Maryland Grade 2 Stationary Engineer License Exam (2026
Edition) Questions with Answers & Rationales Newest |
Boiler Operations, Water Treatment & Safety | MD Stationary
Engineering Grade 2 Exam Prep
1. A Grade 2 engineer is overseeing a hot water heating boiler that has been operating with a
high dissolved oxygen level in the feedwater. During a routine inspection, the engineer notices
pinpoint pitting on the boiler shell near the waterline and a reddish-brown discoloration in the
water. Which condition is the MOST likely cause, and what is the BEST immediate action?
A. Oxygen pitting due to inadequate deaeration; increase the sulfite feed rate and verify the deaerator is
operating at the correct temperature and pressure.
B. Caustic embrittlement from high alkalinity; lower the boiler water alkalinity and add chelating agents.
C. Hydrogen damage from excessive acid cleaning; replace the boiler water and stop chemical treatment.
D. Galvanic corrosion from dissimilar metals; install sacrificial anodes and replace affected tubes.
Answer: A. Oxygen pitting due to inadequate deaeration; increase the sulfite feed rate and
verify the deaerator is operating at the correct temperature and pressure.
2. A stationary engineer is preparing to take a steam boiler off-line for an extended shutdown.
After securing the fuel supply and shutting down the burner, what is the CORRECT sequence
of actions to safely store the boiler (wet storage) and prevent oxygen pitting?
A. Drain the boiler completely, open all vents, and leave it dry with desiccant bags placed inside.
B. Fill the boiler to the top with treated feedwater, add an oxygen scavenger (sodium sulfite) to maintain a
residual, and close all valves to prevent air ingress.
C. Blow down the boiler to half-full, add a high concentration of phosphate, and leave the water in contact with
air.
D. Leave the boiler under normal operating pressure and temperature, maintain the burner on low fire, and
continue normal chemical treatment.
Answer: B. Fill the boiler to the top with treated feedwater, add an oxygen scavenger (sodium
sulfite) to maintain a residual, and close all valves to prevent air ingress.
3. During a shift, the low water cutoff on a firetube boiler fails to trip the burner, and the water
level continues to drop. The engineer observes the gauge glass showing no visible water. What
is the IMMEDIATE and CORRECT response?
A. Immediately shut off the burner, close the main steam stop valve, and allow the boiler to cool naturally
without adding water.
B. Immediately add feedwater to restore the water level, then investigate why the low water cutoff failed.
C. Increase the burner firing rate to raise the water level faster and maintain steam supply.
D. Blow down the boiler to remove sediment, then restart the burner on low fire.
Answer: A. Immediately shut off the burner, close the main steam stop valve, and allow the
boiler to cool naturally without adding water.
4. A steam boiler operates at 100 psig. The engineer needs to determine the saturation
temperature for proper operation. Using the steam tables, what is the approximate saturation
temperature, and which of the following is a critical safety consideration in this pressure
range?
A. Approximately 338°F; the boiler must be equipped with a safety relief valve set to relieve at or below the
, MAWP, and the gauge glass must be properly maintained.
B. Approximately 250°F; the boiler must be opened only when pressure is zero and the water is boiling.
C. Approximately 400°F; the boiler must have a fusible plug installed in the steam space.
D. Approximately 212°F; the engineer must wear full protective gear when operating valves.
Answer: A. Approximately 338°F; the boiler must be equipped with a safety relief valve set to
relieve at or below the MAWP, and the gauge glass must be properly maintained.
5. An engineer is troubleshooting a boiler that is producing black smoke and a low CO2 reading
in the flue gas. The fire is appearing as orange and smoky. What is the MOST likely cause and
the BEST adjustment to improve combustion?
A. Insufficient combustion air; increase the forced draft fan speed or open the air damper.
B. Excessive combustion air; reduce the forced draft fan speed or close the air damper.
C. High fuel oil temperature; decrease the fuel oil temperature to reduce atomization.
D. Low fuel pressure; increase the fuel pressure to raise the firing rate.
Answer: A. Insufficient combustion air; increase the forced draft fan speed or open the air
damper.
