NEWEST 2024 DC BOILER EXAM PREP (FORMULAS AND
CONSTANTS USED FOR THE DC 3RD CLASS BOILER
EXAM) COMPLETE ACTUAL EXAM QUESTIONS AND
CORRECT DETAILED ANSWERS (100% CORRECT
VERIFIED ANSWERS) LATEST UPDATES |ALREADY
GRADED A+ (FULL REVISED EXAM)
Moving blading in which space between blades is the same size at the blading inlet,
and the blading outlet. - ANSWER: Impulse Blading
To blowdown a boiler equipped with a quick opening and slow opening valve on the
bottom blowdown line, the_________. - ANSWER: quick opening valve is opened
first and closed last.
Hardness of water is the measurement in ppm of ________ and ________ in the
water. - ANSWER: calcium and magnesium
A pump delivers 175 gallons per minute against a pressure of 55 psi; the suction
pressure is 15 psi. If a pump is 80% efficient, what is the horsepower needed? -
ANSWER: HP=5.1 HP= (Head in Feet) x (Weight in Lbs.)/ 33,000 x Efficiency
a duplex double-acting reciprocating feed water pump has____ - ANSWER: two
steam Pistons 2 to 2 2/2 times larger in area than the water piston
Name a technique to control the nitrous oxide emissions. - ANSWER: Selective
Catalytic Reduction
Spalling in a boiler occurs in the ____? - ANSWER: Combustion chamber
A technology in which solid waste is heated in an oxygen starved atmosphere to
break down the solids into a gas is called ______? - ANSWER: Pyrolysis
What is the primary purpose of using wet scrubbers? - ANSWER: To remove sulfur
dioxides
The thermal efficiency of a boiler with a stack temperature of 750°F and and a
furnace temperature of 3200°F is_______? - ANSWER: 75% ((3200-750)/3200) x 100
________is a water-purification process in which the water to be treated is
pressurized and applied against the surface of a semipermeable membrane. -
ANSWER: Reverse osmosis
The airflow switch at the burner fan housing______. - ANSWER: Ensures the primary
air fan is functioning
, How many inches of steam space in a cylinder of an engine 12"x28" and the stroke is
5/8 of its full travel? - ANSWER: 1978. V=AxL V=3.14(6x6)x28x.625= 1978
What is the horsepower requirement of a pump that moves 2500 gpm of water
against a head of 475' if the pump is operating at 58% efficiency? - ANSWER: 516.8
HP=Head x Weight/33000 x efficiency. (Head =475, Weight = 2500gpm x 8.33) (475x
20825)/19140
A ______ is the condition that is being controlled - ANSWER: process variable
Although boiler tubes and boiler drums withstand the same pressure, the walls of
the boiler tubes are much thinner because ______. - ANSWER: The tubes are much
smaller in diameter
A lead sulfide cell detects_____. - ANSWER: Burner pilot and main flame
Which of the following indicates a malfunction in the DC heater? 1. The boiler
requires excessive amounts of oxygen absorbing chemicals.
2.Water and steam are entering the DC heater at the same temperature. - ANSWER:
Both 1 & 2
______ is the plasticity exhibited by a material under tension loading. - ANSWER:
Ductility
In a pressure atomizing fuel oil-burner, atomization of fuel is produced by the
_______. - ANSWER: Burner tip and high pressure fuel
The ends of boiler tubes are secured to headers by______. - ANSWER: Expanding
A_______ is a process condition that must be met before a certain action may be
taken. - ANSWER: Permissive
______ is the ability of a material to return to its original shape after being
deformed. - ANSWER: Resiliency
In a three-element feedwater regulating system, __________ are measured. -
ANSWER: steam flow, feedwater flow, and water level
A ________ is a highly efficient ion-exchange process in which resin is regenerated
with sulfuric acid in the first vessel and caustic soda in the second vessel - ANSWER:
demineralizer
The purpose of the diffuser in a boiler burner assembly is to ______. - ANSWER:
shield the flame from the incoming air blast while allowing some mixing of fuel and
air
CONSTANTS USED FOR THE DC 3RD CLASS BOILER
EXAM) COMPLETE ACTUAL EXAM QUESTIONS AND
CORRECT DETAILED ANSWERS (100% CORRECT
VERIFIED ANSWERS) LATEST UPDATES |ALREADY
GRADED A+ (FULL REVISED EXAM)
Moving blading in which space between blades is the same size at the blading inlet,
and the blading outlet. - ANSWER: Impulse Blading
To blowdown a boiler equipped with a quick opening and slow opening valve on the
bottom blowdown line, the_________. - ANSWER: quick opening valve is opened
first and closed last.
