4AE3 U11 C5 Review
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Questions and Answers

What is a limitation of flexible tube and coil tube type watertube boilers?

  • They require special foundation.
  • They require more monitoring for proper water treatment. (correct)
  • They are not compact.
  • They need more maintenance compared to firetube boilers.

    • Why are flexible tube and coil tube type watertube boilers safer than firetube boilers?

  • They have a larger capacity.
  • They contain very little potential energy stored in their water. (correct)
  • They are more corrosion resistant.
  • They have more refractory.

    • What is a benefit of cast iron sectional boilers?

  • They are easier to disassemble.
  • They are more corrosion resistant than steel boilers. (correct)
  • They require highly skilled labour.
  • They are less compact.

    • What is an advantage of flexible tube and coil tube type watertube boilers compared to firetube boilers?

    <p>They are more compact and lighter.</p> Signup and view all the answers

    Why are flexible tube and coil tube type watertube boilers a good choice for smaller heating plants?

    <p>They are more compact and lighter.</p> Signup and view all the answers

    What is a characteristic of flexible tube and coil tube type watertube boilers?

    <p>They develop little thermally induced stress.</p> Signup and view all the answers

    What is the primary advantage of the coil tube boiler's arrangement?

    <p>Increased heat transfer due to turbulent flow</p> Signup and view all the answers

    What type of tubing is commonly used in steam boiler varieties?

    <p>Steel</p> Signup and view all the answers

    What is a critical aspect of water treatment in coil tube boilers?

    <p>Preventing scale deposition</p> Signup and view all the answers

    What is the typical material used in the construction of cast iron sectional boilers?

    <p>Cast iron</p> Signup and view all the answers

    What is the purpose of the push nipples in cast iron sectional boilers?

    <p>To create a seal between the sections</p> Signup and view all the answers

    In a coil tube boiler, what is the function of the pump?

    <p>To circulate water through the coil</p> Signup and view all the answers

    What is the benefit of using copper tubing in coil tube boilers?

    <p>It has a higher heat transfer rate than steel</p> Signup and view all the answers

    What is the typical configuration of the sections in a horizontal sectional cast iron boiler?

    <p>Stacked one above the other like pancakes</p> Signup and view all the answers

    What is the purpose of the collector hood in a cast iron sectional boiler?

    <p>To guide the hot gases to the vent connector</p> Signup and view all the answers

    What is the common application of coil tube boilers?

    <p>Hot water supply and heating systems</p> Signup and view all the answers

    What is an advantage of cast iron sectional boilers?

    <p>They can be increased in capacity by installing more sections.</p> Signup and view all the answers

    Why are industrial type watertube boilers seldom selected for low-pressure heating plants?

    <p>They are more expensive than cast iron or steel firetube boilers.</p> Signup and view all the answers

    What is the purpose of the mud drum and steam drum in a bent tube watertube boiler?

    <p>To return cooler water and supply hot water</p> Signup and view all the answers

    How do the furnace walls in a bent tube watertube boiler absorb heat?

    <p>By radiation from the fire</p> Signup and view all the answers

    What is the purpose of the outer membrane walls in a bent tube watertube boiler?

    <p>To form a passageway for the flue gases</p> Signup and view all the answers

    What is the advantage of the flexible watertube boiler design?

    <p>All of the above</p> Signup and view all the answers

    Why are bent tube watertube boilers popular for use as heating boilers?

    <p>They are designed for low-pressure steam or hot water service</p> Signup and view all the answers

    What is the purpose of the circulation pump in a hot water application?

    <p>To force the water through the boiler</p> Signup and view all the answers

    What is the purpose of the insulated steel casing in a bent tube watertube boiler?

    <p>To enclose the boiler and reduce heat loss</p> Signup and view all the answers

    What is the result of the combustion gases traveling between the inner and outer membrane walls in a bent tube watertube boiler?

    <p>They transfer heat to the walls by convection</p> Signup and view all the answers

    What is the main purpose of the removable panels in the casing of cast iron boilers?

    <p>To provide access to the boiler sections and flue gas passageways</p> Signup and view all the answers

    What is the primary method of increasing heat transfer in cast iron boiler sections?

    <p>Exposing as large a surface as possible to the hot gases</p> Signup and view all the answers

    What is the purpose of the extended surfaces on the cast iron boiler sections?

