Washington DC 3rd Class Boiler Practice Test

These questions are part of the practice quiz. Start practicing

• What do you call a reading from the center of an impeller across to the gauge?
• In a refrigeration cycle, which component condenses vapor into a liquid?
• Air leaking into the inner and outer of the boiler, what will happen?
• A cadmium sulfide photocell senses which form of light?
• Where is the total hardness of a softener reading 0.5 grains? (Using the conversion 17.1 × 0.5 = 8.6)
• Which byproduct fuel has the lowest heating value?
• What is the maximum range of pressure settings for all the saturated steam safety valves on boilers relative to the highest set valve?
• The toxicity limit for Class B refrigerants is given in which unit?
• What does RTD stand for in temperature sensing?
• In boiler terminology, what is the difference between the theoretical pump displacement and the actual displacement called?
• Where is high temperature vapor found?
• Proximate analysis identifies four data points: volatile matter, moisture, fixed carbon, and ash. Which option lists these four components correctly?
• What is the circumference of a circle with a 10 inch diameter?
• What type of valve would not be a good choice if sediment is present in a system?
• If the highest set valve is 150 psi, what would be the maximum range for all saturated steam safety valves?
• How many BTUs does it take to raise 10 lb of water from 40°F to 41°F?
• To protect boiler refractory from excess heat and increase boiler capacity, which addition is used?
• Which jumper is used to connect the neutral and ground?
• With hydroxide present and normal oxygen levels, which chemical will cause problems?
• Which gas is inert in combustion and not a heat-producing component?
• Controls which use a quantity measured over a range of dynamic values are?
• How many BTUs are required to raise 10 pounds of steam from 40°F to 41°F?
• What is a condenser?
• The color for an R-134A refrigerant cylinder is _______?
• Which of the following is a positive displacement pump?
• Cadmium sulfide photocells are most responsive to which spectrum?
• What is the volume of a cylindrical tank that has a 24 inch diameter and a 48 inch length?
• Which chemical compounds in water cause permanent hardness?
• What is the relief pressure (psi) for a 3-inch pressure relief valve with a 1500-pound spring?
• Convert 31°C to Fahrenheit.
• If boiler water has a pH of 5, what class of chemicals is added to neutralize the acidity?
• Where is the Adamson Ring joint commonly located?
• Why is platinum used in RTD (Resistive Temperature Device)?
• Which unit is commonly used to express the toxicity of a Class B refrigerant?
• What is the area of a circle with a 35 inch diameter?
• What is the likely cause of high excess in a condensate return tank with temperature up to 20 degrees above normal?
• Which statement describes the Adamson Ring in relation to furnaces?
• Where is medium temperature liquid found?
• Which valve is typically used to control blow down to avoid rapid flow changes?
• What is the maximum pressure that a 12 x 5 x 15 duplex reciprocating pump can develop when operated with 75-psi steam?
• What is meant by the percent of skip, step, and slip in a pump?
• A duplex reciprocating pump has a bore of 10 inches, a stroke of 6 inches, runs at 120 rpm, and slip of 4%. What is the approximate capacity in gallons per minute?
• In a hydrostatic test, to what multiple of MAWP is the pressure raised?
• A column of water 150 feet tall in a vertical pipe will produce what pressure at the bottom in psi?
• What is the replacement refrigerant for R-22 in modern systems?
• In an open type expansion tank, how high above the highest heating element should the tank be mounted?
• In a refrigeration cycle, which component expands high-pressure liquid to low-pressure liquid?
• What is the flow rate, in gallons per minute, of water flowing through an 8 ft diameter pipe at a velocity of 7 ft/s?
• In the pump horsepower formula HP = GPM × 8.33 × Height ÷ (33000 × Efficiency), what constant is multiplied by GPM and Height?
• Which formula expresses the area of a circle in terms of its diameter?
• What are the four steps of Zeolite Rejuvenation in order?
• With normal oxygen and low alkalinity, what is added to boiler water?
• Where should the expansion tank on a closed-loop system be located?
• What is the area of a circle with a diameter of 18 inches using A = D^2 x 0.7854?
• What type of maintenance is practiced when equipment is allowed to run until it fails?
• What is the area of a circle with a 10 inch diameter?
• Which description best explains a foot valve on a pump?
• What is recommended as the best electrical grounding method?
• In the expansion tank sizing problem, what was the system water temperature used for calculation?
• Who may reuse recycled and filtered refrigerant?
• What is the normal sodium sulfite range used in boilers?
• What refrigerant has replaced R-22 in many HVAC systems?
• Discrete control when used for steam pressure is what type of control?