6. A water tube boiler is equipped with a continuous blowdown system. The engineer wants to
control the boiler water total dissolved solids (TDS) to prevent foaming and carryover. Which
parameter should be monitored, and what is the typical acceptable range for a
medium-pressure industrial boiler?
A. Conductivity; typical range is 2000-3500 micromhos/cm.
B. pH; typical range is 9.0-10.5.
C. Phosphate residual; typical range is 30-60 ppm.
D. Hardness; typical range is 0-5 ppm.
Answer: A. Conductivity; typical range is 2000-3500 micromhos/cm.
7. An engineer is performing a bottom blowdown on a boiler. According to the Maryland Grade
2 examination syllabus, what is the CORRECT procedure for bottom blowdown?
A. Open the quick-opening valve first, then the slow-opening valve; close the slow-opening valve first, then the
quick-opening valve.
B. Open the slow-opening valve first, then the quick-opening valve; close the quick-opening valve first, then
the slow-opening valve.
C. Open both valves fully simultaneously, hold for 10 seconds, and close both quickly.
D. Open the quick-opening valve fully, then throttle the slow-opening valve for 5 minutes, then close the
quick-opening valve.
Answer: A. Open the quick-opening valve first, then the slow-opening valve; close the
slow-opening valve first, then the quick-opening valve.
8. A feedwater system has a deaerator that is not venting properly, and the dissolved oxygen
(DO) level is increasing. Which of the following is a critical function of the deaerator vent, and
what would be the consequence of a blocked vent?
A. The vent discharges non-condensable gases (O2 and CO2) to the atmosphere; a blocked vent would
cause DO to rise and lead to boiler corrosion.
B. The vent allows excess condensate to escape; a blocked vent would cause water hammer in the deaerator.
C. The vent controls the steam pressure; a blocked vent would cause the deaerator to overpressure.
D. The vent provides make-up water; a blocked vent would starve the feedwater pump.
Answer: A. The vent discharges non-condensable gases (O2 and CO2) to the atmosphere; a
Edition) Questions with Answers & Rationales Newest |
Boiler Operations, Water Treatment & Safety | MD Stationary
Engineering Grade 2 Exam Prep
1. A Grade 2 engineer is overseeing a hot water heating boiler that has been operating with a
high dissolved oxygen level in the feedwater. During a routine inspection, the engineer notices
pinpoint pitting on the boiler shell near the waterline and a reddish-brown discoloration in the
water. Which condition is the MOST likely cause, and what is the BEST immediate action?
A. Oxygen pitting due to inadequate deaeration; increase the sulfite feed rate and verify the deaerator is
operating at the correct temperature and pressure.
B. Caustic embrittlement from high alkalinity; lower the boiler water alkalinity and add chelating agents.
C. Hydrogen damage from excessive acid cleaning; replace the boiler water and stop chemical treatment.
D. Galvanic corrosion from dissimilar metals; install sacrificial anodes and replace affected tubes.
Answer: A. Oxygen pitting due to inadequate deaeration; increase the sulfite feed rate and
verify the deaerator is operating at the correct temperature and pressure.
2. A stationary engineer is preparing to take a steam boiler off-line for an extended shutdown.
After securing the fuel supply and shutting down the burner, what is the CORRECT sequence
of actions to safely store the boiler (wet storage) and prevent oxygen pitting?
A. Drain the boiler completely, open all vents, and leave it dry with desiccant bags placed inside.
B. Fill the boiler to the top with treated feedwater, add an oxygen scavenger (sodium sulfite) to maintain a
residual, and close all valves to prevent air ingress.
C. Blow down the boiler to half-full, add a high concentration of phosphate, and leave the water in contact with
air.
D. Leave the boiler under normal operating pressure and temperature, maintain the burner on low fire, and
continue normal chemical treatment.
Answer: B. Fill the boiler to the top with treated feedwater, add an oxygen scavenger (sodium
sulfite) to maintain a residual, and close all valves to prevent air ingress.
