STATIONARY ENGINEER COMPREHENSIVE EXAM
QUESTIONS AND SOLUTIONS 2025/2026 GRADED A+
✔✔Hide out in a boiler causes what to precipitate? - ✔✔Sodium Phosphate
✔✔What is the main cause of generating tubes to failing? - ✔✔Overheating at the lower
tubes due to scale; sludge and poor circulation.
✔✔A boiler water having high Alkalinity could develop - ✔✔Caustic Embrittlement
✔✔What does condensate polishing used for? - ✔✔To clean & purify returned
condensate
✔✔Acid cleaning removes what? - ✔✔Metallic Oxide
✔✔Chelants controls what in a boiler systems? - ✔✔Metal Oxide Deposits
✔✔To prevent condensate corrosion in the return lines you should add what? -
✔✔Amine Morpholine & Cyclohexylamine
✔✔What do you do when Laying a boiler up wet? - ✔✔If there is no deaerated water
heater you should heat the water up for 8 hours with the vent open and add Sulfite &
caustic soda.
✔✔When doing a Dry Lay up what do you put in it - ✔✔Quick lime & Silica gel
✔✔This is a not a Fluorocarbon? - ✔✔Ammonia
✔✔What refrigerant is flammable & Non Toxic? - ✔✔Propane
✔✔Recycled & filtered refrigerant can be used where? - ✔✔Same type & Same Owner
✔✔What Refrigerant Classification is Ammonia R-717? - ✔✔B2
✔✔How is moisture taken out of refrigerant system? - ✔✔Filter Drier ; high vaccum
✔✔What is the max toxicity level of class B refrigerant? - ✔✔400ppm
✔✔On Gas fired Boilers what isthe proper Gas to Air mixture? - ✔✔30% to 70% and
can be 100% in special arrangements
✔✔What is the Equalizing system? - ✔✔Equalizing system is for warming up steam
lead
,✔✔Which is not an organic sludge conditioner? - ✔✔Amines
✔✔Which byproduct has the highest heating valve? - ✔✔Butane
✔✔An increase of 10 to 20 degrees above design temp can reduce creep life by how
many years? - ✔✔10 to 20 (pg578-579)
✔✔What is ultrasound testing? - ✔✔A nondestructive test for metal thickness in boilers.
(pg 243; 610)
✔✔What are the causes of gas turbine blade failure? - ✔✔Deposit accumulation;
erosion; corrosion
✔✔What is the speed of steam through a pipe? - ✔✔10 000 ft/sec at pressures above
16 psi 5 000 ft/sec at pressures below 16 psi
✔✔On an open air evaporator what is the most likely to occur? - ✔✔Bacteria and algae
build up
✔✔What pressure controls are on a steam boiler? - ✔✔Operator pressure cut out and
upper limit control
✔✔What are the temperature controls on a hot water boiler? - ✔✔Operating limit control
and upper limit control
✔✔On a single boiler high pressure boiler what type of valves are needed - ✔✔Single
supply OS& Y
✔✔What is the last device to prevent boiler from overheating - ✔✔Flame guard system
✔✔Carbon dioxide is what type of refrigerant? - ✔✔B2
✔✔Hot water boilers have how many manual resets on LWCO. - ✔✔1
✔✔Steam boilers have how many manual resets on LWCO - ✔✔2
✔✔Class 3 is how flammable? - ✔✔Hazards
✔✔Hardness formula - ✔✔(Calcium X 2.5)+ (Magnesium X 4.1)
✔✔Lack of penetration in a weld joint is most accuratley detected by the use
of__________________ testing. - ✔✔Radiographic - X-ray
, ✔✔The test most commonly used to determine the wall thickness of pipe and flat plate
is________. - ✔✔Ultrasonic
✔✔Firetube boilers are likely to leak due to cracking; burning and corrosion of the
_________ _______. - ✔✔tube ends
✔✔The ratio of a boiler's heat output to it's heat input is_____________________. -
✔✔boiler efficinncy
✔✔Welding flat strips of metal between the waterwall tubes is known as ________ wall
construction. - ✔✔membrane
✔✔The general classification of superheaters includes _________ and _________
types. - ✔✔Radient and Convection
✔✔Pipes connecting the water column to the boiler must be a minimum diameter of
_____" - ✔✔1"
✔✔Cogeneration plants sell ____ to local industrial plants and______ to the local utility.
- ✔✔Steam ; Electricity
✔✔Saftey Valve capacity must be sufficient to relieve all the steam that the boiler can
generate at the _____ _____ ______ without allowing the pressure to rise more than
_% above the MAWP. - ✔✔Max firing rate ; 6%
✔✔The______ _______ mechanism on the High Limit Control calls attention if the
_________ control has malfunctioned. - ✔✔Manual reset ; Operating control
✔✔A slow opening blowdown valve must complete _______ turns between full open
and full shut. - ✔✔5
✔✔Perminatly hard water is water that contains large quantities of calcium and
magnesium ________ - ✔✔Sulfates
✔✔_________ is used on high pressure steam plants to absorb oxygen. It is not
typically used on low pressure plants because it is a slow reaction to absorb oxygen. -
✔✔Hydrazine
✔✔________ usually causes cavities to form at grain boundaries and these cavities
coalesce to form a crack. - ✔✔CREEP
QUESTIONS AND SOLUTIONS 2025/2026 GRADED A+
✔✔Hide out in a boiler causes what to precipitate? - ✔✔Sodium Phosphate
✔✔What is the main cause of generating tubes to failing? - ✔✔Overheating at the lower
tubes due to scale; sludge and poor circulation.