• Which term best describes a control system that switches devices on or off as a single measured variable crosses a threshold?
• The component that removes moisture from a refrigeration system is the
• How is the fire tube in a boiler secured?
• The safety valve lever test should be performed when boiler pressure reaches what fraction of the operating pressure?
• Convert 92°C to Fahrenheit.
• Which of the following methods are used to support large furnaces in a SM boiler?
• When conducting an evaporation test, the operator must secure what?
• Who can make adjustments or repairs on a safety valve?
• Where is the cooling tower bleed line located?
• Which treatment is used to combat scale?
• In the expansion formula Exp in = (T1 - T2) x L x 0.0000065, what does the constant 0.0000065 represent?
• Which device is used to remove moisture from refrigerant lines?
• Which of the following is not a parameter sensed by a three-element feed regulator?
• Which component is the heart of a refrigeration system?
• Which term describes an AHU that uses separate coils in side-by-side ducts for cooling and heating?
• The heart of a refrigeration system is the _______
• In a duct air handling system, space thermostat control building temperatures by?
• Data printed on the equipment nameplate typically includes manufacturer, model, serial number, and what?
• A replacement refrigerant for R-12 medium and high temperature refrigeration application is _____?
• What is the total force acting on a 4.5 inch pressure relief valve with a popping pressure of 500 psi?
• What is the volume in cubic inches of a cylinder with a 15 inch diameter and 30 inch height?
• A boiler rated at 96,250 lb/h corresponds to approximately how many boiler horsepower?
• In the compression ratio example, why is 14.7 psi added to both head and suction pressures before division?
• A 12 inch pipe filled with water to a height of 250 feet will have what pressure at the bottom of the pipe?
• A duplex reciprocating pump has a bore of 8 inches, a stroke of 20 inches, runs at 200 rpm, and slip of 5%. What is the pump capacity in gpm?
• What must be submitted to the code official when field assembly of boilers is required?
• In a siphon between a boiler and pressure controls, what is the water seal called?
• Boiler safety controls protect against how many distinct conditions?
• Approximately how many gallons per month of chemical solution are required in the example?
• Which chemical pairing is used to combat corrosion in boiler water systems?
• Which component in the refrigeration cycle reduces high pressure gas to a liquid by removing heat?
• How is moisture removed from a refrigerant system?
• A _____ valve should be used for throttling purposes?
• A proximate analysis of coal will not report what?
• What is the name of the hanged joint between two or more furnaces that may be located in the center of the furnace and spaced no more than 18 inches apart?
• A foot valve is described as which of the following?
• The energy unit used to express the heat required to raise water by one degree Fahrenheit per pound is known as what?
• Between which two components does a siphon provide a protective water seal for boiler instrumentation?
• During a 24-hour operation, how often should you check the water level?
• If a boiler is operating at 80% load and the flame goes out suddenly, what happens to the water?
• What is the maximum toxicity level, in parts per million, for a Class B refrigerant?
• In the horsepower calculation, increasing efficiency while holding GPM and height constant will do what to the calculated horsepower?
• What type of flame detector senses infrared light?
• How many cubic inches are in a gallon?
• Which statement is NOT an advantage of the economic type boiler over the conventional type boiler?
• The flow area A used in the relief valve calculation for a 2.5-inch valve is approximately:
• A duplex reciprocating pump has a bore of 5 inches, a stroke of 12 inches, runs at 75 rpm, and has a slip of 7%. What is the pump capacity in gallons per minute (gpm)?
• What is the monthly chemical cost calculated in the example?
• Which pump requires more horsepower based on the given calculations?
• An air handler unit that provides heating, cooling, ventilation, and air conditioning to more than one building or area and has its cooling & heating Coil in separate side-by side ducts is called a _______air handling unit?
• In a dual duct air handling system space thermostatic controls building temperature by?
• To prepare for a lever test, the boiler should be pressurized to what fraction of its operating pressure?
• What do you do to attain complete combustion in a boiler?
• What is an accumulation test used for?
• Which boiler horsepower calculation uses the formula BHP = lb/hr x 1.08 divided by 34.5?
• What is the conversion factor used to convert feet of water head to psi for water systems?
• A boiler steam line 450 feet long expands approximately how many inches when heated from 70°F to 360°F?
• The oil in a refrigeration system is used for
• The height in feet of a liquid above a point such as pump suction is called what?
• How much excess air is required to burn coal?
• Which trio is involved in controlling steam pressure and monitoring the combustion air intake?
• Which condition is a boiler not protected against?
• A boiler has an input of 2800 and a loss of 600. Using the efficiency formula, what is the boiler efficiency?
