3e151 B Set Vol 2
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Whose instructions must you follow when you inspect gas-fired heaters?
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Air force bulletins
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Air force procedures
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Manufacturers' instructions
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Local procedures and air force bulletins
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About This Quiz
This quiz titled '3E151 B Set Vol 2' assesses knowledge on furnace operations, focusing on components like heat exchangers, bearings, and controls in forced-warm air furnaces. It is designed for individuals pursuing professional certification in HVAC systems.
Quiz Preview
- 2.
The most important inspection you perform on a gas-fired furnace is one for
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Power
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Unit size
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A gas leak
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Unit location
Correct Answer
A. A gas leakExplanation
The most important inspection to perform on a gas-fired furnace is for a gas leak. This is crucial because a gas leak can be extremely dangerous, leading to potential explosions or carbon monoxide poisoning. Detecting and fixing a gas leak ensures the safety of the occupants and prevents any potential hazards.Rate this question:
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- 3.
The inside part of the a heat exchanger in a forced-warm air furnace is known as the
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Burner cone
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Draft chamber
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Casing chamber
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Combustion chamber
Correct Answer
A. Combustion chamberExplanation
The inside part of a heat exchanger in a forced-warm air furnace is known as the combustion chamber. This is where the fuel and air mix and ignite to produce heat. The combustion chamber is designed to efficiently burn the fuel and transfer the heat to the surrounding air. It is an essential component of the furnace as it is responsible for generating the heat that is then distributed throughout the building. The burner cone, draft chamber, and casing chamber are not the correct terms for the inside part of a heat exchanger in a forced-warm air furnace.Rate this question:
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- 4.
What is the most serious defect to look for when you inspet a heat exchanger?
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Warped metal
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Soot deposits
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Blockages
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Cracks
Correct Answer
A. CracksExplanation
When inspecting a heat exchanger, the most serious defect to look for is cracks. Cracks in a heat exchanger can lead to leakage of fluids or gases, which can result in reduced efficiency or even complete failure of the system. Cracks can also pose safety hazards, such as the risk of fire or explosion. Therefore, identifying and addressing cracks in a heat exchanger is crucial to ensure its proper functioning and prevent any potential damage or accidents.Rate this question:
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- 5.
Water-gauge glasses are used to indicate the
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Color of the boiler water
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Boiler operating pressure
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Water level of the boiler
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Amount of fluctuation in the boiler
Correct Answer
A. Water level of the boilerExplanation
Water-gauge glasses are transparent tubes that are attached to a boiler to indicate the water level inside it. The water level in a boiler needs to be monitored to ensure safe and efficient operation. By observing the water-gauge glass, operators can determine if the water level is too low or too high, which can help prevent damage to the boiler and maintain proper steam production. Therefore, the correct answer is that water-gauge glasses are used to indicate the water level of the boiler.Rate this question:
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- 6.
Using text figure 3-2, answer the following question. Slugs of water carried at high velocity with steam in steamlines can cause
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Pressure failure in low-pressure systems
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Heating units to fail to heat
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A cast-iron boiler to break
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Water hammer
Correct Answer
A. Water hammerExplanation
Water hammer is the correct answer. Water hammer refers to the sudden increase in pressure that occurs when a slug of water traveling at high velocity in a steamline comes to a sudden stop. This can cause damage to the system, including pipe ruptures, valve failures, and equipment damage.Rate this question:
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- 7.
What valve do you close when starting up a boiler?
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Gauge glass valves
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All blowdown valves
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Vents on boiler drum
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Feedwater stop check valves
Correct Answer
A. All blowdown valvesExplanation
When starting up a boiler, it is necessary to close all blowdown valves. Blowdown valves are used to remove impurities and sediment from the boiler, ensuring its efficient operation. By closing these valves during startup, it prevents any unwanted discharge of water or steam from the boiler, allowing it to build up pressure and reach the desired operating conditions. Closing the blowdown valves also helps in maintaining the water level and preventing any loss of valuable water or steam during the startup process.Rate this question:
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- 8.
