2026 UPDATED QUESTIONS DOWNLOAD
Maryland Stationary Engineer Grade 1 Actual Exam Prep | 400+
Q&A with Rationales | Chief Engineer Level Certification Review
Prepare for the Maryland Grade 1 Stationary Engineer license with this comprehensive bank of 400
high-yield practice questions and detailed italicized rationales. This study guide covers advanced plant
management, including high-pressure boiler operations, large-scale ammonia refrigeration (R-
717), steam turbines, and Maryland state-specific safety codes. Master the critical technical
knowledge and plant leadership skills required at the Chief Engineer level to pass the PSI/State board
exam on your first attempt.
1. A "Hartford Loop" is primarily used on low-pressure steam boilers to prevent:
A. Excessive steam pressure.
B. Water from leaving the boiler in case of a return line break.
C. Scaling in the heat exchanger.
D. High stack temperatures.
Rationale: B. The Hartford Loop is a piping arrangement that prevents the boiler water level
from dropping below the safe lowest visible part of the gauge glass if a leak occurs in the
condensate return line.
2. Which valve is considered the most important fitting on a high-pressure steam
boiler?
A. The main steam stop valve.
B. The bottom blowdown valve.
C. The safety valve.
D. The feedwater check valve.
Rationale: C. The safety valve is the primary overpressure protection device; it must be
capable of discharging all the steam the boiler can generate without allowing pressure to rise
more than 6% above the MAWP.
3. In a large centrifugal chiller, the "Purge Unit" is designed to remove:
A. Excess refrigerant.
B. Oil from the evaporator.
C. Non-condensable gases and moisture.
D. Scale from the condenser tubes.
Rationale: C. Purge units are used on low-pressure chillers (like R-123) because they operate
in a vacuum; any leaks pull in air (non-condensables) which must be removed to maintain
efficiency.
4. What is the standard "Flash Point" of No. 2 fuel oil?
A. 100°F.
B. 115°F.
, 2026 UPDATED QUESTIONS DOWNLOAD
C. 150°F.
D. 200°F.
Rationale: A. The flash point is the lowest temperature at which a liquid produces enough
vapor to form an ignitable mixture; for No. 2 oil, the legal minimum is typically 100°F.
5. A "Steam Turbine" hunting (constant speed fluctuation) is usually caused by a
malfunction in the:
A. Lubrication system.
B. Condenser vacuum.
C. Governor system.
D. Exhaust head.
Rationale: C. The governor regulates the steam flow to maintain a constant RPM; "hunting"
indicates the governor is overcorrecting or sticking.
6. Maryland Law requires that a Grade 1 Stationary Engineer be present in a plant
where:
A. The boiler is over 30 HP.
B. The plant exceeds 500 total horsepower or large-tonnage refrigeration.
C. Any high-pressure steam is generated.
D. There is only one employee on shift.
Rationale: B. Grade 1 engineers are required for high-capacity plants (unlimited HP) to ensure
public safety in high-pressure environments.
7. Which type of pump is "Positive Displacement"?
A. Centrifugal pump.
B. Reciprocating pump.
C. Regenerative turbine pump.
Rationale: B. Reciprocating (piston) and gear pumps are positive displacement, meaning they
move a specific volume of fluid per stroke regardless of pressure.
8. "Saponification" in a boiler is caused by the reaction of high alkalinity with:
A. Scale.
B. Dissolved oxygen.
C. Fats and oils.
D. Nitrogen.
Rationale: C. When oil enters the boiler water, it reacts with alkaline chemicals to form soap,
leading to foaming and carryover.
9. A "Synchronous Motor" can be used to correct "Power Factor" by:
A. Increasing the voltage.
B. Over-exciting the DC field.
C. Reducing the frequency.
D. Running it in reverse.
, 2026 UPDATED QUESTIONS DOWNLOAD
Rationale: B. By over-exciting the field, the motor acts as a capacitor, which compensates for
the lagging power factor caused by induction motors in the plant.
10. What is the maximum "MAWP" allowed for a boiler constructed with "Lap-Seam"
longitudinal joints?
A. 15 psi.
B. 100 psi.
C. 150 psi.
D. 250 psi.
Rationale: A. Lap-seam boilers are considered dangerous at high pressures due to stress
concentrations; most jurisdictions (including MD) limit them to low pressure (15 psi) if they are
over 30 years old.
11. The "Latent Heat of Evaporation" for water at atmospheric pressure is:
A. 144 BTU.
B. 180 BTU.
C. 970.3 BTU.
D. 1150 BTU.
Rationale: C. It takes 970.3 BTUs to change 1 lb of water at 212°F to 1 lb of steam at 212°F.
12. In a refrigeration cycle, the "Expansion Valve" is located between the:
A. Compressor and Condenser.
B. Condenser and Evaporator.
C. Evaporator and Compressor.
D. Receiver and Compressor.
Rationale: B. The expansion valve (metering device) drops the pressure of the liquid
refrigerant before it enters the evaporator.
