Page 1 of 125
Maryland Stationary Engineer Grade 1
Exam ACTUAL QUESTIONS AND ANSWERS
LATEST UPDATE THIS YEAR
Summarized Exam Coverage – Maryland Stationary Engineer Grade 1
The Maryland Stationary Engineer Grade 1 license exam (administered by the Board of Boiler Rules,
under the Maryland Department of Labor) covers:
• Boiler Types & Construction: Firetube (Scotch marine, HRT), watertube (D-type, A-type, O-type),
electric, cast iron. ASME Section I (Power Boilers) vs Section IV (Heating Boilers). High pressure
(>15 psi steam, >160 psi water).
• Combustion & Fuels: Gas, oil, coal, waste heat. Burners (atomizing, vaporizing), flame
safeguards, combustion controls (O₂ trim, excess air), draft (natural, forced, induced, balanced).
Efficiency calculations.
• Water Treatment & Chemistry: Scale, corrosion, carryover, priming, foaming. External
treatment (zeolite softeners, demineralizers, reverse osmosis). Internal treatment (phosphates,
chelants, sulfite, caustic). Blowdown (bottom, surface). Conductivity, pH, alkalinity, dissolved
oxygen control.
• Boiler Operation & Safety: Starting, warming up, shutting down. Water level control (gauge
glass, try cocks). Low-water fuel cutoff (LWCO), safety valves (ASME, set pressure, popping
point, blowdown). Hydrostatic testing. Boiler logbooks.
• Steam Systems: Piping, valves (gate, globe, check, safety relief), steam traps (float,
thermostatic, thermodynamic, inverted bucket). Condensate return, flash steam, water hammer
prevention. Steam separators, superheaters, desuperheaters.
• Feedwater Systems: Pumps (centrifugal, reciprocating, turbine-driven). Deaerators, feedwater
heaters, economizers. Feedwater regulators.
• Auxiliaries & Power Plant Systems: Air compressors, cooling towers, chillers, generators,
turbines, condensers, pumps, fans. Instrumentation & controls (pressure, temperature, flow,
level). SCADA, DCS.
• Maintenance & Inspection: Internal/external inspections (by insurance inspector or Board).
Tube leaks, refractory repair, soot blowing (manual, automatic). Lay-up (wet, dry).
Nondestructive testing.
• Safety & Regulations: Boiler room safety, PPE, lockout/tagout, confined space entry, hot work
permits. Boiler room logbook. Maryland Boiler Rules (COMAR 09.12.06). ASME, NBIC, NFPA.
• Math & Calculations: Steam tables, horsepower conversion, BTU, evaporation rate (from and at
212°F), fuel consumption, boiler efficiency, feedwater flow, blowdown rate, pipe sizing, heat
transfer.
, Page 2 of 125
1. A high-pressure boiler is operating at 200 psi. The safety valve on the boiler is set to open at 210 psi.
At what pressure must the safety valve begin to open (pop) and be fully open, per ASME Code?
A) Begin to open at 210 psi; fully open at 215 psi
B) Begin to open at 200 psi; fully open at 210 psi
C) Begin to open at 210 psi; fully open at no more than 6% above set pressure (approximately 222 psi)
D) Begin to open at 215 psi; fully open at 225 psi
*Answer: C — ASME Code requires safety valves to be set at or below MAWP and to be fully open at a
pressure not exceeding 6% above the set pressure. For 210 psi, 6% of 210 = 12.6 psi, so 222.6 psi max.*
2. The low-water fuel cutoff (LWCO) trips and shuts down the burner. The operator checks the gauge
glass and sees the water level is at the normal operating level. What is the most likely cause of the false
trip?
A) The burner is oversized
B) The LWCO float is stuck in the down position or the electrode is fouled
C) The steam pressure is too low
D) The safety valve is leaking
, Page 3 of 125
Answer: B — A false LWCO trip can be caused by a stuck float, a plugged equalizer line, or a failed
electrode, giving a low-water signal even when the water level is normal.
3. Which type of steam trap uses a bimetallic element to open and close based on temperature
difference, and is often used on superheated steam lines?
A) Float and thermostatic trap
B) Inverted bucket trap
C) Thermostatic (bimetallic) trap
D) Thermodynamic (disc) trap
Answer: C — Bimetallic thermostatic traps are used on superheated steam lines because they can
withstand high temperatures without damage, unlike bellows traps.
4. A watertube boiler tube bursts, and steam is blowing into the furnace. The operator should
immediately:
A) Add more feedwater to cool the remaining tubes
B) Shut off the fuel supply, shut off forced draft, and secure the feedwater; then safely relieve pressure
C) Increase the draft to blow the steam out of the stack
D) Continue operating at reduced load
, Page 4 of 125
Answer: B — A tube rupture is an emergency; the fuel must be cut off, draft stopped, and the fire
extinguished. Adding cold water could cause thermal shock and more ruptures.
5. An operator notices that the stack temperature is 600°F, but the normal operating stack temperature
is 450°F. The boiler load is the same. What is the most likely cause of the high stack temperature?
A) The burner air/fuel ratio is too rich (excess fuel)
B) The boiler heating surfaces are fouled with soot or scale, reducing heat transfer
C) The combustion air temperature is too low
D) The steam pressure is too high
Answer: B — Soot on the fireside or scale on the waterside insulates the heat transfer surfaces, causing
higher flue gas temperature.
