SAFE BOILER OPERATION
FUNDAMENTALS—SPECIAL
ENGINEER'S GUIDE FOR THE STATE
OF MINNESOTA CORRECT 100%
first law of thermodynamics - ANSWEREnergy cannot be created or destroyed
second law of thermodynamics - ANSWERHeat flows from a higher temperature
material to a lower temperature material
How does the boiling point of water change with steam pressure? - ANSWERThe
boiling point of water increases as steam pressure increases
latent heat - ANSWERHeat that causes a state change but doesn't change the
temperature
sensible heat - ANSWERHeat that causes a temperature change without a state
change
Conduction - ANSWERThe direct transfer of heat from one substance to another
substance that it is touching.
Convection - ANSWERThe transfer of heat by the movement of a fluid
Radiation - ANSWEREnergy that is radiated or transmitted in the form of rays or waves
or particles. Produced upon contact with opaque objects
What are examples of conduction, convection, and radiation in a boiler? -
ANSWERHeat radiates from combustion flames to the metal surfaces of the boiler, the
metal surfaces conduct heat from the hot side to the cooler side where metal is covered
by water or steam. Heat moves within the steam/hot water via convection.
Firetube boiler - ANSWERA boiler with tubes of combustion gases passing through the
water space.
Watertube boiler - ANSWERA boiler in which water passes through tubes surrounded
by gases of combustion. It provides greater horsepower, steam volume, and pressures.
Low pressure steam heating boiler - ANSWERSteam is supplied at pressures up to 15
psi
, Low Pressure Hot Water Heating Boiler - ANSWERSupplies hot water at pressure up to
160 psi and a T less than 250°F
Hot Water Supply Boiler - ANSWERFor space heating at pressures of not more than
160 psi and T under 210°F
Power Hot Water Boiler - ANSWERHeats liquid to a p greater than 160 psi or a T
greater than 250°F
Power Steam Boiler - ANSWERSteam is generated at p > 15psi
Low Pressure Steam Boiler - ANSWERMAWP < 15 psi
High pressure steam boiler - ANSWERMAWP > 15 psi
Boiler Horsepower (BHP) definition - ANSWERHeat required to evaporate 34.5 lb/hr
water from and at a T of 212°F
BHP in Btu/hr - ANSWER33,472 Btu/hr
How does water circulation in a firetube boiler work? - ANSWERWater is heated by the
firetubes, which decreases its density, causing it to rise and circulating cooler, more
dense water down to be heated
Electrode Electric Boiler - ANSWERHeat is generated by an arc produced by an electric
current flowing from one electrode to another — effective in responding to demand
Resistance Electric Boiler - ANSWERElectricity flows through resistive elements.
Resistance generated heat. REBs are generally low capacity boilers and less effective
than other boilers
A hot water heating system... - ANSWER...heats more evenly than steam heating
systems
Natural circulation hot water heating system - ANSWERAn open system that uses the
difference in the density between hot and cool water to move it through the system.
Utilizes an expansion tank above the heating units to maintain a constant pressure in
the system.
Forced circulation hot water heating system - ANSWERClosed system that uses a
circulating pump to move hot water through the heating system and the pressure is
maintained through a compression tank. Operate at a pressure > 1 atm and requires no
venting.
FUNDAMENTALS—SPECIAL
ENGINEER'S GUIDE FOR THE STATE
OF MINNESOTA CORRECT 100%
first law of thermodynamics - ANSWEREnergy cannot be created or destroyed
second law of thermodynamics - ANSWERHeat flows from a higher temperature
material to a lower temperature material
How does the boiling point of water change with steam pressure? - ANSWERThe
boiling point of water increases as steam pressure increases
latent heat - ANSWERHeat that causes a state change but doesn't change the
temperature
sensible heat - ANSWERHeat that causes a temperature change without a state
change
Conduction - ANSWERThe direct transfer of heat from one substance to another
substance that it is touching.
Convection - ANSWERThe transfer of heat by the movement of a fluid
Radiation - ANSWEREnergy that is radiated or transmitted in the form of rays or waves
or particles. Produced upon contact with opaque objects
What are examples of conduction, convection, and radiation in a boiler? -
ANSWERHeat radiates from combustion flames to the metal surfaces of the boiler, the
metal surfaces conduct heat from the hot side to the cooler side where metal is covered
by water or steam. Heat moves within the steam/hot water via convection.
Firetube boiler - ANSWERA boiler with tubes of combustion gases passing through the
water space.
Watertube boiler - ANSWERA boiler in which water passes through tubes surrounded
by gases of combustion. It provides greater horsepower, steam volume, and pressures.
Low pressure steam heating boiler - ANSWERSteam is supplied at pressures up to 15
psi
, Low Pressure Hot Water Heating Boiler - ANSWERSupplies hot water at pressure up to
160 psi and a T less than 250°F
Hot Water Supply Boiler - ANSWERFor space heating at pressures of not more than
160 psi and T under 210°F
Power Hot Water Boiler - ANSWERHeats liquid to a p greater than 160 psi or a T
greater than 250°F
Power Steam Boiler - ANSWERSteam is generated at p > 15psi
Low Pressure Steam Boiler - ANSWERMAWP < 15 psi
High pressure steam boiler - ANSWERMAWP > 15 psi
Boiler Horsepower (BHP) definition - ANSWERHeat required to evaporate 34.5 lb/hr
water from and at a T of 212°F
BHP in Btu/hr - ANSWER33,472 Btu/hr
How does water circulation in a firetube boiler work? - ANSWERWater is heated by the
firetubes, which decreases its density, causing it to rise and circulating cooler, more
dense water down to be heated
Electrode Electric Boiler - ANSWERHeat is generated by an arc produced by an electric
current flowing from one electrode to another — effective in responding to demand
Resistance Electric Boiler - ANSWERElectricity flows through resistive elements.
Resistance generated heat. REBs are generally low capacity boilers and less effective
than other boilers
A hot water heating system... - ANSWER...heats more evenly than steam heating
systems
Natural circulation hot water heating system - ANSWERAn open system that uses the
difference in the density between hot and cool water to move it through the system.
Utilizes an expansion tank above the heating units to maintain a constant pressure in
the system.
Forced circulation hot water heating system - ANSWERClosed system that uses a
circulating pump to move hot water through the heating system and the pressure is
maintained through a compression tank. Operate at a pressure > 1 atm and requires no
venting.
