Page 1 of 149
OIL BURNER LICENSE EXAM AND PRACTICE
EXAM NEWEST ACTUAL EXAM COMPLETE
70 QUESTIONS AND CORRECT ANSWERS
(VERIFIED ANSWERS) ||COMPLETE A+
GUIDE
1. The ideal air-to-fuel ratio for complete combustion of No. 2
fuel oil by weight is approximately:
A) 5:1
B) 10:1
C) 15:1
D) 20:1
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Answer: C
Rationale: Complete combustion of No. 2 oil requires about
14.5–15 lbs of air per lb of fuel.
2. Which gas indicates incomplete combustion in an oil burner
flue?
A) O₂
B) CO₂
C) CO
D) N₂
Answer: C
Rationale: CO forms when oxygen is insufficient. It is toxic and
indicates inefficiency.
3. Scenario: You measure 12% CO₂ and 50 ppm CO in the
stack. What should you do first?
A) Increase combustion air
B) Decrease combustion air
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C) Increase fuel pressure
D) Replace the nozzle
Answer: A
Rationale: CO indicates incomplete combustion. Increase air to
lower CO.
4. The three elements required for combustion are:
A) Fuel, oxygen, spark
B) Fuel, heat, oxygen
C) Fuel, nitrogen, heat
D) Oxygen, heat, carbon
Answer: B
Rationale: Fire triangle = fuel, oxygen, heat.
5. Excess air in an oil burner typically ranges between:
A) 0–10%
B) 15–50%
C) 60–80%
D) 100–150%
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Answer: B
Rationale: 15–50% excess air ensures complete combustion
without excessive heat loss.
6. What is the primary purpose of draft over the fire?
A) Cool the combustion chamber
B) Remove combustion gases and supply air
C) Increase flame temperature
D) Reduce fuel consumption
Answer: B
Rationale: Draft removes products of combustion and supplies
fresh air.
7. Which of the following will cause a puffback?
A) High draft
B) Delayed ignition
C) Low stack temperature
D) High CO₂
OIL BURNER LICENSE EXAM AND PRACTICE
EXAM NEWEST ACTUAL EXAM COMPLETE
70 QUESTIONS AND CORRECT ANSWERS
(VERIFIED ANSWERS) ||COMPLETE A+
GUIDE
1. The ideal air-to-fuel ratio for complete combustion of No. 2
fuel oil by weight is approximately:
A) 5:1
B) 10:1
C) 15:1
D) 20:1
,Page 2 of 149
Answer: C
Rationale: Complete combustion of No. 2 oil requires about
14.5–15 lbs of air per lb of fuel.
2. Which gas indicates incomplete combustion in an oil burner
flue?
A) O₂
B) CO₂
C) CO
D) N₂
Answer: C
Rationale: CO forms when oxygen is insufficient. It is toxic and
indicates inefficiency.
3. Scenario: You measure 12% CO₂ and 50 ppm CO in the
stack. What should you do first?
A) Increase combustion air
B) Decrease combustion air
,Page 3 of 149
C) Increase fuel pressure
D) Replace the nozzle
Answer: A
Rationale: CO indicates incomplete combustion. Increase air to
lower CO.
4. The three elements required for combustion are:
A) Fuel, oxygen, spark
B) Fuel, heat, oxygen
C) Fuel, nitrogen, heat
D) Oxygen, heat, carbon
Answer: B
Rationale: Fire triangle = fuel, oxygen, heat.
5. Excess air in an oil burner typically ranges between:
A) 0–10%
B) 15–50%
C) 60–80%
D) 100–150%
, Page 4 of 149
Answer: B
Rationale: 15–50% excess air ensures complete combustion
without excessive heat loss.
6. What is the primary purpose of draft over the fire?
A) Cool the combustion chamber
B) Remove combustion gases and supply air
C) Increase flame temperature
D) Reduce fuel consumption
Answer: B
Rationale: Draft removes products of combustion and supplies
fresh air.
7. Which of the following will cause a puffback?
A) High draft
B) Delayed ignition
C) Low stack temperature
D) High CO₂