6. A steam line is hammering loudly. What is the most likely cause and corrective action?
A) Superheated steam; reduce temperature
B) Condensate accumulation in the line; open drains and traps, and ensure proper steam line warming
procedure
C) The steam pressure is too high; reduce pressure
D) Air in the line; vent the line
Maryland Stationary Engineer Grade 1
Exam ACTUAL QUESTIONS AND ANSWERS
LATEST UPDATE THIS YEAR
Summarized Exam Coverage – Maryland Stationary Engineer Grade 1
The Maryland Stationary Engineer Grade 1 license exam (administered by the Board of Boiler Rules,
under the Maryland Department of Labor) covers:
• Boiler Types & Construction: Firetube (Scotch marine, HRT), watertube (D-type, A-type, O-type),
electric, cast iron. ASME Section I (Power Boilers) vs Section IV (Heating Boilers). High pressure
(>15 psi steam, >160 psi water).
• Combustion & Fuels: Gas, oil, coal, waste heat. Burners (atomizing, vaporizing), flame
safeguards, combustion controls (O₂ trim, excess air), draft (natural, forced, induced, balanced).
Efficiency calculations.
• Water Treatment & Chemistry: Scale, corrosion, carryover, priming, foaming. External
treatment (zeolite softeners, demineralizers, reverse osmosis). Internal treatment (phosphates,
chelants, sulfite, caustic). Blowdown (bottom, surface). Conductivity, pH, alkalinity, dissolved
oxygen control.
• Boiler Operation & Safety: Starting, warming up, shutting down. Water level control (gauge
glass, try cocks). Low-water fuel cutoff (LWCO), safety valves (ASME, set pressure, popping
point, blowdown). Hydrostatic testing. Boiler logbooks.
• Steam Systems: Piping, valves (gate, globe, check, safety relief), steam traps (float,
thermostatic, thermodynamic, inverted bucket). Condensate return, flash steam, water hammer
prevention. Steam separators, superheaters, desuperheaters.
• Feedwater Systems: Pumps (centrifugal, reciprocating, turbine-driven). Deaerators, feedwater
heaters, economizers. Feedwater regulators.
• Auxiliaries & Power Plant Systems: Air compressors, cooling towers, chillers, generators,
turbines, condensers, pumps, fans. Instrumentation & controls (pressure, temperature, flow,
level). SCADA, DCS.
• Maintenance & Inspection: Internal/external inspections (by insurance inspector or Board).
Tube leaks, refractory repair, soot blowing (manual, automatic). Lay-up (wet, dry).
Nondestructive testing.
• Safety & Regulations: Boiler room safety, PPE, lockout/tagout, confined space entry, hot work
permits. Boiler room logbook. Maryland Boiler Rules (COMAR 09.12.06). ASME, NBIC, NFPA.
• Math & Calculations: Steam tables, horsepower conversion, BTU, evaporation rate (from and at
212°F), fuel consumption, boiler efficiency, feedwater flow, blowdown rate, pipe sizing, heat
transfer.
, Page 2 of 125
1. A high-pressure boiler is operating at 200 psi. The safety valve on the boiler is set to open at 210 psi.
At what pressure must the safety valve begin to open (pop) and be fully open, per ASME Code?
A) Begin to open at 210 psi; fully open at 215 psi
B) Begin to open at 200 psi; fully open at 210 psi
C) Begin to open at 210 psi; fully open at no more than 6% above set pressure (approximately 222 psi)
D) Begin to open at 215 psi; fully open at 225 psi
*Answer: C — ASME Code requires safety valves to be set at or below MAWP and to be fully open at a
pressure not exceeding 6% above the set pressure. For 210 psi, 6% of 210 = 12.6 psi, so 222.6 psi max.*
2. The low-water fuel cutoff (LWCO) trips and shuts down the burner. The operator checks the gauge
glass and sees the water level is at the normal operating level. What is the most likely cause of the false
trip?
A) The burner is oversized
B) The LWCO float is stuck in the down position or the electrode is fouled
C) The steam pressure is too low
D) The safety valve is leaking
, Page 3 of 125
Answer: B — A false LWCO trip can be caused by a stuck float, a plugged equalizer line, or a failed
electrode, giving a low-water signal even when the water level is normal.
3. Which type of steam trap uses a bimetallic element to open and close based on temperature
difference, and is often used on superheated steam lines?
A) Float and thermostatic trap
B) Inverted bucket trap
C) Thermostatic (bimetallic) trap
D) Thermodynamic (disc) trap
Answer: C — Bimetallic thermostatic traps are used on superheated steam lines because they can
withstand high temperatures without damage, unlike bellows traps.
4. A watertube boiler tube bursts, and steam is blowing into the furnace. The operator should
immediately:
A) Add more feedwater to cool the remaining tubes
B) Shut off the fuel supply, shut off forced draft, and secure the feedwater; then safely relieve pressure
C) Increase the draft to blow the steam out of the stack
D) Continue operating at reduced load
, Page 4 of 125
Answer: B — A tube rupture is an emergency; the fuel must be cut off, draft stopped, and the fire
extinguished. Adding cold water could cause thermal shock and more ruptures.
5. An operator notices that the stack temperature is 600°F, but the normal operating stack temperature
is 450°F. The boiler load is the same. What is the most likely cause of the high stack temperature?
A) The burner air/fuel ratio is too rich (excess fuel)
B) The boiler heating surfaces are fouled with soot or scale, reducing heat transfer
C) The combustion air temperature is too low
D) The steam pressure is too high
Answer: B — Soot on the fireside or scale on the waterside insulates the heat transfer surfaces, causing
higher flue gas temperature.
6. A steam line is hammering loudly. What is the most likely cause and corrective action?
A) Superheated steam; reduce temperature
B) Condensate accumulation in the line; open drains and traps, and ensure proper steam line warming
procedure
C) The steam pressure is too high; reduce pressure
D) Air in the line; vent the line