13. A "Closed Feedwater Heater" uses what to heat the water?
A. Direct mixing of steam and water.
B. Steam in a shell-and-tube heat exchanger.
C. Electricity.
D. Hot flue gases.
Rationale: B. In a closed heater, the steam and water do not mix; an "Open" heater (like a
Deaerator) mixes them directly.
14. What is the primary purpose of a "Steam Trap"?
A. To trap steam for later use.
B. To remove air and condensate without wasting steam.
C. To increase the pressure in the header.
D. To prevent water hammer in the boiler tubes.
Rationale: B. Traps are automatic valves that discharge condensate and air from steam lines
to maintain dry steam and prevent water hammer.
, 2026 UPDATED QUESTIONS DOWNLOAD
15. "Alkalinity" in boiler water is typically measured using:
A. A thermometer.
B. A titration test (pH or P/M alkalinity).
C. A hydrometer.
D. A pressure gauge.
Rationale: B. Proper alkalinity prevents corrosion but must be controlled to prevent foaming.
16. A "Surface Blowdown" is used to remove:
A. Sludge from the mud drum.
B. Dissolved solids and oils from the water's surface.
C. Air from the steam space.
D. Soot from the tubes.
Rationale: B. Surface blows control the "Total Dissolved Solids" (TDS) and prevent
foaming/priming.
17. If a safety valve on a high-pressure boiler is set at 150 psi, what is the minimum
required "Blowback"?
A. 1 psi.
B. 2 psi (or 2% of set pressure).
C. 10 psi.
D. 25 psi.
Rationale: B. Blowback is the difference between the popping pressure and the closing
pressure; ASME code specifies minimums to prevent "chattering" of the valve.
18. "Caustic Embrittlement" is a form of corrosion caused by:
A. High oxygen levels.
B. High concentrations of sodium hydroxide (caustic soda).
C. Low water level.
D. High steam velocity.
Rationale: B. This causes the metal to become brittle and crack, usually at seams or rivets.
19. A "Centrifugal Pump" should be started with the discharge valve:
A. Fully open.
B. Fully closed (to reduce starting load).
C. Halfway open.
D. Removed.
Rationale: B. Starting with the valve closed (or "throttled") reduces the starting torque/current
required by the motor.
20. What is the "Rupture Disk" on a low-pressure chiller (R-123) set to burst at?
A. 5 psi.
B. 15 psi.
C. 50 psi.
D. 150 psi.
Maryland Stationary Engineer Grade 1 Actual Exam Prep | 400+
Q&A with Rationales | Chief Engineer Level Certification Review
Prepare for the Maryland Grade 1 Stationary Engineer license with this comprehensive bank of 400
high-yield practice questions and detailed italicized rationales. This study guide covers advanced plant
management, including high-pressure boiler operations, large-scale ammonia refrigeration (R-
717), steam turbines, and Maryland state-specific safety codes. Master the critical technical
knowledge and plant leadership skills required at the Chief Engineer level to pass the PSI/State board
exam on your first attempt.
1. A "Hartford Loop" is primarily used on low-pressure steam boilers to prevent:
A. Excessive steam pressure.
B. Water from leaving the boiler in case of a return line break.
C. Scaling in the heat exchanger.
D. High stack temperatures.
Rationale: B. The Hartford Loop is a piping arrangement that prevents the boiler water level
from dropping below the safe lowest visible part of the gauge glass if a leak occurs in the
condensate return line.
2. Which valve is considered the most important fitting on a high-pressure steam
boiler?
A. The main steam stop valve.
B. The bottom blowdown valve.
C. The safety valve.
D. The feedwater check valve.
Rationale: C. The safety valve is the primary overpressure protection device; it must be
capable of discharging all the steam the boiler can generate without allowing pressure to rise
more than 6% above the MAWP.
3. In a large centrifugal chiller, the "Purge Unit" is designed to remove:
A. Excess refrigerant.
B. Oil from the evaporator.
C. Non-condensable gases and moisture.
D. Scale from the condenser tubes.
Rationale: C. Purge units are used on low-pressure chillers (like R-123) because they operate
in a vacuum; any leaks pull in air (non-condensables) which must be removed to maintain
efficiency.
4. What is the standard "Flash Point" of No. 2 fuel oil?
A. 100°F.
B. 115°F.
, 2026 UPDATED QUESTIONS DOWNLOAD
C. 150°F.
D. 200°F.
Rationale: A. The flash point is the lowest temperature at which a liquid produces enough
vapor to form an ignitable mixture; for No. 2 oil, the legal minimum is typically 100°F.
5. A "Steam Turbine" hunting (constant speed fluctuation) is usually caused by a
malfunction in the:
A. Lubrication system.
B. Condenser vacuum.
C. Governor system.
D. Exhaust head.
Rationale: C. The governor regulates the steam flow to maintain a constant RPM; "hunting"
indicates the governor is overcorrecting or sticking.
