Stationary Engineer Practice Test Bank 2
With 600 Real Past Exam Questions and
Correct Answers/ Latest Stationary Engineer
License Exam Review 2026-2027
A blowdown valve is located at the lowest water space of a boiler for three
purposes - ANSWER-1. to remove precipitated sludge or loose scale \n2. To
permit rapid lowering of the boiler water if it has become too high accidentally \n3.
As a means of removing water from the boiler so that fresh water may be added to
keep the concentration of solids below the point where difficulties may be
experienced.
In the old power boiler which type of feed-water regulators were not used? -
ANSWER-Electronic
After opening a boiler for repairs how much oxygen is needed? - ANSWER-19%
What is the first thing you do when shutting down a boiler? - ANSWER-Turn off
(extinguish fire)
What is the legal limit of acceptable asbestos particles ? - ANSWER-0.1 fibers per
cubic centimeter
What is CREEP? - ANSWER-Creep is defined as the slow deformation of
material with time; with the deformation taking place at elevated temperatures with
no increase in stress.
What is the BTU content of Anthracite coal? - ANSWER-14000 btu/lb
1
,What substance transfers electrical current in a photocell? - ANSWER-Electricity
will flow when the CADMIUM is exposed to sufficient light.
What device acts as a check valve in both directions and keeps pumps primed? -
ANSWER-FOOT VALVES are used for pumps under suction pressure to prevent
backflow primed? on the suction line.
What protects boilers from explosion in the furnace? - ANSWER-A flame guard
system is an arrangement of flame detection system; interlocks; and relays which
will sense the presence of a proper flame in a furnace and cause fuel to be shut off
to the furnace if a hazardous condition develops (improper flame or combustion).
What size pipe is used as a header in a boiler operating at 100psi? - ANSWER-6
inches
What device is used to measure flue gasses - ANSWER-The Orsat Analyzer
Which low water cut off does not have a mercury switch? - ANSWER-The
Submerged electrode type
What is the btu output per lb of #4 fuel oil? - ANSWER-18
What substance is used for the electric transmission in an RTD? - ANSWER-
Platinum is used because of its stability at high temperatures
How much air is needed for the combustion of pulverized coal; gas; oil? -
ANSWER-50% for coal and 10-30% for gas & oil
2
,In old power boilers which type of feedwater regulators were not used? \n(A)
hydraulic \n(B) float \n(C) thermostatic expansion \n(D) electronic - ANSWER- D
electronic/electro-magnetic
What is hard forming scale? - ANSWER-Silica
With hydroxide present and normal oxygen levels which chemical will cause
problems? - ANSWER-Chlorine
The result from steel manufacturing and under pressure in boilers tends to cause
bulging? A bulge is caused by ? - ANSWER-A bulge is caused by overheating of
the shell plates and it affects the entire thickness of the plate.
A blister is caused by what ? - ANSWER-Slag inclusion forming a lamination at
the time the plate was rolled at the steel mill. A blister is a separation of the metal
from the shell plate caused by impurities rolled into the shell plate when formed.
With normal oxygen and low alkalinity. what is added to the boiler water? -
ANSWER-Neutralizing Amines
Which chemical is used to combat scale? - ANSWER-Combined phosphate
treatment- sodium phosphate
Other than sulfite what chemical is used to combat corrosion in boilers? -
ANSWER-Hydrazine
What will neutralize acid? - ANSWER-Alkali and Lime Soda
3
, What mechanical device is used to remove scale from firetubes? - ANSWER-A
tube rattler or vibrator
What percentage of the pressure should a boiler have before you test the lever of a
safety valve? - ANSWER-75%
Where is internal corrosion most likely to occur on a vertical tube boiler? -
ANSWER-Water leg-Mud leg
What are the minimum and maximum sizes permitted for blow down valves or
connections? - ANSWER-3/4"minimum 2 ½ " maximum
A boiler operating at a pressure of 65lbs. What is the smallest size feed and blow
off connections if the safety valve is set at 90 psi? - ANSWER-½ " feed ¾ " blow
off
How often should water columns and water glass levels be checked on a high
pressure boiler? - ANSWER-(Once A Shift)\nAt the beginning of each shift -
beginning of the work effort
What takes no actual action chemical part in combustion? - ANSWER-Nitrogen
How many ppm of EDTA are needed to tie up 1ppm of hardness? - ANSWER-
EDTA requires 10ppm of EDTA and 5 NTA to tie up each 1ppm hardness.
