NJ Blue Seal FINAL EXAM STUDY GUIDE
2026/2027 | 200 Accurate Questions
with Verified Correct Detailed Answers
|| 100% Guaranteed Pass Recent Version
EXAM OVERVIEW
The NJ Blue Seal is the Third Grade Stationary Engineer License issued by the
New Jersey Department of Labor and Workforce Development, Bureau of Boiler
and Pressure Vessel Compliance . This license authorizes holders to operate high-
pressure boilers and refrigeration systems. The exam covers boiler operation,
steam engineering, refrigeration principles, electrical systems, turbine
operation, and safety protocols.
SECTION 1: BOILER FUNDAMENTALS AND STEAM ENGINEERING (Questions 1–
40)
1. Why must alternators run at a constant speed?
A. To maintain voltage
B. To maintain frequency
C. To maintain current
D. To maintain resistance
Correct Answer: B
Rationale: Alternators must run at a constant speed to maintain frequency.
Frequency is directly proportional to the speed of rotation and the number of
poles. Any speed variation directly affects the frequency of the generated AC
power .
[Date] 1
,2. What does "h" represent in steam calculations?
A. The sum of latent heat and sensible heat
B. The sum of specific heat and latent heat
C. The sum of sensible heat only
D. The sum of latent heat only
Correct Answer: A
Rationale: In steam engineering, "h" represents the total heat or enthalpy, which
is the sum of the latent heat and the sensible heat of the steam .
3. What chemicals cause hard scale in a boiler?
A. Sodium chloride and potassium chloride
B. Calcium carbonate and magnesium carbonate
C. Calcium sulfate and sodium sulfate
D. Magnesium chloride and sodium bicarbonate
Correct Answer: B
Rationale: Hard scale in boilers is primarily caused by calcium carbonate and
magnesium carbonate. These minerals precipitate out of water when heated and
form a hard, insulating scale on boiler surfaces, reducing heat transfer efficiency
and potentially causing overheating .
4. What is the formula for finding the Factor of Evaporation (FE)?
A. FE = Hs - (Tfw - 32) / 970.3
B. FE = (Hs + Tfw) / 970.3
C. FE = Hs / 970.3
D. FE = (Tfw - 32) / Hs
Correct Answer: A
[Date] 2
,Rationale: The Factor of Evaporation is calculated as FE = Hs - (Tfw - 32) / 970.3,
where Hs is the heat of steam, Tfw is the temperature of feedwater, and 970.3 is
the latent heat of evaporation at standard conditions .
5. What is the minimum size of water column connections to a boiler?
A. 1/2 inch
B. 3/4 inch
C. 1 inch
D. 2 inches
Correct Answer: C
Rationale: The water column connections to a boiler must be a minimum of 1
inch in diameter to ensure proper water level indication and prevent clogging
from sediment and scale .
6. What is the formula for finding Boiler Horsepower (BHP)?
A. BHP = Ws / 34.5
B. BHP = Ws × 34.5
C. BHP = Ws / 970.3
D. BHP = Ws × 970.3
Correct Answer: A
Rationale: Boiler Horsepower is calculated using BHP = Ws / 34.5, where Ws is the
steam production in pounds per hour. One boiler horsepower equals the
evaporation of 34.5 pounds of water per hour at 212°F .
7. A 20,700 lbs. per hour boiler equals how many horsepower?
[Date] 3
, A. 500 HP
B. 600 HP
C. 700 HP
D. 800 HP
Correct Answer: B
Rationale: Using the formula BHP = Ws / 34.5: 20,.5 = 600 HP .
8. A boiler with 5,021,250 Btu's would equal how many HP?
A. 100 hp
B. 125 hp
C. 150 hp
D. 175 hp
Correct Answer: C
Rationale: One boiler horsepower equals 33,475 Btu/hr. 5,021,,475 = 150
hp .
9. What is the formula for finding the Heating Surface (Hs)?
A. Hs = Dia × 3.1416 × L × N / 144
B. Hs = Dia × L × N / 144
C. Hs = Dia × 3.1416 × L / 144
D. Hs = Dia × 3.1416 × N / 144
Correct Answer: A
Rationale: Heating Surface is calculated as Hs = Dia × 3.1416 × L × N / 144, where
Dia is the diameter of tubes, L is the length in inches, N is the number of tubes,
and 144 converts square inches to square feet .