6. Maryland Law requires that a Grade 1 Stationary Engineer be present in a plant
where:
A. The boiler is over 30 HP.
B. The plant exceeds 500 total horsepower or large-tonnage refrigeration.
C. Any high-pressure steam is generated.
D. There is only one employee on shift.
Rationale: B. Grade 1 engineers are required for high-capacity plants (unlimited HP) to ensure
public safety in high-pressure environments.
7. Which type of pump is "Positive Displacement"?
A. Centrifugal pump.
B. Reciprocating pump.
C. Regenerative turbine pump.
Rationale: B. Reciprocating (piston) and gear pumps are positive displacement, meaning they
move a specific volume of fluid per stroke regardless of pressure.
8. "Saponification" in a boiler is caused by the reaction of high alkalinity with:
A. Scale.
B. Dissolved oxygen.
C. Fats and oils.
D. Nitrogen.
Rationale: C. When oil enters the boiler water, it reacts with alkaline chemicals to form soap,
leading to foaming and carryover.
9. A "Synchronous Motor" can be used to correct "Power Factor" by:
A. Increasing the voltage.
B. Over-exciting the DC field.
C. Reducing the frequency.
D. Running it in reverse.
, 2026 UPDATED QUESTIONS DOWNLOAD
Rationale: B. By over-exciting the field, the motor acts as a capacitor, which compensates for
the lagging power factor caused by induction motors in the plant.
10. What is the maximum "MAWP" allowed for a boiler constructed with "Lap-Seam"
longitudinal joints?
A. 15 psi.
B. 100 psi.
C. 150 psi.
D. 250 psi.
Rationale: A. Lap-seam boilers are considered dangerous at high pressures due to stress
concentrations; most jurisdictions (including MD) limit them to low pressure (15 psi) if they are
over 30 years old.
11. The "Latent Heat of Evaporation" for water at atmospheric pressure is:
A. 144 BTU.
B. 180 BTU.
C. 970.3 BTU.
D. 1150 BTU.
Rationale: C. It takes 970.3 BTUs to change 1 lb of water at 212°F to 1 lb of steam at 212°F.
12. In a refrigeration cycle, the "Expansion Valve" is located between the:
A. Compressor and Condenser.
B. Condenser and Evaporator.
C. Evaporator and Compressor.
D. Receiver and Compressor.
Rationale: B. The expansion valve (metering device) drops the pressure of the liquid
refrigerant before it enters the evaporator.
13. A "Closed Feedwater Heater" uses what to heat the water?
A. Direct mixing of steam and water.
B. Steam in a shell-and-tube heat exchanger.
C. Electricity.
D. Hot flue gases.
Rationale: B. In a closed heater, the steam and water do not mix; an "Open" heater (like a
Deaerator) mixes them directly.
14. What is the primary purpose of a "Steam Trap"?
A. To trap steam for later use.
B. To remove air and condensate without wasting steam.
C. To increase the pressure in the header.
D. To prevent water hammer in the boiler tubes.
Rationale: B. Traps are automatic valves that discharge condensate and air from steam lines
to maintain dry steam and prevent water hammer.
, 2026 UPDATED QUESTIONS DOWNLOAD
15. "Alkalinity" in boiler water is typically measured using:
A. A thermometer.
B. A titration test (pH or P/M alkalinity).
C. A hydrometer.
D. A pressure gauge.
Rationale: B. Proper alkalinity prevents corrosion but must be controlled to prevent foaming.
16. A "Surface Blowdown" is used to remove:
A. Sludge from the mud drum.
B. Dissolved solids and oils from the water's surface.
C. Air from the steam space.
D. Soot from the tubes.
Rationale: B. Surface blows control the "Total Dissolved Solids" (TDS) and prevent
foaming/priming.
17. If a safety valve on a high-pressure boiler is set at 150 psi, what is the minimum
required "Blowback"?
A. 1 psi.
B. 2 psi (or 2% of set pressure).
C. 10 psi.
D. 25 psi.
Rationale: B. Blowback is the difference between the popping pressure and the closing
pressure; ASME code specifies minimums to prevent "chattering" of the valve.
18. "Caustic Embrittlement" is a form of corrosion caused by:
A. High oxygen levels.
B. High concentrations of sodium hydroxide (caustic soda).
C. Low water level.
D. High steam velocity.
Rationale: B. This causes the metal to become brittle and crack, usually at seams or rivets.
19. A "Centrifugal Pump" should be started with the discharge valve:
A. Fully open.
B. Fully closed (to reduce starting load).
C. Halfway open.
D. Removed.
Rationale: B. Starting with the valve closed (or "throttled") reduces the starting torque/current
required by the motor.
20. What is the "Rupture Disk" on a low-pressure chiller (R-123) set to burst at?
A. 5 psi.
B. 15 psi.
C. 50 psi.
D. 150 psi.