Hardness of water is the measurement in ppm of ________ and ________ in the
water. - ANSWER: calcium and magnesium
A pump delivers 175 gallons per minute against a pressure of 55 psi; the suction
pressure is 15 psi. If a pump is 80% efficient, what is the horsepower needed? -
ANSWER: HP=5.1 HP= (Head in Feet) x (Weight in Lbs.)/ 33,000 x Efficiency
a duplex double-acting reciprocating feed water pump has____ - ANSWER: two
steam Pistons 2 to 2 2/2 times larger in area than the water piston
Name a technique to control the nitrous oxide emissions. - ANSWER: Selective
Catalytic Reduction
Spalling in a boiler occurs in the ____? - ANSWER: Combustion chamber
A technology in which solid waste is heated in an oxygen starved atmosphere to
break down the solids into a gas is called ______? - ANSWER: Pyrolysis
What is the primary purpose of using wet scrubbers? - ANSWER: To remove sulfur
dioxides
The thermal efficiency of a boiler with a stack temperature of 750°F and and a
furnace temperature of 3200°F is_______? - ANSWER: 75% ((3200-750)/3200) x 100
________is a water-purification process in which the water to be treated is
pressurized and applied against the surface of a semipermeable membrane. -
ANSWER: Reverse osmosis
The airflow switch at the burner fan housing______. - ANSWER: Ensures the primary
air fan is functioning
, How many inches of steam space in a cylinder of an engine 12"x28" and the stroke is
5/8 of its full travel? - ANSWER: 1978. V=AxL V=3.14(6x6)x28x.625= 1978
What is the horsepower requirement of a pump that moves 2500 gpm of water
against a head of 475' if the pump is operating at 58% efficiency? - ANSWER: 516.8
HP=Head x Weight/33000 x efficiency. (Head =475, Weight = 2500gpm x 8.33) (475x
20825)/19140
A ______ is the condition that is being controlled - ANSWER: process variable
Although boiler tubes and boiler drums withstand the same pressure, the walls of
the boiler tubes are much thinner because ______. - ANSWER: The tubes are much
smaller in diameter
A lead sulfide cell detects_____. - ANSWER: Burner pilot and main flame
Which of the following indicates a malfunction in the DC heater? 1. The boiler
requires excessive amounts of oxygen absorbing chemicals.
2.Water and steam are entering the DC heater at the same temperature. - ANSWER:
Both 1 & 2
______ is the plasticity exhibited by a material under tension loading. - ANSWER:
Ductility
In a pressure atomizing fuel oil-burner, atomization of fuel is produced by the
_______. - ANSWER: Burner tip and high pressure fuel
The ends of boiler tubes are secured to headers by______. - ANSWER: Expanding
A_______ is a process condition that must be met before a certain action may be
taken. - ANSWER: Permissive
______ is the ability of a material to return to its original shape after being
deformed. - ANSWER: Resiliency
In a three-element feedwater regulating system, __________ are measured. -
ANSWER: steam flow, feedwater flow, and water level
A ________ is a highly efficient ion-exchange process in which resin is regenerated
with sulfuric acid in the first vessel and caustic soda in the second vessel - ANSWER:
demineralizer
The purpose of the diffuser in a boiler burner assembly is to ______. - ANSWER:
shield the flame from the incoming air blast while allowing some mixing of fuel and
air