[Date] 4
2026/2027 | 200 Accurate Questions
with Verified Correct Detailed Answers
|| 100% Guaranteed Pass Recent Version
EXAM OVERVIEW
The NJ Blue Seal is the Third Grade Stationary Engineer License issued by the
New Jersey Department of Labor and Workforce Development, Bureau of Boiler
and Pressure Vessel Compliance . This license authorizes holders to operate high-
pressure boilers and refrigeration systems. The exam covers boiler operation,
steam engineering, refrigeration principles, electrical systems, turbine
operation, and safety protocols.
SECTION 1: BOILER FUNDAMENTALS AND STEAM ENGINEERING (Questions 1–
40)
1. Why must alternators run at a constant speed?
A. To maintain voltage
B. To maintain frequency
C. To maintain current
D. To maintain resistance
Correct Answer: B
Rationale: Alternators must run at a constant speed to maintain frequency.
Frequency is directly proportional to the speed of rotation and the number of
poles. Any speed variation directly affects the frequency of the generated AC
power .
[Date] 1
,2. What does "h" represent in steam calculations?
A. The sum of latent heat and sensible heat
B. The sum of specific heat and latent heat
C. The sum of sensible heat only
D. The sum of latent heat only
Correct Answer: A
Rationale: In steam engineering, "h" represents the total heat or enthalpy, which
is the sum of the latent heat and the sensible heat of the steam .
3. What chemicals cause hard scale in a boiler?
A. Sodium chloride and potassium chloride
B. Calcium carbonate and magnesium carbonate
C. Calcium sulfate and sodium sulfate
D. Magnesium chloride and sodium bicarbonate
Correct Answer: B
Rationale: Hard scale in boilers is primarily caused by calcium carbonate and
magnesium carbonate. These minerals precipitate out of water when heated and
form a hard, insulating scale on boiler surfaces, reducing heat transfer efficiency
and potentially causing overheating .
4. What is the formula for finding the Factor of Evaporation (FE)?
A. FE = Hs - (Tfw - 32) / 970.3
B. FE = (Hs + Tfw) / 970.3
C. FE = Hs / 970.3
D. FE = (Tfw - 32) / Hs
Correct Answer: A
[Date] 2
,Rationale: The Factor of Evaporation is calculated as FE = Hs - (Tfw - 32) / 970.3,
where Hs is the heat of steam, Tfw is the temperature of feedwater, and 970.3 is
the latent heat of evaporation at standard conditions .
5. What is the minimum size of water column connections to a boiler?
A. 1/2 inch
B. 3/4 inch
C. 1 inch
D. 2 inches
Correct Answer: C
Rationale: The water column connections to a boiler must be a minimum of 1
inch in diameter to ensure proper water level indication and prevent clogging
from sediment and scale .
6. What is the formula for finding Boiler Horsepower (BHP)?
A. BHP = Ws / 34.5
B. BHP = Ws × 34.5
C. BHP = Ws / 970.3
D. BHP = Ws × 970.3
Correct Answer: A
Rationale: Boiler Horsepower is calculated using BHP = Ws / 34.5, where Ws is the
steam production in pounds per hour. One boiler horsepower equals the
evaporation of 34.5 pounds of water per hour at 212°F .
7. A 20,700 lbs. per hour boiler equals how many horsepower?
[Date] 3
, A. 500 HP
B. 600 HP
C. 700 HP
D. 800 HP
Correct Answer: B
Rationale: Using the formula BHP = Ws / 34.5: 20,.5 = 600 HP .
8. A boiler with 5,021,250 Btu's would equal how many HP?
A. 100 hp
B. 125 hp
C. 150 hp
D. 175 hp
Correct Answer: C
Rationale: One boiler horsepower equals 33,475 Btu/hr. 5,021,,475 = 150
hp .
9. What is the formula for finding the Heating Surface (Hs)?
A. Hs = Dia × 3.1416 × L × N / 144
B. Hs = Dia × L × N / 144
C. Hs = Dia × 3.1416 × L / 144
D. Hs = Dia × 3.1416 × N / 144
Correct Answer: A
Rationale: Heating Surface is calculated as Hs = Dia × 3.1416 × L × N / 144, where
Dia is the diameter of tubes, L is the length in inches, N is the number of tubes,
and 144 converts square inches to square feet .
[Date] 4