3. During a shift, the low water cutoff on a firetube boiler fails to trip the burner, and the water
level continues to drop. The engineer observes the gauge glass showing no visible water. What
is the IMMEDIATE and CORRECT response?
A. Immediately shut off the burner, close the main steam stop valve, and allow the boiler to cool naturally
without adding water.
B. Immediately add feedwater to restore the water level, then investigate why the low water cutoff failed.
C. Increase the burner firing rate to raise the water level faster and maintain steam supply.
D. Blow down the boiler to remove sediment, then restart the burner on low fire.
Answer: A. Immediately shut off the burner, close the main steam stop valve, and allow the
boiler to cool naturally without adding water.
4. A steam boiler operates at 100 psig. The engineer needs to determine the saturation
temperature for proper operation. Using the steam tables, what is the approximate saturation
temperature, and which of the following is a critical safety consideration in this pressure
range?
A. Approximately 338°F; the boiler must be equipped with a safety relief valve set to relieve at or below the
, MAWP, and the gauge glass must be properly maintained.
B. Approximately 250°F; the boiler must be opened only when pressure is zero and the water is boiling.
C. Approximately 400°F; the boiler must have a fusible plug installed in the steam space.
D. Approximately 212°F; the engineer must wear full protective gear when operating valves.
Answer: A. Approximately 338°F; the boiler must be equipped with a safety relief valve set to
relieve at or below the MAWP, and the gauge glass must be properly maintained.
5. An engineer is troubleshooting a boiler that is producing black smoke and a low CO2 reading
in the flue gas. The fire is appearing as orange and smoky. What is the MOST likely cause and
the BEST adjustment to improve combustion?
A. Insufficient combustion air; increase the forced draft fan speed or open the air damper.
B. Excessive combustion air; reduce the forced draft fan speed or close the air damper.
C. High fuel oil temperature; decrease the fuel oil temperature to reduce atomization.
D. Low fuel pressure; increase the fuel pressure to raise the firing rate.
Answer: A. Insufficient combustion air; increase the forced draft fan speed or open the air
damper.
6. A water tube boiler is equipped with a continuous blowdown system. The engineer wants to
control the boiler water total dissolved solids (TDS) to prevent foaming and carryover. Which
parameter should be monitored, and what is the typical acceptable range for a
medium-pressure industrial boiler?
A. Conductivity; typical range is 2000-3500 micromhos/cm.
B. pH; typical range is 9.0-10.5.
C. Phosphate residual; typical range is 30-60 ppm.
D. Hardness; typical range is 0-5 ppm.
Answer: A. Conductivity; typical range is 2000-3500 micromhos/cm.
7. An engineer is performing a bottom blowdown on a boiler. According to the Maryland Grade
2 examination syllabus, what is the CORRECT procedure for bottom blowdown?
A. Open the quick-opening valve first, then the slow-opening valve; close the slow-opening valve first, then the
quick-opening valve.
B. Open the slow-opening valve first, then the quick-opening valve; close the quick-opening valve first, then
the slow-opening valve.
C. Open both valves fully simultaneously, hold for 10 seconds, and close both quickly.
D. Open the quick-opening valve fully, then throttle the slow-opening valve for 5 minutes, then close the
quick-opening valve.
Answer: A. Open the quick-opening valve first, then the slow-opening valve; close the
slow-opening valve first, then the quick-opening valve.
8. A feedwater system has a deaerator that is not venting properly, and the dissolved oxygen
(DO) level is increasing. Which of the following is a critical function of the deaerator vent, and
what would be the consequence of a blocked vent?
A. The vent discharges non-condensable gases (O2 and CO2) to the atmosphere; a blocked vent would
cause DO to rise and lead to boiler corrosion.
B. The vent allows excess condensate to escape; a blocked vent would cause water hammer in the deaerator.
C. The vent controls the steam pressure; a blocked vent would cause the deaerator to overpressure.
D. The vent provides make-up water; a blocked vent would starve the feedwater pump.
Answer: A. The vent discharges non-condensable gases (O2 and CO2) to the atmosphere; a