On a package boiler; how many ways could cause fire puffs when it is started up? -
ANSWER-6 ways 1-poor starting draft 2-incorrect firebox 3-wrong burner nozzle
4-lean fire 5- insufficient gas pilot or excessive gas pilot 6-water in the oil
4
With 600 Real Past Exam Questions and
Correct Answers/ Latest Stationary Engineer
License Exam Review 2026-2027
A blowdown valve is located at the lowest water space of a boiler for three
purposes - ANSWER-1. to remove precipitated sludge or loose scale \n2. To
permit rapid lowering of the boiler water if it has become too high accidentally \n3.
As a means of removing water from the boiler so that fresh water may be added to
keep the concentration of solids below the point where difficulties may be
experienced.
In the old power boiler which type of feed-water regulators were not used? -
ANSWER-Electronic
After opening a boiler for repairs how much oxygen is needed? - ANSWER-19%
What is the first thing you do when shutting down a boiler? - ANSWER-Turn off
(extinguish fire)
What is the legal limit of acceptable asbestos particles ? - ANSWER-0.1 fibers per
cubic centimeter
What is CREEP? - ANSWER-Creep is defined as the slow deformation of
material with time; with the deformation taking place at elevated temperatures with
no increase in stress.
What is the BTU content of Anthracite coal? - ANSWER-14000 btu/lb
1
,What substance transfers electrical current in a photocell? - ANSWER-Electricity
will flow when the CADMIUM is exposed to sufficient light.
What device acts as a check valve in both directions and keeps pumps primed? -
ANSWER-FOOT VALVES are used for pumps under suction pressure to prevent
backflow primed? on the suction line.
What protects boilers from explosion in the furnace? - ANSWER-A flame guard
system is an arrangement of flame detection system; interlocks; and relays which
will sense the presence of a proper flame in a furnace and cause fuel to be shut off
to the furnace if a hazardous condition develops (improper flame or combustion).
What size pipe is used as a header in a boiler operating at 100psi? - ANSWER-6
inches
What device is used to measure flue gasses - ANSWER-The Orsat Analyzer
Which low water cut off does not have a mercury switch? - ANSWER-The
Submerged electrode type
What is the btu output per lb of #4 fuel oil? - ANSWER-18
What substance is used for the electric transmission in an RTD? - ANSWER-
Platinum is used because of its stability at high temperatures
How much air is needed for the combustion of pulverized coal; gas; oil? -
ANSWER-50% for coal and 10-30% for gas & oil
2
,In old power boilers which type of feedwater regulators were not used? \n(A)
hydraulic \n(B) float \n(C) thermostatic expansion \n(D) electronic - ANSWER- D
electronic/electro-magnetic
What is hard forming scale? - ANSWER-Silica
With hydroxide present and normal oxygen levels which chemical will cause
problems? - ANSWER-Chlorine
The result from steel manufacturing and under pressure in boilers tends to cause
bulging? A bulge is caused by ? - ANSWER-A bulge is caused by overheating of
the shell plates and it affects the entire thickness of the plate.
A blister is caused by what ? - ANSWER-Slag inclusion forming a lamination at
the time the plate was rolled at the steel mill. A blister is a separation of the metal
from the shell plate caused by impurities rolled into the shell plate when formed.
With normal oxygen and low alkalinity. what is added to the boiler water? -
ANSWER-Neutralizing Amines
Which chemical is used to combat scale? - ANSWER-Combined phosphate
treatment- sodium phosphate
Other than sulfite what chemical is used to combat corrosion in boilers? -
ANSWER-Hydrazine
What will neutralize acid? - ANSWER-Alkali and Lime Soda
3
, What mechanical device is used to remove scale from firetubes? - ANSWER-A
tube rattler or vibrator
What percentage of the pressure should a boiler have before you test the lever of a
safety valve? - ANSWER-75%
Where is internal corrosion most likely to occur on a vertical tube boiler? -
ANSWER-Water leg-Mud leg
What are the minimum and maximum sizes permitted for blow down valves or
connections? - ANSWER-3/4"minimum 2 ½ " maximum
A boiler operating at a pressure of 65lbs. What is the smallest size feed and blow
off connections if the safety valve is set at 90 psi? - ANSWER-½ " feed ¾ " blow
off
How often should water columns and water glass levels be checked on a high
pressure boiler? - ANSWER-(Once A Shift)\nAt the beginning of each shift -
beginning of the work effort
What takes no actual action chemical part in combustion? - ANSWER-Nitrogen
How many ppm of EDTA are needed to tie up 1ppm of hardness? - ANSWER-
EDTA requires 10ppm of EDTA and 5 NTA to tie up each 1ppm hardness.
On a package boiler; how many ways could cause fire puffs when it is started up? -
ANSWER-6 ways 1-poor starting draft 2-incorrect firebox 3-wrong burner nozzle
4-lean fire 5- insufficient gas pilot or excessive gas pilot 6-water in the oil
4