One method of boiler layup is dry storage; the other method is
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Dry chemical storage
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Dry vapor storage
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Wet vapor storage
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Wet storage
Correct Answer
A. Wet storageExplanation
Wet storage is the other method of boiler layup besides dry storage. Wet storage involves filling the boiler with water and maintaining it at a specific water level to prevent corrosion and maintain the integrity of the boiler during periods of inactivity. This method is commonly used when the boiler will be out of service for an extended period of time. It helps to prevent the formation of rust and scale, ensuring that the boiler remains in good condition and ready for use when needed.Rate this question:
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- 9.
Three common types of bearing used on warm-air furnace assemblies
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Anti-friction, sleeve, and bronze
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Sleeve, thrust, and anti-friction
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Plain, thrust, and anti-friction
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Thrust, plain, and bronze
Correct Answer
A. Sleeve, thrust, and anti-frictionExplanation
The correct answer is sleeve, thrust, and anti-friction. These are the three common types of bearings used on warm-air furnace assemblies. A sleeve bearing is a type of plain bearing that consists of a cylindrical sleeve that supports the rotating shaft. A thrust bearing is designed to handle axial loads and is used to prevent axial movement of the shaft. Anti-friction bearings, also known as rolling element bearings, reduce friction by using rolling elements such as balls or rollers between the stationary and rotating parts.Rate this question:
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- 10.
Gas burners primary controls operate in response to signals received from
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Relays
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Switches
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Thermostats
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A heating element
Correct Answer
A. ThermostatsExplanation
Gas burners primary controls operate in response to signals received from thermostats. Thermostats are devices that sense the temperature in the surrounding environment and send signals to the primary controls of the gas burner to adjust the flame accordingly. This allows the gas burner to maintain a desired temperature by turning on or off the gas supply based on the thermostat's signals. Switches and relays may be used in the overall control system, but the primary control and regulation of the gas burner is achieved through the use of thermostats.Rate this question:
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- 11.
Which type of space heater control valve has an infinite number of fuel firing rates between high fire and low fire?
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Step-modulating
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Single-stage
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Two-stage
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Manual
Correct Answer
A. Step-modulatingExplanation
A step-modulating space heater control valve has an infinite number of fuel firing rates between high fire and low fire. This means that it can adjust the fuel flow in small increments, allowing for precise control of the heating output. Unlike single-stage or two-stage valves, which have fixed firing rates, a step-modulating valve offers more flexibility and efficiency in regulating the heat output of the space heater. A manual valve, on the other hand, requires manual adjustment and does not provide the same level of control as a step-modulating valve.Rate this question:
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- 12.
The internal feedline is installed in the water space near, but not touching, the
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Downcomer tubes
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Side of the drum
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Bottom of the drum
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Surface blowdown line
Correct Answer
A. Bottom of the drumExplanation
The internal feedline is installed at the bottom of the drum. This location allows for efficient transfer of water from the drum to the downcomer tubes, which are located near the side of the drum. Placing the feedline at the bottom ensures that it is submerged in the water, allowing for a continuous flow of water to the downcomer tubes. Additionally, this location helps prevent any interference with the surface blowdown line, which is typically located at the top of the drum.Rate this question:
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- 13.
Water columns are contructed of
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Aluminum
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Pig iron
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Cast iron
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Stainless steel
Correct Answer
A. Cast ironExplanation
Cast iron is a suitable material for constructing water columns because it is known for its durability and strength. It can withstand high pressure and is resistant to corrosion, making it ideal for use in water systems. Cast iron also has good heat retention properties, which can be beneficial in regulating the temperature of the water. Additionally, cast iron is relatively inexpensive compared to other materials like stainless steel, making it a cost-effective choice for constructing water columns.Rate this question:
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- 14.
What do you use to prevent safety valves from lifting during a hydrostatic test?
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Refractory cement
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Lock-tight
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Gags
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Rope
Correct Answer
A. GagsExplanation
Gags are used to prevent safety valves from lifting during a hydrostatic test. Gags are mechanical devices that are inserted into the valve to hold it in a closed position. They are designed to provide a temporary blockage and prevent the valve from opening under the pressure of the test. This ensures that the valve remains closed and the test can be conducted safely without any leakage or release of pressure.Rate this question:
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- 15.
