Maryland Stationary Engineer Grade 2 Certification Exam 2026–2027 (150 Q&A Practice Test with Step-by Step Explanations | Boiler Room Operations, Feedwater Systems, Safety Devices & Efficiency Control)

Maryland Stationary Engineer Grade 2 Certification
Exam 2026–2027 (150 Q&A Practice Test with Step-by-
Step Explanations | Boiler Room Operations,
Feedwater Systems, Safety Devices & Efficiency
Control)


This practice set covers the core knowledge areas tested on the Maryland Grade 2 Stationary Engineer
exam.

Topics include boiler operation, combustion, water treatment, auxiliary equipment, controls, safety devices,
codes (ASME, NFPA), and Maryland regulations (COMAR).

Always verify current requirements with the Maryland Board of Stationary Engineers and PSI
Examination Services.




SECTION 1: BOILER OPERATION & COMBUSTION (Questions 1–20)
1. What is the maximum horsepower (HP) a Grade 2 stationary engineer is authorized to
operate in Maryland?

 A) 100 HP
 B) 299 HP
 C) 300 – 499 HP
 D) 500 HP or more

Explanation: A Grade 2 license authorizes operation of boilers and equipment in the range
of 300 to 499 horsepower. Grade 1 is required for 500 HP and above.

, 2. What is the minimum experience required to qualify for the Grade 2 examination via the
progressive pathway?

 A) 1 year as Grade 3
 B) 36 months as Grade 3
 C) 5 years as Grade 4
 D) 2 years as Grade 5

Explanation: The standard progressive pathway requires 36 months (3 years) of
documented experience as a Grade 3 stationary engineer.

3. During boiler startup, what is the proper order of operations?

 A) Ignite burner, open fuel valve, purge furnace
 B) Purge furnace, establish water level, ignite burner
 C) Open fuel valve, ignite burner, purge furnace
 D) Establish water level, ignite burner, purge furnace

Explanation: Proper startup requires: verify water level, perform pre-purge to remove
combustible gases, then initiate ignition sequence.

4. What is the purpose of a low-water fuel cutoff?

 A) Reduce fuel pressure
 B) Shut off fuel supply when water level drops below safe limits
 C) Increase feedwater flow
 D) Control steam pressure

Explanation: A low-water fuel cutoff is a critical safety device that interrupts the fuel supply
if water level falls to a dangerous point.

5. What is the function of a flame scanner in a burner management system?

 A) Measure fuel flow
 B) Detect presence or absence of flame
 C) Control combustion air
 D) Monitor stack temperature

Explanation: Flame scanners (ultraviolet or infrared) continuously monitor the flame and
will initiate a safety shutdown if flame is lost.

, 6. What is the recommended pH range for boiler water?

 A) 7.0 – 8.0
 B) 8.5 – 9.5
 C) 10.5 – 11.5
 D) 12.5 – 13.5

Explanation: Boiler water is maintained in the alkaline range (10.5–11.5) to prevent
corrosion and control scale formation.

7. What is the purpose of a safety valve on a boiler?

 A) Control steam temperature
 B) Relieve pressure if maximum allowable working pressure is exceeded
 C) Regulate fuel flow
 D) Monitor water chemistry

Explanation: The safety valve automatically opens at the set pressure to prevent
overpressure and potential explosion.

8. What is the function of an economizer?

 A) Superheat steam
 B) Preheat feedwater using flue gas heat
 C) Reduce emissions
 D) Control combustion air

Explanation: Economizers recover waste heat from flue gases to preheat feedwater,
improving overall boiler efficiency.

9. What is the purpose of a deaerator?

 A) Increase steam pressure
 B) Remove dissolved oxygen and non-condensable gases from feedwater
 C) Reduce fuel consumption
 D) Control steam temperature

Explanation: Deaerators use heat and mechanical agitation to remove oxygen and carbon
dioxide, preventing corrosion in the boiler and piping.

10. What is the most common cause of boiler furnace explosions?

,  A) High water level
 B) Improper purging before ignition
 C) Low steam pressure
 D) Excessive blowdown

Explanation: Accumulated unburned fuel in the furnace can ignite explosively. A proper
pre-purge cycle is essential to clear combustible gases.

11. What does a draft gauge measure?

 A) Steam pressure
 B) Pressure difference in the combustion chamber or flue
 C) Fuel flow rate
 D) Water level

Explanation: Draft gauges measure negative pressure (draft) in the furnace or flue,
ensuring proper combustion air flow.

12. What is the effect of scale buildup on boiler tubes?

 A) Improved heat transfer
 B) Reduced heat transfer and potential tube overheating
 C) Increased steam pressure
 D) Lower fuel consumption

Explanation: Scale acts as an insulator, reducing heat transfer efficiency and causing tube
metal temperatures to rise.

13. What is the purpose of a steam trap?

 A) Trap steam in the system
 B) Remove condensate and non-condensable gases while retaining steam
 C) Reduce steam pressure
 D) Increase steam temperature

Explanation: Steam traps automatically discharge condensate and air while preventing
steam loss, improving efficiency and preventing water hammer.

14. What is the function of a burner management system (BMS)?

 A) Adjust fuel viscosity