Free MD Boiler Operator Exam Flashcards

The Board of Stationary Engineers, inside the Maryland Department of Labor. The statute is Business Occupations and Professions Article, Title 6.5; the Board's own regulations are COMAR Title 09, Subtitle 17. The equipment itself is regulated separately under the Boiler and Pressure Vessel Safety Act (Public Safety Article, Title 12, Subtitle 9) and COMAR 09.12.01, the Board of Boiler Rules, enforced by the Chief Boiler Inspector. Exam questions often test which body of law answers which question.

Overseeing a power plant, plant of machinery, or boiler that generates pressure of more than 15 psi AND operates at 30 or more horsepower. Both thresholds must be met. The Board's notice to owners describes 30 HP as about 1,003,000 Btu/hr, or 1,034 lb/hr of steam.

A steam boiler operating at 15 psig or less, or a hot water boiler at 160 psig or less and 250 F or less. Overseeing a heating boiler is expressly excluded from providing stationary engineer services, so that unit alone does not require a licensed operator even though it still falls under boiler inspection law.

Grade 3, for 100 to 299 horsepower. Maryland sets the grade from the horsepower and operating pressure of the largest single piece of regulated equipment, never the combined plant total, so three 200 HP boilers do not add up to a 600 HP Grade 1 plant.

Yes, if the equipment meets the pressure and horsepower thresholds. Nothing in Title 6.5 exempts refrigeration or diesel prime movers. The Act's scope reaches turbines, generators, chiller plants, compressors, pumps, motors, switchgear, fuel systems and other equipment that can create a hazard if mishandled.

It is a misdemeanor: up to a $1,000 fine or six months in jail, and on a second or subsequent conviction up to $5,000 or two years. The Board may also impose a civil penalty of up to $5,000 per violation. The prohibition reaches the employer too, since a person may not allow an individual to work unlicensed or above their grade.

Grade 5 covers 30 to 99 HP in a building not open for public use. Grade 4 covers 30 to 99 HP in any building regardless of use. Grade 3 covers 100 to 299 HP, Grade 2 covers 300 to 499 HP, and Grade 1 covers 500 HP or more.

Ohm's law: volts = amps x ohms (E = I x R). Power in watts = volts x amps (P = E x I), which also equals I squared x R. Example: a 24 V circuit through a 6 ohm relay coil draws 4 A and dissipates 96 W. In a series circuit the same current flows through every part and the voltage drops add up; in a parallel circuit every branch sees the same voltage and the branch currents add up.

A Grade 5 licensee must visit at least once every 24 hours the boiler is in operation. Grades 4, 3, 2 and 1 must have a licensee of that grade in attendance at all times the boiler is operating; the only exception is the Grade 4 school rule in Section 6.5-302(b)(3). Without a monitoring system and automatic controls there is no reduced schedule for Grades 3, 2 or 1.

The licensee must be responsible for safe operation of the equipment at all times, must be available to observe the monitoring equipment and make necessary adjustments at least once every 24 hours, and must maintain a daily inspection log. Fail any one and the full attendance requirement returns.

Grade 5 visits at least once per week. In a hospital, hotel, residential facility or other building generally open to the public, Grades 4 through 1 must visit at least once every 8 hours the building is open for public use; for a Grade 4 boiler in a school the 8-hour visits apply during regular school hours and, outside them, only while at least 150 people occupy the building. A Grade 3, 2 or 1 boiler that is not in a public building needs no regular scheduled visitation.

The Grade 4 licensee must be in attendance at all times during regular school hours, and outside regular school hours only when at least 150 students, faculty or members of the public occupy the building where the boiler is located. Occupancy, not the clock alone, drives the staffing.

Warm it up slowly and vent the air, then raise its pressure until it is just below header pressure before slowly cracking the stop valve; the boiler's non-return valve opens only once boiler pressure exceeds the header. Cutting in a cold or low-pressure boiler lets header steam flow backward into it, and the condensate that forms causes water hammer that can wreck the valve or piping. Watch the water level closely through the swell that follows.

It depends on the grade. The PSI bulletin (updated September 1, 2024) makes the Grade 5 and Grade 4 examinations open book, limited to the listed references such as the Boiler Operator's Guide and Lessons in Electric Circuits: no study guides, no handwritten notes, and only approved permanent tabs. The Grade 3, 2 and 1 examinations are closed book. The Board warns that the listed references supplied the subject matter for the questions, so study from them.

A candidate who fails or fails to appear must file a new application and pay a new application fee; the examination fee is nonrefundable. Using unauthorized material during the exam is far worse: the application is rejected immediately and the applicant is barred from reexamination for at least one year.

The Board's licensing FAQ requires a 30-day wait to reapply after a failure, and 60 days for any subsequent request, with the exam fee paid each time. A passing result is not permanent either: COMAR 09.17.01.02 requires you to apply for licensure and pay all applicable fees within two years of passing or the result lapses.