The pressure relief valve for a water boiler must be
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Heat operated
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Spring operated
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Gravity operated
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Electrically operated
Correct Answer
A. Spring operatedExplanation
A pressure relief valve for a water boiler must be spring operated because it needs to automatically release excess pressure when it reaches a certain level. A spring-operated valve is designed to open when the pressure inside the boiler exceeds a predetermined limit, allowing the excess pressure to escape and preventing potential damage or explosion. This type of valve is reliable and does not require external power or control, making it suitable for ensuring the safety of the boiler system.Rate this question:
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- 16.
What is the most common type of glycol used in hot-water heating systems?
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Triethylene
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Biethylene
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Propylene
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Ethylene
Correct Answer
A. EthyleneExplanation
Ethylene glycol is the most common type of glycol used in hot-water heating systems. It is a colorless and odorless liquid that has excellent heat transfer properties. Ethylene glycol is used as an antifreeze agent in these systems to prevent freezing and to protect against corrosion. It has a high boiling point and low freezing point, making it suitable for use in hot-water heating systems.Rate this question:
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- 17.
If the boiler feed pump will not deliver the correct pressure for a hydrostatic test, use
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Another feed pump
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A steam injector
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Two feed pumps
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A hand pump
Correct Answer
A. A hand pumpExplanation
If the boiler feed pump is unable to deliver the correct pressure for a hydrostatic test, using a hand pump can be an alternative solution. A hand pump is manually operated and does not rely on the functioning of the boiler feed pump. It can be used to generate the necessary pressure for the test, ensuring that it is conducted accurately and safely.Rate this question:
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- 18.
What type of warm-air furnace is known as a high-boy furnace?
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Horizontal
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Downflow
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Gravity
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Upflow
Correct Answer
A. UpflowExplanation
An upflow warm-air furnace is known as a high-boy furnace because it is designed to be installed in an upright position, with the air intake at the bottom and the warm air discharge at the top. This configuration allows for efficient heating as the warm air rises and circulates throughout the room. The term "high-boy" refers to the furnace's taller and more slender profile compared to other types of warm-air furnaces.Rate this question:
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- 19.
Infrared heaters are not used in an area that contains ignitable dust, gases, or vapors in hazardous concentrations because of
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Their very low surface temperature
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Their high surface temperature
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The porosity of their ceramic elements
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The possibility of corrosion damage to the elements
Correct Answer
A. Their high surface temperatureExplanation
Infrared heaters are not used in areas with ignitable dust, gases, or vapors in hazardous concentrations because of their high surface temperature. This is because the high surface temperature of the heater can potentially ignite or cause explosions when it comes into contact with these hazardous substances. Therefore, it is safer to use other heating methods in such environments to prevent any potential accidents or hazards.Rate this question:
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- 20.
While troubleshooting a warm-air heating system, you notice the flame burning in a long, yellow-tipped manner? What would cause this to happen?
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A strong updraft
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A very weak cross draft
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Low voltage in the control circuit
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Insufficient primary combustion
Correct Answer
A. Insufficient primary combustionExplanation
The flame burning in a long, yellow-tipped manner is indicative of insufficient primary combustion. This means that the fuel-air mixture is not being properly ignited, resulting in an incomplete combustion process. This could be caused by factors such as a clogged or dirty burner, inadequate air supply, or improper fuel delivery. Insufficient primary combustion can lead to reduced heating efficiency, increased fuel consumption, and potentially the release of harmful gases.Rate this question:
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- 21.
In an 8-hour shift, how many times should you blow down a steam boiler?
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Four
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Three
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Two
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One
Correct Answer
A. OneExplanation
In an 8-hour shift, you should blow down a steam boiler only once. Blowing down a steam boiler refers to the process of removing sediment and impurities from the boiler water. This is done to maintain the efficiency and safety of the boiler. Blowing down the boiler once during an 8-hour shift ensures that any buildup of sediment or impurities is removed, preventing potential issues with the boiler's performance.Rate this question:
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- 22.
