and trips internal protection. MOST likely cause:
A. Proper lubrication
B. Insufficient refrigerant return or high discharge pressure
C. Oversized evaporator
D. Low voltage only
Answer: B
Rationale: Compressor overheating is commonly caused by poor cooling or high
head pressure.
4. A technician measures zero airflow across the evaporator coil. FIRST check:
A. Refrigerant color
B. Blower operation and filter condition
C. Condenser size
D. Thermostat battery only
Answer: B
Rationale: No airflow is usually caused by blower failure or severe restriction.
5. Frost is forming on the suction line near the evaporator. MOST likely cause:
A. Overcharge
B. Restricted airflow or low refrigerant charge
C. Dirty condenser fan only
D. High ambient temperature
Answer: B
Rationale: Low pressure and poor heat transfer cause freezing conditions.
6. A system has high head pressure. MOST likely cause:
A. Clean condenser coil
B. Dirty condenser coil or non-condensables in system
C. Low ambient temperature
D. Oversized evaporator
,Answer: B
Rationale: Heat rejection problems raise head pressure.
7. A TXV (thermostatic expansion valve) is hunting. MOST likely cause:
A. Stable load
B. Improper superheat setting or unstable refrigerant flow
C. Oversized compressor
D. Clean coil
Answer: B
Rationale: Hunting occurs when valve cannot stabilize flow.
8. A capacitor start motor hums but does not start. MOST likely issue:
A. Good capacitor
B. Failed start capacitor
C. Oversized breaker
D. High airflow
Answer: B
Rationale: Start capacitor failure prevents motor starting torque.
9. A split system has low cooling but normal airflow. MOST likely cause:
A. Dirty filter
B. Low refrigerant charge
C. High airflow
D. Oversized duct
Answer: B
Rationale: Normal airflow with poor cooling indicates refrigerant issue.
10. A condenser fan is running but head pressure remains high. MOST likely
cause:
A. Dirty condenser coil
B. Oversized fan motor
, C. Low suction pressure
D. High thermostat setting
Answer: A
Rationale: Dirty coils restrict heat rejection.
11. A system has high subcooling and low superheat. MOST likely cause:
A. Undercharge
B. Overcharge or liquid back-up
C. Dirty filter
D. Low airflow only
Answer: B
Rationale: High subcooling indicates excess refrigerant in condenser.
12. Ice is forming on the evaporator coil. MOST likely cause:
A. Proper airflow
B. Restricted airflow or low refrigerant charge
C. High voltage
D. Oversized compressor
Answer: B
Rationale: Ice forms when coil temperature drops too low.
13. A compressor draws high amperage at startup repeatedly. MOST likely
cause:
A. Normal condition
B. Hard starting due to pressure imbalance or capacitor failure
C. Clean system
D. Low load
Answer: B
Rationale: High inrush current indicates starting stress.
Exam Questions And Correct
Answers (Verified Answers)
Plus Rationales 2025 Q&A |
Instant Download PDF
1. A split system air conditioner is short cycling. MOST likely cause:
A. Oversized thermostat wire
B. Undersized ductwork or improper load sizing
C. Excess refrigerant always
D. High airflow only
Answer: B
Rationale: Short cycling commonly occurs when the system is oversized for the
load or airflow is restricted.
2. A refrigeration system has low suction pressure and high superheat. MOST
likely issue:
A. Overcharge of refrigerant
B. Restricted metering device or low refrigerant charge
C. Dirty condenser only
D. High voltage supply
Answer: B
Rationale: Low suction pressure with high superheat indicates starvation at the
evaporator.
,3. A compressor overheats and trips internal protection. MOST likely cause:
A. Proper lubrication
B. Insufficient refrigerant return or high discharge pressure
C. Oversized evaporator
D. Low voltage only
Answer: B
Rationale: Compressor overheating is commonly caused by poor cooling or high
head pressure.
4. A technician measures zero airflow across the evaporator coil. FIRST check:
A. Refrigerant color
B. Blower operation and filter condition
C. Condenser size
D. Thermostat battery only
Answer: B
Rationale: No airflow is usually caused by blower failure or severe restriction.
5. Frost is forming on the suction line near the evaporator. MOST likely cause:
A. Overcharge
B. Restricted airflow or low refrigerant charge
C. Dirty condenser fan only
D. High ambient temperature
Answer: B
Rationale: Low pressure and poor heat transfer cause freezing conditions.
6. A system has high head pressure. MOST likely cause:
A. Clean condenser coil
B. Dirty condenser coil or non-condensables in system
C. Low ambient temperature
D. Oversized evaporator
,Answer: B
Rationale: Heat rejection problems raise head pressure.
7. A TXV (thermostatic expansion valve) is hunting. MOST likely cause:
A. Stable load
B. Improper superheat setting or unstable refrigerant flow
C. Oversized compressor
D. Clean coil
Answer: B
Rationale: Hunting occurs when valve cannot stabilize flow.
8. A capacitor start motor hums but does not start. MOST likely issue:
A. Good capacitor
B. Failed start capacitor
C. Oversized breaker
D. High airflow
Answer: B
Rationale: Start capacitor failure prevents motor starting torque.
9. A split system has low cooling but normal airflow. MOST likely cause:
A. Dirty filter
B. Low refrigerant charge
C. High airflow
D. Oversized duct
Answer: B
Rationale: Normal airflow with poor cooling indicates refrigerant issue.
10. A condenser fan is running but head pressure remains high. MOST likely
cause:
A. Dirty condenser coil
B. Oversized fan motor
, C. Low suction pressure
D. High thermostat setting
Answer: A
Rationale: Dirty coils restrict heat rejection.
11. A system has high subcooling and low superheat. MOST likely cause:
A. Undercharge
B. Overcharge or liquid back-up
C. Dirty filter
D. Low airflow only
Answer: B
Rationale: High subcooling indicates excess refrigerant in condenser.
12. Ice is forming on the evaporator coil. MOST likely cause:
A. Proper airflow
B. Restricted airflow or low refrigerant charge
C. High voltage
D. Oversized compressor
Answer: B
Rationale: Ice forms when coil temperature drops too low.
13. A compressor draws high amperage at startup repeatedly. MOST likely
cause:
A. Normal condition
B. Hard starting due to pressure imbalance or capacitor failure
C. Clean system
D. Low load
Answer: B
Rationale: High inrush current indicates starting stress.
