Download Minnesota Special Engineer Boiler License Exam 2025/2026 Study Questions And Answers and more Exams Engineering in PDF only on Docsity!
Minnesota Special Engineer Boiler License Exam
2025 /2026 Study Questions And Answers
Special (License Grade) Work in any type of plant Grade C (License Grade) Can operate low-pressure steam or hot water (no steam engines/turbines) Grade B (License Grade) Can operate high-pressure or low-pressure steam or hot water (no steam engines/turbines) Grade A (License Grade) Can operate any plant including plants with steam engines/turbines Special (License Class) Take Charge (max 50 hpr) Shift Engineer (max 100 hpr)
2nd Class (License Class) Take Charge (max 100 hpr) Shift Engineer (max 500 hpr) 1st Class (License Class) Take Charge (max 500 hpr) Shift Engineer (unlimited hpr) Chief (License Class) Take Charge (unlimited hpr) Shift engineer (unlimited hpr) Shift Engineer Can operate and take responsibility for the plant while on duty Take Charge You are the main person in charge of the plant. You supervise shift engineers. 1 boiler horsepower =
Above 15 psi, above 160 psi water, and temps above 250°F A high pressure boiler is classified as such when what -? A.S.M.E. Approved What type of safety valve is required? Efficiency When operating a boiler, what is most important? Shuts off fuel in case of low water How does a low water fuel cut off (LWCO) protect a boiler? shut off the burner when a low water condition exists. If you cannot determine water level what do you do? No Can you compress a liquid?
Cast Iron Sectional and Firebox What boilers are low pressure only? Push nipples and Tie Rods What holds cast iron sections together? At least as big as the largest incoming wire On electric boilers, how large should the ground wire be? Baffle Directs flow of combustion gasses, water, and/or steam Passes Amount of times the heat moves through the tubes in a fire tube boiler Refractory Hard surface insulation (brick, concrete,...)
What prevents thermal shock in a hydronic system? Cast iron section boiler Inexpensive Corrosion resistance Brittle Low pressure only Comes in sections Firetube boilers Used for small to medium plants Fire inside tubes, water outside Measure by amount of heat transfer surface Scotch Marine The HRT (horizontal return tubular) Locomotive Vertical firetube Firebox What are five types of firetube boilers?
Scotch Marine Internal furnace Furnace made of corrugated tube (Morrison tube) Can be wetback or dryback Wetback More efficient Water jacketed Harder to perform maintenance Dryback Less efficient Refractory backed Easier to maintenance Gas flames What flames are generally blue? Oil flames What flames are white-ish/yellow?
They are expanded at the ends to support tube sheet then flared or beaded How are firetubes held in place? Watertube boilers Two (2) or more pressure vessels connected by tubes Water inside tubes A, D, O What are the common types of watertube boilers? Removes sludge Control chemistry Control water level Can drain the boiler What are reasons for a blowdown? Breeching Connects boiler to the stack
Economizer (preheats feed water) Air preheater (preheats combustion air) What are two types of heat exchangers? Less than five (5) turns How many turns equals a quick valve? Quick valve Which valve do you open first and shut last? Two (2) valves How many bottom blowdown valves are needed for pressures over 100 pounds? 150 degrees Fahrenheit What is the max temperature you can send water down the sewer? Steam drum on top Mud drum on bottom In a watertube boiler, which pressure drum is on top and which is on bottom?
Condensing What does lowering the stack temperatures far enough called? Hot water boilers (hydronic) Can be fire tube, water tube, or cast iron Can add Glycol or Dow Therm to reduce corrosion High temperatures and low pressures What conditions do Glycol and Dow Therm like? Safety valve What is the most important valve on a steam boiler? Temperature, pressure, and altitude What does a tri-indicator gauge measure? Constant Mass =
Gravity Weight = Pounds per hour (PPH) What units is steam measure in? Density Temperature differences cause _________ differences which drives natural circulation One How many pounds of water make one (1) pound of steam? Temperature Measure how fast the molecules are moving Heat Quantity (measure how fast and how many)
Breeching or stack temperatures What are good indications of boiler efficiency? Optical Pyrometer What can measure extremely high temperatures? Sensible heat The heat we can feel Latent heat The energy absorbed or released during a change in state Conduction, convection, and radiation What are the three (3) types of heat transfer? Conduction Transfer of heat through direct contact Convection
Heat transferred by movement of air or fluids (like our pizza) Radiation Heat transferred by waves (electromagnetic) The pressure goes up If temperature goes up, what does pressure do? Using the evaporative capacity (34.5 pph) How can you measure the actual boiler horsepower? Power out divided by power in (PO/PI) How do you calculate boiler efficiency? Wet saturated steam Saturated steam = wet steam = Forced, induced, and natural What are the three (3) types of draft?
Atomized What must all oils be? Heated What must heavy oils be? Fuel, heat, and oxygen What three (3) do you need to sustain combustion? CO What is a byproduct of a complete combustion? CO and soot What is a byproduct of incomplete combustion? Insufficient oxygen or too much fuel What causes incomplete combustion?
Incomplete combustion Low fuel oil temperatures will cause what? Rate Primary air controls what? How complete the combustion is Secondary air controls what? Complete combustion Excess air ensures what? Steam, air, and mechanical What are three (3) ways to atomize fuel oils? 150,000 BTUs per gallon What is #6 fuel oil rated at? Lowers the viscosity (easier to pour)