Two steam-stop valves are required when two or more boilers are connected to a common steam line to
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Increase efficiency
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Regulate the steam flow
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Allow warm-up steam into a cold boiler
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Prevent steam from entering an idle boiler
Correct Answer
A. Prevent steam from entering an idle boilerExplanation
When two or more boilers are connected to a common steam line, having two steam-stop valves is necessary to prevent steam from entering an idle boiler. This is important because if steam were to enter an idle boiler, it could cause damage or lead to inefficiency in the system. By having two valves, one can be closed while the other remains open, ensuring that steam only flows into the active boilers and not into the idle ones.Rate this question:
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- 23.
Which fan drive is used if no electrical power is availiable?
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Centrifugal
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Reciprocating
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Steam turbine
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Electrical turbine
Correct Answer
A. Steam turbineExplanation
A steam turbine is used when no electrical power is available. Steam turbines are driven by high-pressure steam generated by boilers, and they convert the thermal energy of the steam into mechanical energy to drive a fan or any other equipment. Since no electrical power is available, a steam turbine is a suitable option as it can operate independently without relying on external power sources.Rate this question:
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- 24.
What would cause a priming and foaming condtion in a steaming boiler?
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A low water level
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Low steam demand
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Low solids concentration
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High solids concentration
Correct Answer
A. High solids concentrationExplanation
A high solids concentration in a steaming boiler can cause a priming and foaming condition. When there is a high concentration of solids, such as dissolved minerals or impurities, in the boiler water, it can lead to the formation of foam or froth. This foam can interfere with the normal operation of the boiler, causing priming, which is the carryover of water droplets along with the steam. This can result in reduced efficiency, increased corrosion, and potential damage to the boiler and other equipment. Therefore, it is essential to maintain proper water treatment and control the solids concentration in the boiler to prevent this issue.Rate this question:
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- 25.
The purpose of a continuous blowdown system is to maintain the concentration of the boiler water at the proper limits and remove
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Chemicals from the boiler
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Foreign soilds from the boiler water
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Sludge from the bottom of the boiler
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Calcium from the bottom of the boiler
Correct Answer
A. Foreign soilds from the boiler waterExplanation
A continuous blowdown system is designed to maintain the concentration of the boiler water within the appropriate limits. One of its main functions is to remove foreign solids from the boiler water. These foreign solids can include impurities, such as dirt, rust, and other contaminants that may accumulate in the boiler system. By removing these foreign solids, the blowdown system helps to prevent potential blockages, corrosion, and other issues that can arise from the presence of these impurities in the boiler water.Rate this question:
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- 26.
What do you use to remove soot, dirt, and scale from flues and fireboxes of boilers?
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Chemicals
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Wire brushes
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Putty knives
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Soap and water
Correct Answer
A. Wire brushesExplanation
Wire brushes are used to remove soot, dirt, and scale from flues and fireboxes of boilers because they have stiff bristles that can effectively scrub away the buildup. Chemicals may be used in conjunction with wire brushes, but they are not the primary tool for removing these substances. Putty knives are not suitable for this task as they may damage the surfaces of the flues and fireboxes. Soap and water alone are not sufficient for removing stubborn soot, dirt, and scale.Rate this question:
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- 27.
Flat surfaces of a boiler are held in place by braces, which are called
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Baffles
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Tubes
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Stays
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Drums
Correct Answer
A. StaysExplanation
The correct answer is "stays." In a boiler, the flat surfaces are held in place by braces called stays. Stays are structural components that provide support and prevent movement or deformation of the flat surfaces. They help maintain the integrity and stability of the boiler structure, ensuring that the flat surfaces remain securely in place during operation.Rate this question:
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- 28.
A smoke detection system sensor is
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A protection relay
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An infrared sensor
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A lead sulfide sensor
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A cadmium sulfide photocell
Correct Answer
A. A cadmium sulfide photocellExplanation
A smoke detection system sensor is a cadmium sulfide photocell. This type of sensor is commonly used in smoke detectors to detect the presence of smoke particles in the air. When smoke enters the detector, it scatters light onto the photocell, causing a decrease in the photocell's resistance. This change in resistance is then detected by the smoke detection system, triggering an alarm to alert occupants of a potential fire.Rate this question:
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- 29.