    <p>To increase the heating surface area</p> Signup and view all the answers

    What does the capital letter 'H' cast into the section indicate?

    <p>That the section is designed, manufactured, and inspected according to ASME BPVC Section IV</p> Signup and view all the answers

    What is a characteristic of the front and rear sections of cast iron boilers?

    <p>They have cleanout plugs on the side facing the outside of the boiler</p> Signup and view all the answers

    How do the hot gases travel through the horizontal sectional cast iron boilers?

    <p>In a zigzag pattern</p> Signup and view all the answers

    Why do multiple boilers increase the thermal efficiency of the boiler plant?

    <p>Because they allow most boilers to operate at full capacity during most of the heating season</p> Signup and view all the answers

    What is a disadvantage of using a single large boiler in a heating plant?

    <p>It operates at reduced load during most of the heating season</p> Signup and view all the answers

    What is the effect of cycling on the efficiency of a multiple boiler plant?

    <p>It reduces the overall efficiency of the plant by 2%</p> Signup and view all the answers

    What is the primary advantage of using multiple small boilers in a heating plant?

    <p>They improve the thermal efficiency of the boiler plant</p> Signup and view all the answers

    What is an advantage of multiple heating boiler plants compared to a single boiler plant of equal total capacity?

    <p>Should one boiler fail, the other boilers will be able to carry the full load except during extremely cold weather</p> Signup and view all the answers

    What is a characteristic of a modular heating boiler plant?

    <p>The water flow through all modules is continuous</p> Signup and view all the answers

    What is the purpose of a step controller in a multiple boiler plant?

    <p>To sense the outdoor air temperature and hot water supply temperature</p> Signup and view all the answers

    What is a key difference between high-pressure and low-pressure firetube boilers?

    <p>The design and code requirements</p> Signup and view all the answers

    Why are firetube boilers not suitable for use in high-pressure steam service?

    <p>They are not designed to handle high pressures</p> Signup and view all the answers

    What is a common feature of hot water firetube boilers?

    <p>They have an aquastat</p> Signup and view all the answers

    What is a characteristic of Scotch boilers?

    <p>They are available in small capacities</p> Signup and view all the answers

    What is a feature of Scotch boilers in hot water service?

    <p>They have a full-size hot water return and hot water supply connection</p> Signup and view all the answers

    What is a type of firebox boiler?

    <p>A low-pressure heating boiler</p> Signup and view all the answers

    What is the capacity range of firebox boilers?

    <p>150 kW to 7000 kW</p> Signup and view all the answers

    What is the main advantage of firebox boilers compared to Scotch-type firetube boilers?

    <p>They are more compact and can fit through standard doorways</p> Signup and view all the answers

    How do the hot gases travel in a vertical firetube boiler?

    <p>Upwards through the firetubes</p> Signup and view all the answers

    What is the purpose of the baffles in a vertical firetube boiler?

    <p>To slow the flue gas and maximize contact time</p> Signup and view all the answers

    What is the main difference between conventional hot water heating systems and in-floor radiant heat systems?

    <p>The size of the heat transfer surfaces</p> Signup and view all the answers

    What is the benefit of using a condensing boiler in in-floor radiant heat systems?

    <p>It increases the efficiency of the boiler to over 95%</p> Signup and view all the answers

    What is the function of the handholes in a firebox boiler?

    <p>To clean and inspect the waterside</p> Signup and view all the answers

    What is the purpose of the flue gas collector box in a vertical firetube boiler?

    <p>To collect the hot gases for venting</p> Signup and view all the answers

    Why are vertical firetube boilers less common in heating plants today?

    <p>They are not very efficient</p> Signup and view all the answers

    What is the advantage of a vertical firetube boiler when floor space is limited?

    <p>It requires less floor space</p> Signup and view all the answers

    What is the function of the circulating pump in a vertical firetube boiler?

    <p>To force the cooler water into the lower part of the boiler shell</p> Signup and view all the answers

    What is a characteristic shared by flexible tube and coil tube type watertube boilers in terms of their size and weight?

    <p>They are considerably smaller and lighter than firetube boilers of equal capacity.</p> Signup and view all the answers

    What is a requirement for the operation of flexible tube and coil tube type watertube boilers that is not necessary for firetube and cast iron sectional heating boilers?

