BOC Level I Skills Assessment / Field
Project Evaluation Exam Practice
Questions And Correct Answers
(Verified Answers) Plus Rationales 2026
Q&A | Instant Download Pdf
1. In HVAC preventive maintenance, what is the primary purpose of
regularly replacing air filters?
A. Increase refrigerant pressure
B. Reduce compressor noise
C. Improve airflow efficiency and indoor air quality
D. Increase thermostat sensitivity
C
Regular replacement of air filters ensures unobstructed airflow,
improves system efficiency, and maintains acceptable indoor air
quality by trapping dust and particulates.
2. Which tool is most appropriate for checking electrical current in a live
circuit?
, A. Ohmmeter
B. Voltmeter
C. Clamp meter
D. Tachometer
C
A clamp meter allows safe measurement of current without
disconnecting the circuit, making it ideal for live electrical systems.
3. What is the main function of a building’s backflow preventer?
A. Increase water pressure
B. Prevent contamination of potable water supply
C. Reduce pipe corrosion
D. Filter sediment from water
B
Backflow preventers ensure that contaminated water does not
reverse flow into the clean water supply system.
4. Which safety practice is essential before performing electrical
maintenance?
A. Increasing voltage supply
B. Lockout/tagout procedure
C. Removing all grounding wires
D. Using metallic tools only
B
Lockout/tagout procedures ensure that equipment is properly de-
, energized and cannot be accidentally re-energized during
maintenance.
5. What is the purpose of a thermostat in HVAC systems?
A. Measure refrigerant flow
B. Control indoor humidity only
C. Regulate temperature by controlling system operation
D. Increase compressor speed
C
A thermostat monitors ambient temperature and signals HVAC
equipment to maintain the desired setpoint.
6. Which is a common sign of a failing bearing in a motor?
A. Reduced airflow
B. Excessive vibration and noise
C. Increased voltage stability
D. Lower refrigerant levels
B
Failing bearings typically produce abnormal vibration and noise due
to mechanical wear and friction.
7. What is the primary function of a circuit breaker?
A. Store electrical energy
B. Increase voltage supply
C. Protect circuits from overloads and short circuits
D. Convert AC to DC
, C
Circuit breakers automatically interrupt electrical flow during
overload or fault conditions to prevent damage or fire.
8. In plumbing systems, what does a P-trap primarily prevent?
A. Water hammer
B. Sewer gas entry
C. Pipe freezing
D. Pressure loss
B
A P-trap holds water that acts as a seal to prevent sewer gases from
entering occupied spaces.
9. Which instrument is used to measure relative humidity?
A. Hygrometer
B. Barometer
C. Anemometer
D. Manometer
A
A hygrometer measures the amount of moisture in the air as relative
humidity.
10. What is the function of a variable air volume (VAV) system?
A. Constant airflow at all times
B. Vary airflow based on cooling/heating demand
C. Increase refrigerant compression
Project Evaluation Exam Practice
Questions And Correct Answers
(Verified Answers) Plus Rationales 2026
Q&A | Instant Download Pdf
1. In HVAC preventive maintenance, what is the primary purpose of
regularly replacing air filters?
A. Increase refrigerant pressure
B. Reduce compressor noise
C. Improve airflow efficiency and indoor air quality
D. Increase thermostat sensitivity
C
Regular replacement of air filters ensures unobstructed airflow,
improves system efficiency, and maintains acceptable indoor air
quality by trapping dust and particulates.
2. Which tool is most appropriate for checking electrical current in a live
circuit?
, A. Ohmmeter
B. Voltmeter
C. Clamp meter
D. Tachometer
C
A clamp meter allows safe measurement of current without
disconnecting the circuit, making it ideal for live electrical systems.
3. What is the main function of a building’s backflow preventer?
A. Increase water pressure
B. Prevent contamination of potable water supply
C. Reduce pipe corrosion
D. Filter sediment from water
B
Backflow preventers ensure that contaminated water does not
reverse flow into the clean water supply system.
4. Which safety practice is essential before performing electrical
maintenance?
A. Increasing voltage supply
B. Lockout/tagout procedure
C. Removing all grounding wires
D. Using metallic tools only
B
Lockout/tagout procedures ensure that equipment is properly de-
, energized and cannot be accidentally re-energized during
maintenance.
5. What is the purpose of a thermostat in HVAC systems?
A. Measure refrigerant flow
B. Control indoor humidity only
C. Regulate temperature by controlling system operation
D. Increase compressor speed
C
A thermostat monitors ambient temperature and signals HVAC
equipment to maintain the desired setpoint.
6. Which is a common sign of a failing bearing in a motor?
A. Reduced airflow
B. Excessive vibration and noise
C. Increased voltage stability
D. Lower refrigerant levels
B
Failing bearings typically produce abnormal vibration and noise due
to mechanical wear and friction.
7. What is the primary function of a circuit breaker?
A. Store electrical energy
B. Increase voltage supply
C. Protect circuits from overloads and short circuits
D. Convert AC to DC
, C
Circuit breakers automatically interrupt electrical flow during
overload or fault conditions to prevent damage or fire.
8. In plumbing systems, what does a P-trap primarily prevent?
A. Water hammer
B. Sewer gas entry
C. Pipe freezing
D. Pressure loss
B
A P-trap holds water that acts as a seal to prevent sewer gases from
entering occupied spaces.
9. Which instrument is used to measure relative humidity?
A. Hygrometer
B. Barometer
C. Anemometer
D. Manometer
A
A hygrometer measures the amount of moisture in the air as relative
humidity.
10. What is the function of a variable air volume (VAV) system?
A. Constant airflow at all times
B. Vary airflow based on cooling/heating demand
C. Increase refrigerant compression
