Dc 3rd Class Test, 3rd Class Stationary Steam Engineer License Prep,
Stationary Engineer, Station Engineer Exam, Dc 1st Class Boiler
Study Guide Exam Prep
DC 3RD CLASS TEST, 3RD CLASS STATIONARY STEAM ENGINEER
LICENSE PREP, STATIONARY ENGINEER, STATION ENGINEER EXAM, DC
1ST CLASS BOILER STUDY GUIDE EXAM PREP NEWEST 2026/2027
ACTUAL EXAM COMPLETE QUESTIONS AND CORRECT DETAILED
ANSWERS (VERIFIED ANSWERS) |ALREADY GRADED A+||BRAND NEW
VERSION!!
What is the first thing to do when shutting down a boiler? - Correct
Answer-To turn off the fire
A flow control should be blown down when? - Correct Answer-once per
shift
How often should you check the Low Water Fuel Cut off? - Correct
Answer-once per shift
Why is oil added to the refrigerant? - Correct Answer-lubrication of the
compressor
Keep refrigerant migrating
1|Page
, Dc 3rd Class Test, 3rd Class Stationary Steam Engineer License Prep,
Stationary Engineer, Station Engineer Exam, Dc 1st Class Boiler
Study Guide Exam Prep
Recycled and filtered refrigerant can be used where? - Correct Answer-
By the same owner in the same type of equipment
Data printed on the equipment nameplate would include manufacturer,
model, and serial number and________________? - Correct Answer-
Stamp of approval from commissioning authority
How many BTU's does it take to raise 10 lbs of steam from 40 to 41
degrees? - Correct Answer-1 BTU
When working on a boiler, permits should be required? - Correct
Answer-For every shift
How many things do safety controls protect against? - Correct Answer-
Over pressure
Over Heating
Fire side explosions
What chemical compounds in water cause permanent hardness? -
Correct Answer-Calcium Sulfate and Magnesium Silicate
2|Page
, Dc 3rd Class Test, 3rd Class Stationary Steam Engineer License Prep,
Stationary Engineer, Station Engineer Exam, Dc 1st Class Boiler
Study Guide Exam Prep
What chemicals are used to combat corrosion? - Correct Answer-
sodium sulfite and hydrazine
You have boiler water that is found to have a PH of 5. What compound
do you add to neutralize? - Correct Answer-bases
What produces soft scale? - Correct Answer-calcium carbonate and
magnesium carbonate
With normal oxygen and low alkalinity, what is added to boiler water? -
Correct Answer-Neutralizing Amines
What is hard forming scale? - Correct Answer-silica
Which chemicals are used to combat scale? - Correct Answer-Combined
Phosphate Treatment
Which compound is not heat produce? - Correct Answer-Nitrogen
What takes no actual action in combustion? - Correct Answer-Nitrogen
3|Page
, Dc 3rd Class Test, 3rd Class Stationary Steam Engineer License Prep,
Stationary Engineer, Station Engineer Exam, Dc 1st Class Boiler
Study Guide Exam Prep
With hydroxide present & normal oxygen levels; which chemical will
cause problems? - Correct Answer-Chlorine
What mechanical device is used to remove scale from Fire Tubes? -
Correct Answer-A Tube Rattler or Vibrator is used
Who can make Adjustments or repairs on a Safety Valve? - Correct
Answer-Qualify person from Manufacturer or Representative
What mechanical device is used to remove scale from water Tubes? -
Correct Answer-A Tube Turbine is used
In a duct air handling system, space thermostat control building
temperatures by? - Correct Answer-Mixing the air from hot & cold duct
in a mixing box serving the space
The removal of moisture from air using a cooling coil is called
_________ dehumidification? - Correct Answer-Passive
In a multi-zone air handler unit, the zone thermostat controls the zone
temperature by? - Correct Answer-Dampers that control the air flow
from the hot & cold duct
4|Page
Stationary Engineer, Station Engineer Exam, Dc 1st Class Boiler
Study Guide Exam Prep
DC 3RD CLASS TEST, 3RD CLASS STATIONARY STEAM ENGINEER
LICENSE PREP, STATIONARY ENGINEER, STATION ENGINEER EXAM, DC
1ST CLASS BOILER STUDY GUIDE EXAM PREP NEWEST 2026/2027
ACTUAL EXAM COMPLETE QUESTIONS AND CORRECT DETAILED
ANSWERS (VERIFIED ANSWERS) |ALREADY GRADED A+||BRAND NEW
VERSION!!
What is the first thing to do when shutting down a boiler? - Correct
Answer-To turn off the fire
A flow control should be blown down when? - Correct Answer-once per
shift
How often should you check the Low Water Fuel Cut off? - Correct
Answer-once per shift
Why is oil added to the refrigerant? - Correct Answer-lubrication of the
compressor
Keep refrigerant migrating
1|Page
, Dc 3rd Class Test, 3rd Class Stationary Steam Engineer License Prep,
Stationary Engineer, Station Engineer Exam, Dc 1st Class Boiler
Study Guide Exam Prep
Recycled and filtered refrigerant can be used where? - Correct Answer-
By the same owner in the same type of equipment
Data printed on the equipment nameplate would include manufacturer,
model, and serial number and________________? - Correct Answer-
Stamp of approval from commissioning authority
How many BTU's does it take to raise 10 lbs of steam from 40 to 41
degrees? - Correct Answer-1 BTU
When working on a boiler, permits should be required? - Correct
Answer-For every shift
How many things do safety controls protect against? - Correct Answer-
Over pressure
Over Heating
Fire side explosions
What chemical compounds in water cause permanent hardness? -
Correct Answer-Calcium Sulfate and Magnesium Silicate
2|Page
, Dc 3rd Class Test, 3rd Class Stationary Steam Engineer License Prep,
Stationary Engineer, Station Engineer Exam, Dc 1st Class Boiler
Study Guide Exam Prep
What chemicals are used to combat corrosion? - Correct Answer-
sodium sulfite and hydrazine
You have boiler water that is found to have a PH of 5. What compound
do you add to neutralize? - Correct Answer-bases
What produces soft scale? - Correct Answer-calcium carbonate and
magnesium carbonate
With normal oxygen and low alkalinity, what is added to boiler water? -
Correct Answer-Neutralizing Amines
What is hard forming scale? - Correct Answer-silica
Which chemicals are used to combat scale? - Correct Answer-Combined
Phosphate Treatment
Which compound is not heat produce? - Correct Answer-Nitrogen
What takes no actual action in combustion? - Correct Answer-Nitrogen
3|Page
, Dc 3rd Class Test, 3rd Class Stationary Steam Engineer License Prep,
Stationary Engineer, Station Engineer Exam, Dc 1st Class Boiler
Study Guide Exam Prep
With hydroxide present & normal oxygen levels; which chemical will
cause problems? - Correct Answer-Chlorine
What mechanical device is used to remove scale from Fire Tubes? -
Correct Answer-A Tube Rattler or Vibrator is used
Who can make Adjustments or repairs on a Safety Valve? - Correct
Answer-Qualify person from Manufacturer or Representative
What mechanical device is used to remove scale from water Tubes? -
Correct Answer-A Tube Turbine is used
In a duct air handling system, space thermostat control building
temperatures by? - Correct Answer-Mixing the air from hot & cold duct
in a mixing box serving the space
The removal of moisture from air using a cooling coil is called
_________ dehumidification? - Correct Answer-Passive
In a multi-zone air handler unit, the zone thermostat controls the zone
temperature by? - Correct Answer-Dampers that control the air flow
from the hot & cold duct
4|Page