✔✔A boiler water having high Alkalinity could develop - ✔✔Caustic Embrittlement
✔✔What does condensate polishing used for? - ✔✔To clean & purify returned
condensate
✔✔Acid cleaning removes what? - ✔✔Metallic Oxide
✔✔Chelants controls what in a boiler systems? - ✔✔Metal Oxide Deposits
✔✔To prevent condensate corrosion in the return lines you should add what? -
✔✔Amine Morpholine & Cyclohexylamine
✔✔What do you do when Laying a boiler up wet? - ✔✔If there is no deaerated water
heater you should heat the water up for 8 hours with the vent open and add Sulfite &
caustic soda.
✔✔When doing a Dry Lay up what do you put in it - ✔✔Quick lime & Silica gel
✔✔This is a not a Fluorocarbon? - ✔✔Ammonia
✔✔What refrigerant is flammable & Non Toxic? - ✔✔Propane
✔✔Recycled & filtered refrigerant can be used where? - ✔✔Same type & Same Owner
✔✔What Refrigerant Classification is Ammonia R-717? - ✔✔B2
✔✔How is moisture taken out of refrigerant system? - ✔✔Filter Drier ; high vaccum
✔✔What is the max toxicity level of class B refrigerant? - ✔✔400ppm
✔✔On Gas fired Boilers what isthe proper Gas to Air mixture? - ✔✔30% to 70% and
can be 100% in special arrangements
✔✔What is the Equalizing system? - ✔✔Equalizing system is for warming up steam
lead
,✔✔Which is not an organic sludge conditioner? - ✔✔Amines
✔✔Which byproduct has the highest heating valve? - ✔✔Butane
✔✔An increase of 10 to 20 degrees above design temp can reduce creep life by how
many years? - ✔✔10 to 20 (pg578-579)
✔✔What is ultrasound testing? - ✔✔A nondestructive test for metal thickness in boilers.
(pg 243; 610)
✔✔What are the causes of gas turbine blade failure? - ✔✔Deposit accumulation;
erosion; corrosion
✔✔What is the speed of steam through a pipe? - ✔✔10 000 ft/sec at pressures above
16 psi 5 000 ft/sec at pressures below 16 psi
✔✔On an open air evaporator what is the most likely to occur? - ✔✔Bacteria and algae
build up
✔✔What pressure controls are on a steam boiler? - ✔✔Operator pressure cut out and
upper limit control
✔✔What are the temperature controls on a hot water boiler? - ✔✔Operating limit control
and upper limit control
✔✔On a single boiler high pressure boiler what type of valves are needed - ✔✔Single
supply OS& Y
✔✔What is the last device to prevent boiler from overheating - ✔✔Flame guard system
✔✔Carbon dioxide is what type of refrigerant? - ✔✔B2
✔✔Hot water boilers have how many manual resets on LWCO. - ✔✔1
✔✔Steam boilers have how many manual resets on LWCO - ✔✔2
✔✔Class 3 is how flammable? - ✔✔Hazards
✔✔Hardness formula - ✔✔(Calcium X 2.5)+ (Magnesium X 4.1)
✔✔Lack of penetration in a weld joint is most accuratley detected by the use
of__________________ testing. - ✔✔Radiographic - X-ray
, ✔✔The test most commonly used to determine the wall thickness of pipe and flat plate
is________. - ✔✔Ultrasonic
✔✔Firetube boilers are likely to leak due to cracking; burning and corrosion of the
_________ _______. - ✔✔tube ends
✔✔The ratio of a boiler's heat output to it's heat input is_____________________. -
✔✔boiler efficinncy
✔✔Welding flat strips of metal between the waterwall tubes is known as ________ wall
construction. - ✔✔membrane
✔✔The general classification of superheaters includes _________ and _________
types. - ✔✔Radient and Convection
✔✔Pipes connecting the water column to the boiler must be a minimum diameter of
_____" - ✔✔1"
✔✔Cogeneration plants sell ____ to local industrial plants and______ to the local utility.
- ✔✔Steam ; Electricity
✔✔Saftey Valve capacity must be sufficient to relieve all the steam that the boiler can
generate at the _____ _____ ______ without allowing the pressure to rise more than
_% above the MAWP. - ✔✔Max firing rate ; 6%
✔✔The______ _______ mechanism on the High Limit Control calls attention if the
_________ control has malfunctioned. - ✔✔Manual reset ; Operating control
✔✔A slow opening blowdown valve must complete _______ turns between full open
and full shut. - ✔✔5
✔✔Perminatly hard water is water that contains large quantities of calcium and
magnesium ________ - ✔✔Sulfates
✔✔_________ is used on high pressure steam plants to absorb oxygen. It is not
typically used on low pressure plants because it is a slow reaction to absorb oxygen. -
✔✔Hydrazine
✔✔________ usually causes cavities to form at grain boundaries and these cavities
coalesce to form a crack. - ✔✔CREEP
