1. Q: What is the purpose of a boiler? ANSWER A boiler is a closed vessel
designed to heat water or generate steam by applying heat energy from
combustion or other sources for heating or power generation.
2. Q: What is the normal operating pressure range for low-pressure
boilers? ANSWER Low-pressure steam boilers operate at or below 15 psig,
and hot water boilers operate at or below 160 psig with temperatures not
exceeding 250°F.
3. Q: Define high-pressure boiler. ANSWER A high-pressure boiler operates
above 15 psig for steam or above 160 psig and/or 250°F for hot water.
4. Q: What is boiler horsepower? ANSWER One boiler horsepower equals
the evaporation of 34.5 pounds of water per hour from and at 212°F, which is
equivalent to 33,475 BTU/hr.
5. Q: What is the purpose of a fusible plug? ANSWER A fusible plug is a
safety device that melts at a predetermined temperature to warn of low water
conditions and prevent boiler overheating.
6. Q: Where should a fusible plug be installed? ANSWER It should be
installed in the furnace sheet or crown sheet where it will be covered with water
under normal operating conditions but exposed to heat if water level drops
dangerously low.
7. Q: What is the function of a safety valve? ANSWER A safety valve
automatically relieves pressure when it exceeds the maximum allowable
working pressure, preventing boiler overpressure and potential explosion.
,8. Q: How often should safety valves be tested? ANSWER Safety valves
should be tested at least once per shift or daily to ensure proper operation and
prevent sticking.
9. Q: What is the purpose of a water column? ANSWER A water column
provides a stable location for mounting water level indicators and controls,
isolated from turbulent water in the boiler drum.
10. Q: What is carryover in boiler operations? ANSWER Carryover is the
entrainment of boiler water droplets with steam, causing moisture and
impurities to be carried into the steam system.
11. Q: What causes priming in a boiler? ANSWER Priming is caused by
excessive water level, rapid load changes, high water alkalinity, or excessive
dissolved solids causing foaming.
12. Q: What is the difference between priming and foaming? ANSWER
Priming is mechanical carryover of water droplets due to turbulence, while
foaming is caused by surface tension effects from dissolved solids creating
stable bubbles.
13. Q: What is blowdown? ANSWER Blowdown is the process of removing
water from a boiler to control concentrations of dissolved solids and suspended
matter.
14. Q: Why is bottom blowdown performed? ANSWER Bottom blowdown
removes accumulated sediment, sludge, and concentrated dissolved solids from
the lowest part of the boiler.
15. Q: What is surface blowdown? ANSWER Surface blowdown (or
skimming) removes water from the surface where floating oils and dissolved
solids concentrate.
16. Q: How do you calculate boiler efficiency? ANSWER Boiler efficiency
= (Heat output / Heat input) × 100, or (Steam energy - Feedwater energy) / Fuel
energy × 100.
17. Q: What is a fire tube boiler? ANSWER A fire tube boiler has hot gases
passing through tubes surrounded by water, with the fire and gases inside the
tubes.
18. Q: What is a water tube boiler? ANSWER A water tube boiler has water
circulating through tubes that are surrounded by hot combustion gases.
, 19. Q: What are the advantages of water tube boilers? ANSWER Higher
pressures and capacities, faster steam raising, better circulation, safer operation,
and easier inspection and repair.
20. Q: What is the purpose of a steam drum? ANSWER The steam drum
separates steam from water, provides steam storage, contains steam purification
equipment, and serves as a header for downcomers.
21. Q: What is a mud drum? ANSWER A mud drum is the lower drum in a
water tube boiler where sediment collects and from which bottom blowdown is
taken.
22. Q: What is circulation ratio in a boiler? ANSWER Circulation ratio is
the ratio of water circulated through generating tubes to the amount of steam
produced, typically 4:1 to 25:1.
23. Q: What causes tube failure in boilers? ANSWER Overheating,
corrosion, erosion, scale buildup, poor water treatment, mechanical damage,
thermal stress, and water hammer.
24. Q: What is a superheater? ANSWER A superheater is a heat exchanger
that raises steam temperature above saturation temperature at a given pressure.
25. Q: What is the purpose of an economizer? ANSWER An economizer
recovers waste heat from flue gases to preheat boiler feedwater, improving
overall efficiency.
26. Q: What is an air preheater? ANSWER An air preheater uses waste heat
from flue gases to heat combustion air before it enters the furnace, improving
efficiency.
27. Q: What is meant by boiler trim? ANSWER Boiler trim refers to the
gauges, controls, and accessories mounted on a boiler including pressure gauge,
water level indicators, and safety valves.
28. Q: What is the minimum number of water level indicators required?
ANSWER At least two independent water level indicators are required on
every boiler for redundancy and safety.
29. Q: What is a try cock? ANSWER A try cock is a valve used to verify
water level by observing whether steam or water discharges when opened.
