✓ TradeExamPro

TradeExamPro › Cranes & Equipment

Boiler Operator & Stationary Engineer Practice Test

Boiler types and fittings, combustion, feedwater and water treatment, steam systems, operation, safety devices and emergencies for low and high pressure boiler licences.

200 questions · 7 topics · free, no sign-up

Mixed practice test

10 questions, graded as you go, with the reason for every answer. No sign-up.

Timed mock exam

50 questions in 60 minutes, drawn from every topic. No answers shown until the end, then a score, your weakest topics and a review of what you missed.

Practise by topic

Sample questions

A hot-water heating boiler is classed as low pressure when it does not exceed which limits?

  1. 160 psi and 212°F
  2. 125 psi and 250°F
  3. 30 psi and 250°F
  4. 160 psi and 250°F
Show the answer

D. 160 psi and 250°F

The heating boiler rules cover hot-water boilers up to 160 psi and 250°F. 212°F is only the boiling point at atmospheric pressure; water under pressure can be hotter and still be within the low-pressure class.

Reference: ASME BPVC Section IV, scope (160 psi, 250°F water)

What is the effect of running a burner with far more excess air than it needs?

  1. More heat is carried up the stack
  2. More soot forms in the tubes
  3. The flame becomes long and smoky
  4. The fuel flow rises to compensate
Show the answer

A. More heat is carried up the stack

Air that takes no part in combustion is heated in the furnace and carries that heat out of the stack, so efficiency drops. Soot and a smoky flame are signs of too little air, the opposite fault.

Reference: Combustion: excess air and stack loss

Why is it worthwhile to return as much condensate as possible to the boiler?

  1. It is cold and dense, so it pumps more easily
  2. It is hot and pure, saving fuel and treatment
  3. It is high in oxygen, which protects the tubes
  4. It is high in hardness, which coats the shell
Show the answer

B. It is hot and pure, saving fuel and treatment

Condensate is nearly distilled water that still holds a good deal of heat, so reusing it cuts fuel, makeup water and chemical use. It is not cold; it normally returns well above the makeup water temperature.

Reference: Feedwater systems: condensate return

How does a safety valve on a steam boiler differ from a relief valve on a liquid system?

  1. It opens slowly as pressure rises
  2. It pops fully open at its set pressure
  3. It is opened by an electric solenoid coil
  4. It closes only when reset by hand
Show the answer

B. It pops fully open at its set pressure

A steam safety valve has a huddling chamber that makes it pop wide open at the set pressure and stay open until pressure falls. Opening gradually in proportion to overpressure is how a liquid relief valve behaves.

Reference: Boiler fittings: safety valves and relief valves

A boiler is rated at 150 boiler horsepower. What is its rated heat output in Btu per hour? (1 BHP = 33,475 Btu/hr)

Answer in Btu/hr.

Show the answer

5021250 Btu/hr

Output = BHP × 33,475 = 150 × 33,475 = 5,021,250 Btu/hr.

Reference: Boiler horsepower: 33,475 Btu/hr

Exams this helps with

ExamWho runs itWhere
Boiler operator / fireman (low and high pressure) readyState and city boardsUnited States (varies by state)
Stationary / power engineer (classes 1 to 4) readyState and city boards, NIULPEUnited States (varies by state)

Tell us what to improve · More cranes & equipment practice