The license expires every other year on the anniversary of its issue date and renews for another two-year term (Section 6.5-312). Within two years of expiration the Board must reinstate it on payment of the past-due renewal fees and a reinstatement fee (Section 6.5-313). The Board's FAQ states that a license expired more than 24 consecutive months cannot be renewed and the holder must sit the examination again.

No. The Board states it holds no reciprocal agreement with any state or jurisdiction, so an out-of-state licensee still takes the Maryland exam. Section 6.5-307 permits an examination waiver only if the other state waives its exam for Maryland licensees to a similar extent. Section 6.5-306.1 separately lets the Board approve a candidate for a grade exam based on years of lawful Maryland service.

Stack flue gas temperature, burner on and off status, and flame safety control normal and flame-failure status, plus steam pressure and water level on a steam boiler, or temperature on a hot water boiler of 30 to 299 HP. At 300 HP or more the system must also RECORD those points, and a hot water boiler must cover pressure as well as temperature.

The alarm must activate on high stack flue gas temperature, burner off, flame failure, and abnormal steam pressure or water level, or on a hot water boiler abnormal temperature (plus pressure and level at 300 HP or more). Automatic burner shutdown has a shorter list: high stack flue gas temperature; high steam pressure or low or high water level on a steam boiler; high water temperature on a hot water boiler (plus high pressure or low level at 300 HP or more). Burner off, flame failure and low steam pressure alarm but do not by themselves trigger the shutdown rule.

Turbine exhaust steam condenses on the outside of tubes cooled by circulating water, which creates a vacuum at the turbine exhaust and greatly increases the usable energy drop across the turbine; the condensate is recovered as high-purity feedwater. Air in-leakage, fouled tubes, warm or insufficient circulating water, or a failed air ejector raises the exhaust back-pressure, cuts turbine output and can trip the unit. The cooling tower rejects the heat the condenser picks up.

Manual reset means the licensee or the licensee's designee must physically inspect the boiler and its appurtenances before restart. Resetting from a screen is not enough. The licensee remains responsible for safe operation at all times under Section 6.5-302, and the Board may accept an alternate monitoring system only if it gives comparable safety.

Trip the burner and secure the fuel first, then isolate the boiler from the header by closing its stop valve. Keep the feedwater on as long as the pump can hold a level, because water keeps the remaining tubes cool; this is the opposite of a dry low-water emergency, where you never add water. Let the boiler cool and depressurize before anyone opens it, and log the event for the inspector.

A power boiler or a high pressure, high temperature water boiler gets a certificate inspection annually, plus an annual external inspection while under pressure where possible. Other boilers and pressure vessels are inspected biennially, except amusement attraction objects, which are annual.

Only with internal continuous water treatment under the general supervision of a professional engineer experienced in boiler water treatment, and records available to the inspector showing the date, time and reason the boiler is out of service plus chemical and physical analyses of boiler water sampled at intervals of no more than 48 hours of operation.

The owner or user must post the inspection certificate under glass in the room containing the object (or in a convenient accessible place if it is not in a building) and must notify the Chief Boiler Inspector within 24 hours after an accident or explosion, by email and telephone under COMAR 09.12.01.28, without disturbing the wreckage except to save life. The person performing an installation must give the Commissioner notice at least 30 days before installing a boiler or pressure vessel. The certificate also states the maximum pressure allowed.

In a firetube boiler the hot gases pass inside tubes surrounded by water, giving a large water volume that responds slowly but stores a lot of energy. In a watertube boiler the water is inside the tubes and gases pass outside, so it raises steam quickly, handles high pressure and swinging loads, and holds less water.

A power boiler generates steam or other vapor above 15 psig and is built to ASME Section I. A heating boiler stays at or below 15 psig steam, or 160 psig and 250 F for hot water, and is built to ASME Section IV. Pressure vessels fall under Section VIII. Maryland uses the same dividing line for licensing and for inspection intervals.

The heat required to evaporate 34.5 pounds of water per hour from and at 212 F, about 33,475 Btu/hr. It is an output rating, not the burner's fuel input, so a boiler's horsepower rating is not the same number as its input rating and the two should never be swapped when deciding the license grade.

Maximum allowable working pressure, the highest pressure at which the object may be operated. It is stamped on the nameplate and appears on the inspection certificate, and it caps the safety valve set pressure. For a code-stamped object Maryland determines the maximum allowable pressure from the ASME code edition under which it was built and stamped.

The water column dampens surging so the gauge glass shows a readable level, and it carries the level controls and try cocks. Blowing down the column and the glass proves the connections are clear. A level that never moves usually means a plugged connection giving a false reading, not a perfectly steady boiler.

It is the last line of defense and works on pressure alone, with no power or logic behind it. It must be connected directly to the boiler with no shutoff valve in between, must be set no higher than the MAWP, and must discharge to a safe location with a drain so condensate cannot collect on the disc.

