MINNESOTA SPECIAL ENGINEER BOILER LICENSE EXAM LATEST VERSIONS 2025/2026
(VERSION A AND B) ACTUAL EXAM COMPLETE 200 QUESTIONS AND CORRECT DETAILED
ANSWERS
Question 1
For the purpose of rating boiler horsepower for a Minnesota Engineer's License, how many
square feet of boiler heating surface is equivalent to one boiler horsepower?
A) 1 square foot
B) 5 square feet
C) 10 square feet
D) 12 square feet
E) 15 square feet
Correct Answer: C) 10 square feet
Rationale: According to Minnesota state boiler statutes, for licensing purposes, 10 square
feet of heating surface is the standard measurement used to calculate one boiler
horsepower.
Question 2
What is the maximum steam or vapor pressure at which a "Low Pressure Boiler" can operate?
A) 5 psig
B) 10 psig
C) 15 psig
D) 100 psig
E) 160 psig
Correct Answer: C) 15 psig
Rationale: By definition, a low-pressure steam boiler is designed to operate at a pressure not
exceeding 15 pounds per square inch gauge (psig).
Question 3
A hot water boiler is classified as "Low Pressure" as long as it does not exceed which of the
following parameters?
A) 100 psig or 180°F
B) 120 psig or 200°F
C) 160 psig or 250°F
D) 200 psig or 300°F
E) 250 psig or 350°F
Correct Answer: C) 160 psig or 250°F
Rationale: In Minnesota, a low-pressure hot water heating boiler is limited to a maximum
pressure of 160 psig and a maximum temperature of 250 degrees Fahrenheit.
Question 4
A person holding a current State of Minnesota Special Engineer license is permitted to be in
charge of a high or low-pressure plant up to what maximum total horsepower?
, 2
A) 30 horsepower
B) 50 horsepower
C) 100 horsepower
D) 200 horsepower
E) 500 horsepower
Correct Answer: B) 50 horsepower
Rationale: The Special Engineer license allows the holder to be the chief engineer in charge
of a boiler plant that does not exceed a total of 50 boiler horsepower.
Question 5
What is the maximum size plant in which a Special Engineer may act as a "Shift Engineer"?
A) 50 horsepower
B) 75 horsepower
C) 100 horsepower
D) 150 horsepower
E) 250 horsepower
Correct Answer: C) 100 horsepower
Rationale: While restricted to 50 HP as a chief engineer, a Special Engineer is authorized to
serve as a shift engineer in a plant with a capacity of up to 100 boiler horsepower.
Question 6
Under what conditions can a Special Engineer serve as an apprentice in a boiler plant larger than
100 horsepower?
A) Only if the plant is low pressure
B) Only on weekends
C) Under the direct supervision of a properly licensed engineer
D) After five years of experience
E) Apprenticeship is never allowed for Special Engineers
Correct Answer: C) Under the direct supervision of a properly licensed engineer
Rationale: Minnesota rules allow a Special Engineer to work as an apprentice in any size
plant, regardless of horsepower or pressure, as long as a higher-licensed engineer provides
direct supervision.
Question 7
What is the primary purpose of a low water fuel cut-out (LWCO)?
A) To increase steam pressure
B) To vent air from the system
C) To shut off the burner when a low water condition exists
D) To measure the temperature of the water
E) To automatically refill the boiler
Correct Answer: C) To shut off the burner when a low water condition exists
, 3
Rationale: The LWCO is a critical safety device designed to protect the boiler from "dry
firing," which occurs when the burner continues to operate without sufficient water,
potentially melting or exploding the pressure vessel.
Question 8
Which valve is responsible for relieving all excess pressure to prevent a boiler explosion?
A) Gate valve
B) Check valve
C) Safety valve or ASME safety relief valve
D) Globe valve
E) Vent valve
Correct Answer: C) Safety valve or ASME safety relief valve
Rationale: Safety valves (for steam) and safety relief valves (for hot water) are the final line
of defense, designed to open and vent pressure if the system exceeds its safe operating limit.
Question 9
On which type of system would you expect to find a "Tri-indicator" (Triple Gauge)?
A) High pressure steam boiler
B) Low pressure steam boiler
C) Hot water boiler
D) Refrigeration system
E) Fuel oil tank
Correct Answer: C) Hot water boiler
Rationale: Hot water boilers use a tri-indicator to provide the three most critical pieces of
data for water-based heating: temperature, pressure, and altitude.
Question 10
A tri-indicator informs the boiler operator of which three specific values?
A) Steam pressure, water level, and fuel flow
B) Temperature, Pressure (PSIG), and Altitude (feet)
C) Air pressure, draft, and CO2 levels
D) Oil pressure, pump speed, and voltage
E) Return temp, supply temp, and flow rate
Correct Answer: B) Temperature, Pressure (PSIG), and Altitude (feet)
Rationale: The tri-indicator displays the water temperature, the system pressure in pounds
per square inch, and the altitude of the water in the system (height of the water column in
feet).
Question 11
What constitutes the destructive force during a steam or hot water boiler explosion?
