CT Oil Heating Contractor Exam
Questions And Correct Answers
(Verified Answers) Plus Rationales 2026
Q&A| Instant Download Pdf
1. What is the primary purpose of a fuel oil filter in an oil heating system?
A. To reduce water content in the oil
B. To remove impurities and prevent nozzle clogging
C. To heat the oil before combustion
D. To control oil pressure
Answer: B
Rationale: Fuel oil filters remove impurities such as dirt, rust, and
debris, which can clog the nozzle and affect combustion efficiency.
2. Which type of oil burner is most commonly used in residential heating
systems?
A. Two-stage vaporizing burner
B. Pressure-atomizing burner
C. Rotary cup burner
D. Air-assisted atomizing burner
Answer: B
Rationale: Pressure-atomizing burners are common in residential
systems because they provide reliable, fine atomization and efficient
combustion.
3. What is the recommended operating temperature range for heating oil
in a storage tank?
A. 32–50°F
B. 90–120°F
C. 50–80°F
D. 100–150°F
Answer: C
, Rationale: Heating oil should be stored at moderate temperatures to
prevent waxing and maintain proper flow without risk of vaporization.
4. What is the function of the nozzle in an oil burner?
A. To control oil pressure
B. To filter impurities
C. To atomize the fuel into fine droplets for combustion
D. To regulate airflow
Answer: C
Rationale: The nozzle sprays the fuel oil as a fine mist, which ensures
efficient and complete combustion.
5. Which device in an oil heating system ignites the fuel-air mixture?
A. Oil filter
B. Ignition transformer and electrodes
C. Fan motor
D. Pressure regulator
Answer: B
Rationale: The ignition transformer produces a high-voltage spark at
the electrodes to ignite the atomized oil.
6. What is the purpose of a cad cell in an oil burner?
A. To measure oil temperature
B. To control airflow
C. To sense the flame and ensure safe operation
D. To regulate pressure
Answer: C
Rationale: The cadmium cell (cad cell) detects the presence of a flame
and signals the burner control to maintain safe operation.
7. What safety device shuts off the oil supply if the flame goes out?
A. Thermal fuse
B. Primary control with safety lockout
C. Pressure switch
D. Expansion tank
Answer: B
Rationale: Primary controls with safety lockout prevent oil from
flowing when there is no flame, avoiding fuel accumulation and fire
hazards.
8. Which factor has the greatest effect on combustion efficiency?
A. Oil storage temperature
, B. Air-to-fuel ratio
C. Nozzle size
D. Tank material
Answer: B
Rationale: Proper air-to-fuel ratio is critical for complete combustion;
too much or too little air reduces efficiency.
9. What is the standard color code for No. 2 heating oil?
A. Green
B. Red
C. Blue
D. Yellow
Answer: B
Rationale: No. 2 heating oil is typically dyed red to distinguish it from
diesel fuel and prevent misuse.
10. Which of the following is a common cause of smoky flames in
oil burners?
A. Dirty nozzle or improper air setting
B. High oil temperature
C. Too much combustion air
D. Excessive nozzle pressure
Answer: A
Rationale: A dirty nozzle or incorrect air adjustment leads to
incomplete combustion, producing smoke.
11. What is the purpose of the stack or chimney in an oil heating
system?
A. To heat the building
B. To vent combustion products safely outdoors
C. To regulate oil pressure
D. To filter air
Answer: B
Rationale: The chimney safely directs combustion gases, including
carbon monoxide, out of the building.
12. Which type of control maintains water temperature in an oil-fired
boiler?
A. Oil filter
B. Aquastat
C. Cad cell
Questions And Correct Answers
(Verified Answers) Plus Rationales 2026
Q&A| Instant Download Pdf
1. What is the primary purpose of a fuel oil filter in an oil heating system?
A. To reduce water content in the oil
B. To remove impurities and prevent nozzle clogging
C. To heat the oil before combustion
D. To control oil pressure
Answer: B
Rationale: Fuel oil filters remove impurities such as dirt, rust, and
debris, which can clog the nozzle and affect combustion efficiency.
2. Which type of oil burner is most commonly used in residential heating
systems?
A. Two-stage vaporizing burner
B. Pressure-atomizing burner
C. Rotary cup burner
D. Air-assisted atomizing burner
Answer: B
Rationale: Pressure-atomizing burners are common in residential
systems because they provide reliable, fine atomization and efficient
combustion.
3. What is the recommended operating temperature range for heating oil
in a storage tank?
A. 32–50°F
B. 90–120°F
C. 50–80°F
D. 100–150°F
Answer: C
, Rationale: Heating oil should be stored at moderate temperatures to
prevent waxing and maintain proper flow without risk of vaporization.
4. What is the function of the nozzle in an oil burner?
A. To control oil pressure
B. To filter impurities
C. To atomize the fuel into fine droplets for combustion
D. To regulate airflow
Answer: C
Rationale: The nozzle sprays the fuel oil as a fine mist, which ensures
efficient and complete combustion.
5. Which device in an oil heating system ignites the fuel-air mixture?
A. Oil filter
B. Ignition transformer and electrodes
C. Fan motor
D. Pressure regulator
Answer: B
Rationale: The ignition transformer produces a high-voltage spark at
the electrodes to ignite the atomized oil.
6. What is the purpose of a cad cell in an oil burner?
A. To measure oil temperature
B. To control airflow
C. To sense the flame and ensure safe operation
D. To regulate pressure
Answer: C
Rationale: The cadmium cell (cad cell) detects the presence of a flame
and signals the burner control to maintain safe operation.
7. What safety device shuts off the oil supply if the flame goes out?
A. Thermal fuse
B. Primary control with safety lockout
C. Pressure switch
D. Expansion tank
Answer: B
Rationale: Primary controls with safety lockout prevent oil from
flowing when there is no flame, avoiding fuel accumulation and fire
hazards.
8. Which factor has the greatest effect on combustion efficiency?
A. Oil storage temperature
, B. Air-to-fuel ratio
C. Nozzle size
D. Tank material
Answer: B
Rationale: Proper air-to-fuel ratio is critical for complete combustion;
too much or too little air reduces efficiency.
9. What is the standard color code for No. 2 heating oil?
A. Green
B. Red
C. Blue
D. Yellow
Answer: B
Rationale: No. 2 heating oil is typically dyed red to distinguish it from
diesel fuel and prevent misuse.
10. Which of the following is a common cause of smoky flames in
oil burners?
A. Dirty nozzle or improper air setting
B. High oil temperature
C. Too much combustion air
D. Excessive nozzle pressure
Answer: A
Rationale: A dirty nozzle or incorrect air adjustment leads to
incomplete combustion, producing smoke.
11. What is the purpose of the stack or chimney in an oil heating
system?
A. To heat the building
B. To vent combustion products safely outdoors
C. To regulate oil pressure
D. To filter air
Answer: B
Rationale: The chimney safely directs combustion gases, including
carbon monoxide, out of the building.
12. Which type of control maintains water temperature in an oil-fired
boiler?
A. Oil filter
B. Aquastat
C. Cad cell