    <p>Close monitoring of the water treatment.</p> Signup and view all the answers

    What is an advantage of cast iron sectional boilers compared to steel boilers?

    <p>They are more corrosion resistant.</p> Signup and view all the answers

    Why are flexible tube and coil tube type watertube boilers considered safer than firetube boilers?

    <p>They contain very little potential energy stored in their water.</p> Signup and view all the answers

    What is a feature of flexible tube and coil tube type watertube boilers that makes them suitable for smaller heating applications?

    <p>They come as packaged units, complete with firing equipment, automatic controls, and safety devices.</p> Signup and view all the answers

    What is an advantage of flexible tube and coil tube type watertube boilers in terms of their response to heating loads?

    <p>They respond rapidly to fluctuating heating loads.</p> Signup and view all the answers

    What is the primary reason why copper tubing is used in coil tube boilers?

    <p>It resists corrosion and has a better heat transfer rate</p> Signup and view all the answers

    What is the purpose of the fin-and-tube type heat exchanger in the upper section of the copper tubular heating boiler?

    <p>To increase the heating surface area</p> Signup and view all the answers

    What is the characteristic of the combustion chamber in a coil tube boiler?

    <p>It is surrounded by a tightly wound coil</p> Signup and view all the answers

    What is the purpose of the gaskets in a cast iron sectional boiler?

    <p>To seal the passageways between sections</p> Signup and view all the answers

    What is the advantage of using multiple coil tube boilers in a heating plant?

    <p>Flexibility to meet varying heating demands</p> Signup and view all the answers

    What is the primary difference between a vertical sectional cast iron boiler and a horizontal sectional cast iron boiler?

    <p>The arrangement of the sections</p> Signup and view all the answers

    What is the purpose of the collector hood in a cast iron sectional boiler?

    <p>To guide the hot gases to the draft hood</p> Signup and view all the answers

    What is the characteristic of the steam boiler varieties?

    <p>They use steel tubing</p> Signup and view all the answers

    What is the critical aspect of water treatment in coil tube boilers?

    <p>Preventing scale deposition</p> Signup and view all the answers

    What is the main advantage of using cast iron sectional boilers over installing more boilers?

    <p>They can be increased in capacity by installing more sections.</p> Signup and view all the answers

    Why are industrial type watertube boilers seldom selected for low-pressure heating plants?

    <p>All of the above</p> Signup and view all the answers

    What is the benefit of the compact design of the copper tubular heating boiler?

    <p>Reduced space requirements</p> Signup and view all the answers

    What is the function of the furnace walls in a bent tube watertube boiler?

    <p>To absorb radiant heat from the fire.</p> Signup and view all the answers

    What is the purpose of the outer membrane walls in a bent tube watertube boiler?

    <p>To form a passageway for the flue gases.</p> Signup and view all the answers

    What is the benefit of the bent tube watertube boiler design?

    <p>It is more compact and can fit through a standard doorway.</p> Signup and view all the answers

    How do the combustion gases travel in a bent tube watertube boiler?

    <p>Between the inner and outer membrane walls.</p> Signup and view all the answers

    What is the purpose of the circulating pump in a hot water application?

    <p>To force the water through the boiler.</p> Signup and view all the answers

    What is the advantage of the flexible watertube boiler design?

    <p>It allows the tube to expand and contract without creating excessive stress.</p> Signup and view all the answers

    What is the purpose of the insulated steel casing in a bent tube watertube boiler?

    <p>To enclose the boiler and reduce heat loss.</p> Signup and view all the answers

    What is the result of the combustion gases traveling between the inner and outer membrane walls in a bent tube watertube boiler?

    <p>They transfer heat to the walls by convection.</p> Signup and view all the answers

    What is the primary reason for designing cast iron boiler sections with extended surfaces?

    <p>To expose as large a surface as possible to the hot gases</p> Signup and view all the answers

    What is the advantage of specifying several small boilers in parallel, rather than a single large boiler, in a heating plant?

    <p>Increased efficiency during most of the heating season</p> Signup and view all the answers

    What is the purpose of the push nipple connections in a cast iron boiler section?

    <p>To connect the sections to each other</p> Signup and view all the answers

    What is the primary benefit of using multiple small boilers in a heating plant, compared to a single large boiler of equal total capacity?