Lifting the valve manually at operating pressure proves the valve is free and not stuck by scale or corrosion. It does not prove the set pressure; only a pressure test does that. Never gag, weight or readjust a valve to stop it from lifting, because a lifting valve means an operating or limit control has already failed.

It shuts off the fuel when the water falls to a preset level, protecting against a dry-fire that can overheat and rupture the pressure parts. Blow it down on schedule to clear sediment from the float chamber and confirm the burner actually stops. If the burner keeps firing during the test, take the boiler off line.

Secure the fuel at once and do NOT add feedwater to a boiler that has lost its water level. Cold water striking overheated metal can flash to steam and cause a violent failure. Let the boiler cool naturally, then have the pressure parts inspected before returning it to service.

It sequences the whole light-off. It forces a pre-purge to sweep unburned fuel from the furnace before ignition, proves the pilot, proves main flame, and closes the fuel valve within the programmed flame failure response time if the scanner loses sight of flame. Jumpering a scanner or an interlock removes the only protection against a furnace explosion.

The operating control cycles or modulates the burner to hold normal pressure or temperature in everyday service. The high limit is a separate safety control that shuts the burner down only when the operating control has failed, and it is usually manual reset so someone must come to the boiler and investigate before it can fire again.

Enough oxygen delivered with sufficient temperature, turbulence and time. Complete combustion of a hydrocarbon fuel yields mainly carbon dioxide and water vapor. Carbon monoxide, smoke, soot or unburned fuel odor mean combustion is incomplete, which wastes fuel and creates an explosion and poisoning hazard.

A little air above the theoretical amount ensures every fuel particle finds oxygen. Too little gives carbon monoxide, soot and unburned fuel. Too much carries usable heat out the stack and lowers efficiency. Tune by flue gas analysis of oxygen and carbon dioxide with carbon monoxide, not by flame appearance alone.

Natural draft relies on stack effect alone. Forced draft uses a fan to push air in and puts the furnace under positive pressure. Induced draft uses a fan to pull gases out and holds it negative. Balanced draft uses both fans and keeps the furnace slightly negative so flue gas does not leak into the boiler room.

A purge sweeps out any accumulated fuel vapor before an ignition source appears, which is the single defense against a furnace explosion. Pre-purge clears the furnace before ignition; post-purge clears it after shutdown. Shortening or bypassing a purge to restore steam faster is one of the most dangerous shortcuts in a boiler room.

Hardness, mainly calcium and magnesium, bakes into hard scale on heating surfaces and insulates them, raising metal and stack temperatures. Sludge is loose suspended solids that settle low in the drum. Scale is fought by prevention through softening and internal treatment; sludge is removed by bottom blowdown.

Bottom blowdown is short and intermittent, taken from the lowest point to expel settled sludge. Continuous surface blowdown skims just below the water line where dissolved solids concentrate, holding total dissolved solids in range. They remove different contaminants from different places, so one never substitutes for the other.

Oxygen causes pitting, a localized attack that perforates a tube while overall metal loss stays small. A deaerator removes most of it mechanically by heating the feedwater and venting the released gases; an oxygen scavenger chemical then removes the residual. The mechanical and chemical steps work together, not in place of each other.

Boiler water carried into the steam by priming or foaming, contaminating steam lines and causing water hammer and damage to turbines and traps. The usual causes are high dissolved solids, oil or grease contamination, carrying the water level too high, and sudden load swings. The first responses are a level check and blowdown.

It exchanges calcium and magnesium for sodium so hardness cannot form scale, and it is regenerated with brine. It does not remove dissolved oxygen, dissolved solids, or alkalinity, so a softener never replaces deaeration, blowdown or internal chemical treatment.

To supply enough net positive suction head. The feed pump handles water near its boiling point, so if suction pressure falls to the vapor pressure the water flashes to steam in the impeller eye. That is cavitation: it sounds like pumping gravel, erodes the impeller, and destroys the pump if the operator ignores it.

A centrifugal pump's flow falls as discharge pressure rises and it can tolerate a briefly closed discharge. A positive displacement pump moves a fixed volume every stroke or revolution, so running it against a closed discharge without a relief valve will burst piping or break the pump.

The compressor raises refrigerant pressure and temperature, the condenser rejects heat and liquefies the refrigerant, the expansion device drops the pressure, and the evaporator absorbs heat from the load. Maryland treats large refrigeration compressors as regulated equipment, so a plant with chillers but no boiler can still need a licensed engineer.

It protects the motor windings from sustained current above the nameplate full-load amps, which is a heat problem rather than a short circuit. Repeated tripping signals an overloaded, misaligned or failing driven machine. Oversizing the overload to stop the nuisance trips removes the protection and burns the motor. Lock out the disconnect before working on any driven equipment.