The two methods of cleaning the waterside of boiler tubes are
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Mechanical and air pressure
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Mechanical and electrical
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Chemical and electrical
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Mechanical and chemical
Correct Answer
A. Mechanical and chemicalExplanation
The correct answer is mechanical and chemical. Mechanical cleaning involves physically removing deposits and debris from the waterside of boiler tubes using tools such as brushes, scrapers, or water jets. Chemical cleaning, on the other hand, involves using chemicals or cleaning agents to dissolve or loosen deposits and then flushing them out. Both methods are commonly used in combination to effectively clean the waterside of boiler tubes.Rate this question:
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- 30.
Scale deposits in a boiler are excessive when they
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Weaken joints and corners
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Decrease water pressure
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Interfere with heat transfer and impede water flow
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Cause sludge to form and water temperature to increase
Correct Answer
A. Interfere with heat transfer and impede water flowExplanation
When scale deposits in a boiler interfere with heat transfer, it means that the heat produced by the boiler is not efficiently transferred to the water. This can lead to decreased efficiency and increased energy consumption. Additionally, when scale deposits impede water flow, it can result in reduced water circulation within the boiler, leading to uneven heating and potential overheating in certain areas. Therefore, excessive scale deposits can have a negative impact on the overall performance and functionality of the boiler.Rate this question:
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- 31.
Hot-water system layup is usually done
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Monthly
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Semiannually
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After initial startup
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After seasonal overhaul is completed
Correct Answer
A. After seasonal overhaul is completedExplanation
After seasonal overhaul is completed, hot-water system layup is usually done. This means that the hot-water system is shut down and prepared for a period of inactivity, typically during the off-season or when it is not needed. Seasonal overhaul refers to the maintenance and inspection activities carried out on the system before it is put back into operation. By performing the layup after the seasonal overhaul, any necessary repairs or adjustments can be made, ensuring that the system is in optimal condition before it is shut down.Rate this question:
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- 32.
When the tempetature in a gas-fired furnance becomes excessive, what unit stops the burner?
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Delayed-action control
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Starting control
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Ignition control
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Limit control
Correct Answer
A. Limit controlExplanation
The limit control unit is responsible for stopping the burner in a gas-fired furnace when the temperature becomes excessive. This unit acts as a safety mechanism to prevent overheating and potential damage to the furnace or surrounding areas. It monitors the temperature and when it reaches a predetermined limit, it sends a signal to shut off the burner, ensuring that the temperature remains within a safe range.Rate this question:
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- 33.
What type of gas space heaters can be gravity or mechanical air-circulation type and vented or unvented type?
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Ceiling
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Floor
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Room
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Wall
Correct Answer
A. RoomExplanation
Gas space heaters can be of different types based on the way they circulate air and whether they are vented or unvented. The options provided in the question, such as ceiling, floor, and wall, refer to the physical location of the heaters. However, the correct answer, "room," refers to the type of gas space heaters that can be both gravity or mechanical air-circulation type and vented or unvented. In other words, gas space heaters designed for rooms can have different air-circulation mechanisms and venting options.Rate this question:
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- 34.
Which space heater must be used inly in a well-ventilated rooms?
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Wall
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Room
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Vented
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Unvented
Correct Answer
A. UnventedExplanation
An unvented space heater must be used only in well-ventilated rooms because it does not have an exhaust or vent to remove the combustion byproducts, such as carbon monoxide, outside. Without proper ventilation, these byproducts can accumulate in the room and pose a serious health risk to the occupants. Therefore, it is important to use an unvented space heater only in a well-ventilated area to ensure the safety and well-being of everyone in the room.Rate this question:
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- 35.
What keeps a safety valve closed against the force developed by the steam pressure acting under the valve disc?
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A compressed bellows
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A compressed spring
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A compressed nut
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A bellows
Correct Answer
A. A compressed springExplanation
A compressed spring keeps a safety valve closed against the force developed by the steam pressure acting under the valve disc. When the steam pressure exceeds a certain level, the force exerted by the compressed spring is overcome, causing the safety valve to open and release the excess pressure. The compressed spring acts as a mechanical mechanism to maintain the valve in a closed position until the pressure reaches a critical point.Rate this question:
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- 36.
