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100+ Free MN Boiler Operator Practice Questions

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2026 Statistics

Key Facts: MN Boiler Operator Exam

70%

Passing Score

MN DLI

$50

Exam Fee

MN DLI

2 hrs

Time Limit

MN DLI exam

6 Grades

License Levels

MN DLI

Minnesota requires a 70% passing score on a state-administered written exam. The $50 exam fee applies to all grades. Minnesota uses a multi-grade system: Chief, 1st, 2nd, 3rd, 4th, and 5th Class Engineer. Each grade has specific operating-hour requirements verified by affidavit. Higher grades authorize operation of larger and higher-pressure boiler systems. You must hold a lower grade before advancing.

About the MN Boiler Operator Exam

Minnesota's boiler engineer exam is administered by the Department of Labor and Industry. The state uses a grade-based licensing system with Chief Engineer and 1st through 5th Class Engineer levels. Candidates must submit an affidavit of operating experience and pay a $50 exam fee. The written exam covers boiler operations, safety systems, water treatment, combustion principles, and Minnesota-specific licensing regulations.

Questions

100 scored questions

Time Limit

2 hours

Passing Score

70%

Exam Fee

$50 (Minnesota Dept of Labor and Industry)

MN Boiler Operator Exam Content Outline

25%

Boiler Operations

Startup, shutdown, normal operation, and operating procedures for steam and hot-water boilers

25%

Safety & Emergency Procedures

Safety valves, low-water cutoffs, emergency shutdowns, and boiler room safety

20%

Maintenance & Inspections

Routine maintenance, boiler inspections, cleaning, and repair procedures

15%

Water Treatment & Combustion

Feedwater treatment, blowdown, water chemistry, fuel systems, and combustion control

15%

Minnesota Regulations & Licensing

DLI licensing, engineer grade system, experience affidavit requirements, and state boiler code

How to Pass the MN Boiler Operator Exam

What You Need to Know

  • Passing score: 70%
  • Exam length: 100 questions
  • Time limit: 2 hours
  • Exam fee: $50

Keys to Passing

  • Complete 500+ practice questions
  • Score 80%+ consistently before scheduling
  • Focus on highest-weighted sections
  • Use our AI tutor for tough concepts

MN Boiler Operator Study Tips from Top Performers

1Understand Minnesota's six-grade engineer system and the boiler size/pressure limits for each classification
2Study the affidavit of operating experience requirements — know exactly what documentation DLI expects
3Focus on safety valve sizing, testing frequency, and set-pressure calculations for different boiler types
4Master water treatment chemistry including hardness, alkalinity, dissolved oxygen, and blowdown calculations
5Review combustion principles including air-fuel ratios, draft systems, and flue gas analysis

Frequently Asked Questions

How much does the Minnesota boiler engineer exam cost?

The Minnesota boiler engineer exam costs $50 per attempt. This fee applies to all engineer grade levels — from 5th Class through Chief Engineer. The fee is payable to the Department of Labor and Industry when you schedule your exam.

What are the Minnesota boiler engineer grade levels?

Minnesota uses six grade levels: 5th Class (lowest), 4th Class, 3rd Class, 2nd Class, 1st Class, and Chief Engineer (highest). Each grade authorizes operation of progressively larger and higher-pressure boiler systems. You must meet specific operating-hour requirements and pass a written exam for each grade.

What experience documentation does Minnesota require?

Minnesota requires an affidavit of operating experience signed by your supervising licensed engineer. The affidavit must verify the hours you worked, the types of boilers operated, and the pressure ratings involved. Specific hour requirements vary by grade level.

Can I skip grade levels in Minnesota?

No. Minnesota requires you to hold each lower grade before advancing. You must start at 5th Class and work your way up, meeting the experience-hour requirements and passing the written exam at each grade level.