SAFE BOILER OPERATION
FUNDAMENTALS—SPECIAL
ENGINEER'S GUIDE FOR THE STATE
OF MINNESOTA(GRADED A+)
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
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
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.
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
Dryback boiler - ANSWERType of firetube boiler. Has a dry turnaround chamber,
easier inspection and maintenance
Wetback boiler - ANSWERType of firetube boiler. Water enclosed back end that
redirects gases, more efficient and require less maintenance
HRT - ANSWERHorizontal Return Tubular
HRT Boiler - ANSWERA firetube boiler with the tubes running horizontally,
suspended over a furnace
Industrial watertube boiler - ANSWERConsists of a steam drum and a mud drum
Commercial watertube boiler - ANSWERProduces steam/hot water for
commercial/med size applications, there are straight tube, bent tube, and membrane
watertube types
Cast iron boiler - ANSWERGas flows around cast iron sections that contain water
and direct it around the internal flame. They are limited to low pressure steam or hot
water applications
Accumulation Test - ANSWERTests relief and safety relief valves under firing
conditions
LWCO - ANSWERLow water fuel cut off
Low Water Fuel Cutoff - ANSWERCuts the fuel supply to the boiler if the water level
goes beneath the lowest permissible level. There are float and probe type cut offs.
The LWCO should be tested at least once a week.
FUNDAMENTALS—SPECIAL
ENGINEER'S GUIDE FOR THE STATE
OF MINNESOTA(GRADED A+)
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
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
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.
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
Dryback boiler - ANSWERType of firetube boiler. Has a dry turnaround chamber,
easier inspection and maintenance
Wetback boiler - ANSWERType of firetube boiler. Water enclosed back end that
redirects gases, more efficient and require less maintenance
HRT - ANSWERHorizontal Return Tubular
HRT Boiler - ANSWERA firetube boiler with the tubes running horizontally,
suspended over a furnace
Industrial watertube boiler - ANSWERConsists of a steam drum and a mud drum
Commercial watertube boiler - ANSWERProduces steam/hot water for
commercial/med size applications, there are straight tube, bent tube, and membrane
watertube types
Cast iron boiler - ANSWERGas flows around cast iron sections that contain water
and direct it around the internal flame. They are limited to low pressure steam or hot
water applications
Accumulation Test - ANSWERTests relief and safety relief valves under firing
conditions
LWCO - ANSWERLow water fuel cut off
Low Water Fuel Cutoff - ANSWERCuts the fuel supply to the boiler if the water level
goes beneath the lowest permissible level. There are float and probe type cut offs.
The LWCO should be tested at least once a week.