Which mechanical draft system is the most flexible?
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Natural
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Induced
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Forced
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Balanced
Correct Answer
A. BalancedExplanation
A balanced mechanical draft system is the most flexible because it combines the features of both induced and forced draft systems. It uses a combination of fans to create a balanced air pressure within the system, allowing for more control over the airflow. This flexibility is important in various industrial applications where the airflow needs to be adjusted based on different operating conditions.Rate this question:
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- 37.
A compound Bourdon gauge can measure
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Pressure and temperature
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Vacuum and level
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Pressure and vacuum
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Temperature and level
Correct Answer
A. Pressure and vacuumExplanation
A compound Bourdon gauge is a type of pressure gauge that is capable of measuring both pressure and vacuum. This is achieved by using two separate Bourdon tubes, one for measuring pressure and the other for measuring vacuum. The pressure tube is designed to expand under pressure, while the vacuum tube is designed to contract under vacuum. By combining the readings from both tubes, the gauge can accurately measure both positive and negative pressure values, making it suitable for applications where pressure and vacuum measurements are required.Rate this question:
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- 38.
If a complete failure of ignition occurs, purge setting for
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20 mins
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15 mins
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10 mins
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5 mins
Correct Answer
A. 5 minsExplanation
If a complete failure of ignition occurs, the purge setting should be set for 5 minutes. This means that the system will purge the fuel-air mixture for 5 minutes before attempting to ignite it again. This is done to ensure that any accumulated fuel or gas is cleared from the system before another ignition attempt is made. A shorter purge setting may not be enough time to fully clear the system, while a longer purge setting may unnecessarily delay the ignition process. Therefore, a 5-minute purge setting strikes a balance between ensuring safety and efficiency.Rate this question:
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- 39.
Low-water protection is accomplished by
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Thermocouples
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Microswitches
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Float-type cutoffs
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Pressure-regulating valves
Correct Answer
A. Float-type cutoffsExplanation
Float-type cutoffs are used to accomplish low-water protection. These devices are designed to detect the water level in a system and automatically shut off the flow of water if it falls below a certain level. They work by utilizing a float mechanism that rises and falls with the water level. When the water level drops too low, the float triggers a switch that shuts off the water supply, preventing damage to the system. This mechanism is commonly used in boilers and other water-based systems to ensure that the water level remains at a safe and functional level.Rate this question:
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- 40.
What surrounds the tubes of water-tube boiler?
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Hot gases
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Hot air
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Water
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Steam
Correct Answer
A. Hot gasesExplanation
The tubes of a water-tube boiler are surrounded by hot gases. In a water-tube boiler, the water flows through the tubes while the hot gases produced by burning fuel surround the tubes. This design allows for efficient heat transfer from the hot gases to the water, resulting in the generation of steam. Hot air, water, and steam are not the correct answers as they do not directly surround the tubes in a water-tube boiler.Rate this question:
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- 41.
An increase in pressure and the surface of water will
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Increase the boiling point
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Decrease the boiling point
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Increase the molecular count
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Decrease the molecular count
Correct Answer
A. Increase the boiling pointExplanation
When pressure is increased, the boiling point of water also increases. This is because an increase in pressure compresses the water molecules, making it harder for them to escape into the gas phase. As a result, more heat is required to break the intermolecular forces and convert water into vapor. Therefore, an increase in pressure raises the boiling point of water.Rate this question:
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- 42.
At least how many means of feeding water must all boilers with 500 square feet or more of water heating surface have?
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One
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Two
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Three
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Four
Correct Answer
A. TwoExplanation
Boilers with 500 square feet or more of water heating surface must have at least two means of feeding water. This is necessary to ensure a reliable and continuous water supply to the boiler for efficient operation and to prevent any potential damage or failure. Having multiple means of feeding water also provides redundancy in case one system fails or requires maintenance, allowing the boiler to continue functioning without interruption.Rate this question:
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- 43.
What are the two types of low-water cutoffs used on steam boilers?
