1|Page
DC 3rd Class Test, 3rd Class Stationary
Steam Engineer License Prep,
Stationary Engineer, Station Engineer
Exam, DC 1st Class Boiler| Certified Q&A
2026
A replacement refrigerant for R-12 medium and high temperature refrigeration
application is _____? - correct-answer -134 A
The color for an R-134 a refrigerant cylinder is _______? - correct-answer -light
blue
The color for an R-410 a refrigerant cylinder is _______? - correct-answer -rose
Which of the following is a hanged joint between two or more furnaces and may
be located in the center of the furnace, with no more than 18-inches an apart? -
correct-answer -Adamson Ring
,2|Page
Which of the following statement is true concerning fire tube and water tube
boilers? - correct-answer -A water tube boiler's biggest advantage over a fire tube
boiler___? ____flexibility to increase capacities and pressure.
A chief engineer is preparing for a mud drum inspection, which of the following
will you not do? - correct-answer -Set up a 110 volt lighting for inspection
What do you use to bank off a boiler and bring it back online without using the
shut off valve? - correct-answer -Automatic stop valve
What is not an advantage of an economic boiler over a conventional HRT Boiler? -
correct-answer -Space, ability to increase capacity, flexibility,
What do you call the chemicals that are used to test water for hardness? - correct-
answer -Reagents
What are the three "T"s of combustion stand for? - correct-answer -Time,
Temperature, Turbulence
,3|Page
What do you do to attain complete combustion in a boiler? - correct-answer -
Increase secondary air
Air leaking into the inner and outer of the boiler, what will happen? - correct-
answer -Decrease boiler efficiency
By clicking on the exibit the picture is a display of (page 365 BOG)? - correct-
answer -Full nozzle reaction type safety valve
What controls the steam pressure and monitors the combustion air intake? -
correct-answer -Fuel, air, water
What happens to the water in a boiler that is at 80% load and all of a sudden, the
flame goes off? - correct-answer -Water will shrink and cause a low water
condition
What is installed between the boiler drum and the steam gauge to create a
protective water tight seal for the gauge? - correct-answer -Siphon
, 4|Page
What is the replacement refrigerant for R-22? - correct-answer -R-410 A
Which valves to the boiler is opened ______ and closed ______ during blow
down? - correct-answer -By opening the Quick opening valve first and closing it
Last.
How and why tube ends on a fire tube boiler are secure? - correct-answer -Tube
ends are beaded to allow for greater expansion and control of the tubes
What is not an advantage of the economic type boiler over the conventional type
boiler? - correct-answer -Allows greater flexibility expansion and contraction
An accelerated circulation water tube is one characterized by? - correct-answer -
Heated down comers
Why is platinum used in RTD (Resistive temperature Device)? - correct-answer -
Because of its stability at high temperature
DC 3rd Class Test, 3rd Class Stationary
Steam Engineer License Prep,
Stationary Engineer, Station Engineer
Exam, DC 1st Class Boiler| Certified Q&A
2026
A replacement refrigerant for R-12 medium and high temperature refrigeration
application is _____? - correct-answer -134 A
The color for an R-134 a refrigerant cylinder is _______? - correct-answer -light
blue
The color for an R-410 a refrigerant cylinder is _______? - correct-answer -rose
Which of the following is a hanged joint between two or more furnaces and may
be located in the center of the furnace, with no more than 18-inches an apart? -
correct-answer -Adamson Ring
,2|Page
Which of the following statement is true concerning fire tube and water tube
boilers? - correct-answer -A water tube boiler's biggest advantage over a fire tube
boiler___? ____flexibility to increase capacities and pressure.
A chief engineer is preparing for a mud drum inspection, which of the following
will you not do? - correct-answer -Set up a 110 volt lighting for inspection
What do you use to bank off a boiler and bring it back online without using the
shut off valve? - correct-answer -Automatic stop valve
What is not an advantage of an economic boiler over a conventional HRT Boiler? -
correct-answer -Space, ability to increase capacity, flexibility,
What do you call the chemicals that are used to test water for hardness? - correct-
answer -Reagents
What are the three "T"s of combustion stand for? - correct-answer -Time,
Temperature, Turbulence
,3|Page
What do you do to attain complete combustion in a boiler? - correct-answer -
Increase secondary air
Air leaking into the inner and outer of the boiler, what will happen? - correct-
answer -Decrease boiler efficiency
By clicking on the exibit the picture is a display of (page 365 BOG)? - correct-
answer -Full nozzle reaction type safety valve
What controls the steam pressure and monitors the combustion air intake? -
correct-answer -Fuel, air, water
What happens to the water in a boiler that is at 80% load and all of a sudden, the
flame goes off? - correct-answer -Water will shrink and cause a low water
condition
What is installed between the boiler drum and the steam gauge to create a
protective water tight seal for the gauge? - correct-answer -Siphon
, 4|Page
What is the replacement refrigerant for R-22? - correct-answer -R-410 A
Which valves to the boiler is opened ______ and closed ______ during blow
down? - correct-answer -By opening the Quick opening valve first and closing it
Last.
How and why tube ends on a fire tube boiler are secure? - correct-answer -Tube
ends are beaded to allow for greater expansion and control of the tubes
What is not an advantage of the economic type boiler over the conventional type
boiler? - correct-answer -Allows greater flexibility expansion and contraction
An accelerated circulation water tube is one characterized by? - correct-answer -
Heated down comers
Why is platinum used in RTD (Resistive temperature Device)? - correct-answer -
Because of its stability at high temperature