A) The sound of the blast
(VERSION A AND B) ACTUAL EXAM COMPLETE 200 QUESTIONS AND CORRECT DETAILED
ANSWERS
Question 1
For the purpose of rating boiler horsepower for a Minnesota Engineer's License, how many
square feet of boiler heating surface is equivalent to one boiler horsepower?
A) 1 square foot
B) 5 square feet
C) 10 square feet
D) 12 square feet
E) 15 square feet
Correct Answer: C) 10 square feet
Rationale: According to Minnesota state boiler statutes, for licensing purposes, 10 square
feet of heating surface is the standard measurement used to calculate one boiler
horsepower.
Question 2
What is the maximum steam or vapor pressure at which a "Low Pressure Boiler" can operate?
A) 5 psig
B) 10 psig
C) 15 psig
D) 100 psig
E) 160 psig
Correct Answer: C) 15 psig
Rationale: By definition, a low-pressure steam boiler is designed to operate at a pressure not
exceeding 15 pounds per square inch gauge (psig).
Question 3
A hot water boiler is classified as "Low Pressure" as long as it does not exceed which of the
following parameters?
A) 100 psig or 180°F
B) 120 psig or 200°F
C) 160 psig or 250°F
D) 200 psig or 300°F
E) 250 psig or 350°F
Correct Answer: C) 160 psig or 250°F
Rationale: In Minnesota, a low-pressure hot water heating boiler is limited to a maximum
pressure of 160 psig and a maximum temperature of 250 degrees Fahrenheit.
Question 4
A person holding a current State of Minnesota Special Engineer license is permitted to be in
charge of a high or low-pressure plant up to what maximum total horsepower?
, 2
A) 30 horsepower
B) 50 horsepower
C) 100 horsepower
D) 200 horsepower
E) 500 horsepower
Correct Answer: B) 50 horsepower
Rationale: The Special Engineer license allows the holder to be the chief engineer in charge
of a boiler plant that does not exceed a total of 50 boiler horsepower.
Question 5
What is the maximum size plant in which a Special Engineer may act as a "Shift Engineer"?
A) 50 horsepower
B) 75 horsepower
C) 100 horsepower
D) 150 horsepower
E) 250 horsepower
Correct Answer: C) 100 horsepower
Rationale: While restricted to 50 HP as a chief engineer, a Special Engineer is authorized to
serve as a shift engineer in a plant with a capacity of up to 100 boiler horsepower.
Question 6
Under what conditions can a Special Engineer serve as an apprentice in a boiler plant larger than
100 horsepower?
A) Only if the plant is low pressure
B) Only on weekends
C) Under the direct supervision of a properly licensed engineer
D) After five years of experience
E) Apprenticeship is never allowed for Special Engineers
Correct Answer: C) Under the direct supervision of a properly licensed engineer
Rationale: Minnesota rules allow a Special Engineer to work as an apprentice in any size
plant, regardless of horsepower or pressure, as long as a higher-licensed engineer provides
direct supervision.
Question 7
What is the primary purpose of a low water fuel cut-out (LWCO)?
A) To increase steam pressure
B) To vent air from the system
C) To shut off the burner when a low water condition exists
D) To measure the temperature of the water
E) To automatically refill the boiler
Correct Answer: C) To shut off the burner when a low water condition exists
, 3
Rationale: The LWCO is a critical safety device designed to protect the boiler from "dry
firing," which occurs when the burner continues to operate without sufficient water,
potentially melting or exploding the pressure vessel.
Question 8
Which valve is responsible for relieving all excess pressure to prevent a boiler explosion?
A) Gate valve
B) Check valve
C) Safety valve or ASME safety relief valve
D) Globe valve
E) Vent valve
Correct Answer: C) Safety valve or ASME safety relief valve
Rationale: Safety valves (for steam) and safety relief valves (for hot water) are the final line
of defense, designed to open and vent pressure if the system exceeds its safe operating limit.
Question 9
On which type of system would you expect to find a "Tri-indicator" (Triple Gauge)?
A) High pressure steam boiler
B) Low pressure steam boiler
C) Hot water boiler
D) Refrigeration system
E) Fuel oil tank
Correct Answer: C) Hot water boiler
Rationale: Hot water boilers use a tri-indicator to provide the three most critical pieces of
data for water-based heating: temperature, pressure, and altitude.
Question 10
A tri-indicator informs the boiler operator of which three specific values?
A) Steam pressure, water level, and fuel flow
B) Temperature, Pressure (PSIG), and Altitude (feet)
C) Air pressure, draft, and CO2 levels
D) Oil pressure, pump speed, and voltage
E) Return temp, supply temp, and flow rate
Correct Answer: B) Temperature, Pressure (PSIG), and Altitude (feet)
Rationale: The tri-indicator displays the water temperature, the system pressure in pounds
per square inch, and the altitude of the water in the system (height of the water column in
feet).
Question 11
What constitutes the destructive force during a steam or hot water boiler explosion?
A) The sound of the blast