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Float and switch
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Float and probe
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Lever and switch
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Lever and probe
Correct Answer
A. Float and probeExplanation
The correct answer is float and probe. Float and probe are the two types of low-water cutoffs used on steam boilers. A float type low-water cutoff operates by using a float to detect the water level in the boiler and shut off the burner if the water level drops too low. A probe type low-water cutoff uses a probe to directly sense the water level in the boiler and shut off the burner if the water level falls below a certain point. These cutoffs are important safety devices to prevent damage to the boiler and ensure proper operation.Rate this question:
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- 44.
Which adjustment provides a choice of firing rate at burner startup?
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ON/OFF
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GAIN/LOSS
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UNISON/SEQUENCE
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ADDITIVE/SUBTRACTIVE
Correct Answer
A. UNISON/SEQUENCEExplanation
The adjustment that provides a choice of firing rate at burner startup is UNISON/SEQUENCE. This adjustment allows the user to select between the two options, allowing for flexibility in controlling the firing rate during startup.Rate this question:
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- 45.
The purpose of closing and tagging all valves and drains of a boiler before entering it for an inspection is to
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Prevent steam and water from entering the unit
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Keep various contaminates from entering the boiler
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Prevent the atmosphere from causing corrosion to the boiler metals
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Prevent sludge and mud from leaving the boiler, thus ensuring a valid inspection
Correct Answer
A. Prevent steam and water from entering the unitExplanation
Closing and tagging all valves and drains of a boiler before entering it for an inspection is done to prevent steam and water from entering the unit. This is important because entering a boiler while it is still pressurized or contains water can be extremely dangerous. By closing and tagging all valves and drains, it ensures that no steam or water can enter the unit while the inspection is being conducted, thereby ensuring the safety of the person entering the boiler.Rate this question:
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- 46.
The device that automatically supplies water to a hot-water boiler is the
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Inlet gauge
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Globe valve
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Ball-cock valve
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Pressure-regulating valve
Correct Answer
A. Pressure-regulating valveExplanation
A pressure-regulating valve is the device that automatically supplies water to a hot-water boiler. This valve is responsible for maintaining a consistent and safe pressure level within the boiler by regulating the flow of water. It ensures that the boiler is supplied with the appropriate amount of water to maintain optimal functioning and prevent any damage or accidents that may occur due to excessive pressure.Rate this question:
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- 47.
What method of heat transfer is used when floors or other objects reradiate to the air?
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Conduction
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Convection
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Radiation
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Absorption
Correct Answer
A. ConvectionExplanation
When floors or other objects reradiate heat to the air, the method of heat transfer being used is convection. Convection is the process by which heat is transferred through the movement of fluids, such as air or water. In this case, the heat from the floors or objects is transferred to the surrounding air through convection, as the air near the objects gets heated and rises, creating a convection current that spreads the heat throughout the room.Rate this question:
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- 48.
Water hammer in a piping sysytem is prevented by using
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Open traps
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Flash tanks
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Saturated pressure
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Pressure release valves
Correct Answer
A. Flash tanksExplanation
Water hammer in a piping system is a phenomenon that occurs when there is a sudden change in the flow velocity of water, resulting in pressure surges and vibrations. Flash tanks are used to prevent water hammer by providing a space for the sudden increase in pressure to be absorbed. When there is a surge in pressure, the flash tank allows the excess water and steam to be released, preventing the pressure from damaging the piping system. Open traps, saturated pressure, and pressure release valves do not specifically address the issue of water hammer prevention.Rate this question:
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- 49.
A steam-stop valve must be of the outside screw-and-yoke, rising-stem typewhenever it is
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2 inches or less
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2 inches or larger
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The only valve used
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Used with a nonreturn valve
Correct Answer
A. 2 inches or largerExplanation
A steam-stop valve must be of the outside screw-and-yoke, rising-stem type whenever it is 2 inches or larger. This means that for steam-stop valves that are 2 inches or larger in size, they should have an outside screw-and-yoke mechanism with a rising stem. This type of valve design allows for better control and regulation of steam flow in larger systems.Rate this question:
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Mar 21, 2023Quiz Edited by
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Mar 04, 2012Quiz Created by
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