30. Q: Where should try cocks be located? ANSWER At minimum, one at
normal water level, one above, and one below, spaced to indicate safe operating
range.
designed to heat water or generate steam by applying heat energy from
combustion or other sources for heating or power generation.
2. Q: What is the normal operating pressure range for low-pressure
boilers? ANSWER Low-pressure steam boilers operate at or below 15 psig,
and hot water boilers operate at or below 160 psig with temperatures not
exceeding 250°F.
3. Q: Define high-pressure boiler. ANSWER A high-pressure boiler operates
above 15 psig for steam or above 160 psig and/or 250°F for hot water.
4. Q: What is boiler horsepower? ANSWER One boiler horsepower equals
the evaporation of 34.5 pounds of water per hour from and at 212°F, which is
equivalent to 33,475 BTU/hr.
5. Q: What is the purpose of a fusible plug? ANSWER A fusible plug is a
safety device that melts at a predetermined temperature to warn of low water
conditions and prevent boiler overheating.
6. Q: Where should a fusible plug be installed? ANSWER It should be
installed in the furnace sheet or crown sheet where it will be covered with water
under normal operating conditions but exposed to heat if water level drops
dangerously low.
7. Q: What is the function of a safety valve? ANSWER A safety valve
automatically relieves pressure when it exceeds the maximum allowable
working pressure, preventing boiler overpressure and potential explosion.
,8. Q: How often should safety valves be tested? ANSWER Safety valves
should be tested at least once per shift or daily to ensure proper operation and
prevent sticking.
9. Q: What is the purpose of a water column? ANSWER A water column
provides a stable location for mounting water level indicators and controls,
isolated from turbulent water in the boiler drum.
10. Q: What is carryover in boiler operations? ANSWER Carryover is the
entrainment of boiler water droplets with steam, causing moisture and
impurities to be carried into the steam system.
11. Q: What causes priming in a boiler? ANSWER Priming is caused by
excessive water level, rapid load changes, high water alkalinity, or excessive
dissolved solids causing foaming.
12. Q: What is the difference between priming and foaming? ANSWER
Priming is mechanical carryover of water droplets due to turbulence, while
foaming is caused by surface tension effects from dissolved solids creating
stable bubbles.
13. Q: What is blowdown? ANSWER Blowdown is the process of removing
water from a boiler to control concentrations of dissolved solids and suspended
matter.
14. Q: Why is bottom blowdown performed? ANSWER Bottom blowdown
removes accumulated sediment, sludge, and concentrated dissolved solids from
the lowest part of the boiler.
15. Q: What is surface blowdown? ANSWER Surface blowdown (or
skimming) removes water from the surface where floating oils and dissolved
solids concentrate.
16. Q: How do you calculate boiler efficiency? ANSWER Boiler efficiency
= (Heat output / Heat input) × 100, or (Steam energy - Feedwater energy) / Fuel
energy × 100.
17. Q: What is a fire tube boiler? ANSWER A fire tube boiler has hot gases
passing through tubes surrounded by water, with the fire and gases inside the
tubes.
18. Q: What is a water tube boiler? ANSWER A water tube boiler has water
circulating through tubes that are surrounded by hot combustion gases.
, 19. Q: What are the advantages of water tube boilers? ANSWER Higher
pressures and capacities, faster steam raising, better circulation, safer operation,
and easier inspection and repair.
20. Q: What is the purpose of a steam drum? ANSWER The steam drum
separates steam from water, provides steam storage, contains steam purification
equipment, and serves as a header for downcomers.
21. Q: What is a mud drum? ANSWER A mud drum is the lower drum in a
water tube boiler where sediment collects and from which bottom blowdown is
taken.
22. Q: What is circulation ratio in a boiler? ANSWER Circulation ratio is
the ratio of water circulated through generating tubes to the amount of steam
produced, typically 4:1 to 25:1.
23. Q: What causes tube failure in boilers? ANSWER Overheating,
corrosion, erosion, scale buildup, poor water treatment, mechanical damage,
thermal stress, and water hammer.
24. Q: What is a superheater? ANSWER A superheater is a heat exchanger
that raises steam temperature above saturation temperature at a given pressure.
25. Q: What is the purpose of an economizer? ANSWER An economizer
recovers waste heat from flue gases to preheat boiler feedwater, improving
overall efficiency.
26. Q: What is an air preheater? ANSWER An air preheater uses waste heat
from flue gases to heat combustion air before it enters the furnace, improving
efficiency.
27. Q: What is meant by boiler trim? ANSWER Boiler trim refers to the
gauges, controls, and accessories mounted on a boiler including pressure gauge,
water level indicators, and safety valves.
28. Q: What is the minimum number of water level indicators required?
ANSWER At least two independent water level indicators are required on
every boiler for redundancy and safety.
29. Q: What is a try cock? ANSWER A try cock is a valve used to verify
water level by observing whether steam or water discharges when opened.
30. Q: Where should try cocks be located? ANSWER At minimum, one at
normal water level, one above, and one below, spaced to indicate safe operating
range.