    <p>Reduced risk of damage or injury due to smaller water capacity</p> Signup and view all the answers

    What is the significance of the capital letter 'H' cast into the top of a cast iron boiler section?

    <p>It indicates the section is designed, manufactured, and inspected according to ASME BPVC Section IV</p> Signup and view all the answers

    What is the main difference between high-pressure and low-pressure firetube boilers?

    <p>Design code, with high-pressure boilers designed to ASME BPVC Section I and low-pressure boilers designed to ASME BPVC Section IV</p> Signup and view all the answers

    What is the effect of cycling on the overall efficiency of a multiple boiler plant?

    <p>It decreases the overall efficiency of the plant, but only by a small amount</p> Signup and view all the answers

    What is the purpose of a step controller in a multiple boiler plant?

    <p>To sequence the startup and shutdown of boilers as load demand increases or decreases</p> Signup and view all the answers

    What is the primary advantage of horizontal sectional cast iron boilers?

    <p>They are more compact than vertical sectional boilers</p> Signup and view all the answers

    What is a characteristic of firebox boilers in hot water service?

    <p>They are designed to burn light fuel oil, natural gas, and propane</p> Signup and view all the answers

    What is the purpose of the cleanout plugs in the front and rear sections of a cast iron boiler?

    <p>To clean out debris from the boiler sections</p> Signup and view all the answers

    What is the primary reason for designing cast iron boiler sections with a zigzag pattern of gas passages?

    <p>To lengthen the time of contact between the hot gases and the heating surface</p> Signup and view all the answers

    What is the advantage of using multiple boilers in a heating plant, compared to a single large boiler of equal total capacity?

    <p>Increased reliability and reduced downtime</p> Signup and view all the answers

    What is the primary advantage of Scotch boilers in hot water service?

    <p>They have full-size hot water return and supply connections</p> Signup and view all the answers

    What is the primary advantage of using multiple small boilers in a heating plant, compared to a single large boiler?

    <p>Smaller boilers can be operated at maximum efficiency more often</p> Signup and view all the answers

    What is the effect of operating a single large boiler at reduced load on its efficiency?

    <p>It decreases the boiler's efficiency significantly</p> Signup and view all the answers

    What is the purpose of the isolation valves in Scotch boilers in hot water service?

    <p>To permit servicing or repairing the boiler without draining the entire heating system</p> Signup and view all the answers

    What is the advantage of a modular heating boiler plant?

    <p>It provides increased redundancy and reliability</p> Signup and view all the answers

    What is the primary benefit of using low-pressure boilers in a heating plant?

    <p>They reduce the risk of damage or injury due to lower water pressure</p> Signup and view all the answers

    What is the primary advantage of firetube boilers in hot water heating systems?

    <p>They are designed to operate at the lower temperatures required for hot water heating systems</p> Signup and view all the answers

    What is the primary advantage of firebox boilers over Scotch-type firetube boilers?

    <p>They are more compact and can fit through standard doorways</p> Signup and view all the answers

    What is the purpose of the baffles in a vertical firetube boiler?

    <p>To slow the flue gas and maximize contact time</p> Signup and view all the answers

    Why are vertical firetube boilers less common in heating plants today?

    <p>They are less efficient than other boiler designs</p> Signup and view all the answers

    What is the benefit of using a condensing boiler in in-floor radiant heat systems?

    <p>It allows for efficiencies of over 95%</p> Signup and view all the answers

    What is the purpose of the handholes in a firebox boiler?

    <p>To clean the waterside</p> Signup and view all the answers

    What is a characteristic of the hot water return and hot water supply connections in firebox boilers?

    <p>They are equipped with isolation valves</p> Signup and view all the answers

    How do the hot gases travel in a vertical firetube boiler?

    <p>They travel upwards through the flue gas collector box</p> Signup and view all the answers

    What is the primary advantage of using multiple small boilers in a heating plant?

    <p>It provides more flexibility in response to heating loads</p> Signup and view all the answers

    What is the purpose of the manhole in a firebox boiler?

    <p>To clean and inspect the boiler</p> Signup and view all the answers

    What is the main difference between conventional hot water heating systems and in-floor radiant heat systems?

    <p>The size of the heating surface area</p> Signup and view all the answers

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