• In an HVAC system controlled by a thermostat, what is the difference between the set point and the temperature at which the switch turns the system off called?
• A 15 psi steam boiler produces 8000 pounds of steam per hour. The minimum pipe size for the pipe leaving the boiler is approximately how many inches?
• Which valve arrangement is used to protect the boiler gauge by forming a water seal between the gauge and boiler water?
• What is the primary purpose of adding oil to the refrigerant?
• Why are tube ends on a fire-tube boiler beaded?
• Hard forming scale is primarily associated with which compound?
• What does a zeolite water softener system use as a means of regeneration?
• In a water-tube boiler design, where do the combustion gases travel relative to the water?
• What are the chemicals used to test water for hardness called?
• What is the BTU content of a gallon of #4 fuel oil?
• What size expansion tank is needed for a hot water system with 1000 gallons, 70 lb make-up, 70°F water in and 160°F water in the system?
• The stamp of approval on a nameplate signifies what?
• Which compound is not heat producing?
• How often should a complete external inspection of a boiler be performed?
• What are the two main types of controls?
• Which component is where the liquid refrigerant turns into gas and absorbs latent heat?
• A 5 inch pipe filled with water to a height of 75 feet will have what pressure at the bottom of the pipe?
• What is the volume of a cylinder with diameter 30 inches and length 20 inches?
• What is the vertical distance from the center line of the pump up to the top level of the supply tank called?
• A pump moves 250 gpm of water to a height of 75 ft with efficiency 96%. The horsepower required is approximately:
• Which element does not take an active part in the combustion process?
• Which coal has the biggest level of fixed carbon content?
• What is the flow rate, in gallons per minute, of water flowing through a 4 ft diameter pipe at a velocity of 12 ft/s?
• What is pump slip?
• A Boiler shall be designed and constructed in accordance with?
• What takes no actual action in combustion?
• In the pump horsepower formula HP = GPM x 8.33 x Height x Specific Gravity / (33,000 x Efficiency), what constant is used to convert GPM to horsepower?
• Which description best defines steam bound?
• A stoker that uses a feed RAM is a?
• What is the cross-sectional area constant used in the 2" pipe GPM calculation?
• What mechanical device is used to remove scale from fire tubes?
• What are the two primary functions of oil in a refrigeration system?
• Every discharge pipe on a safety valve should be at least how high?
• What is the wire that connects all components of a system to a physical ground or water pipe called?
• In an open type expansion tank how high should the tank be mounted?
• Recycled and filtered refrigerant can be used where?
• What is the total force on a valve with a diameter of 5 inches and a popping pressure of 200 psi?
• Convert 60°F to Celsius.
• What is the primary function of a three-element feed regulator?
• Which device is described as having a float mechanism that rises to allow steam through and resets on condensate?
• In a dual duct AHU, where are hot and cold ducts directed to the space?
• A boiler rated at 88,250 lb/h of steam per hour corresponds to approximately how many boiler horsepower?
• The boiler steam line is 350 feet long. During start-up the pipe is heated from 60°F to 350°F. A 350°F pipe will expand by approximately how many inches due to the temperature change?
• What is the area of a triangle with a base of 45 inches and a height of 26 inches?
• Water inlet into a building is 100 psig; if no booster pumps are used, what will be the pressure on the 10th floor if the building is 10 feet per floor?
• What is the safety factor when a system is rated at 1200 psi with a maximum pressure of 200 psi?
• Which hydrocarbon gas byproduct has the highest BTU value?
• Steam binding in a pump occurs when the suction static pressure falls below the vapor pressure corresponding to the temperature. True or False?
• Identify the component described as a device that functions as a check valve and keeps the pump primed.
• Which component in a boiler system is primarily responsible for vaporization by absorbing heat?
• What device is installed between the boiler drum and the steam gauge to create a protective water-tight seal for the gauge?
• What is the purpose of a suction accumulator?
• Where does liquid refrigerant vaporize and absorb latent heat?
• Proximate analysis reports which of the following?
• In a multi-zone air handling unit, the zone thermostat controls the zone temperature by?
• In the hardness calculation example, the product 17.1 × 0.5 equals 8.6. This value represents hardness in which unit?
• What is the total force on a 4 inch diameter safety valve disc when boiler pressure is 12 psi?
• What steam trap has one movable device that rises to allow steam through and resets on condensate?
• An accelerated circulation water-tube boiler is characterized by which feature?
• In a multi-zone air handler unit, the zone thermostat controls the zone temperature by?
• Boiler safety controls are designed to protect against which combination of conditions?
• What do you use to bank off a boiler and bring it back online without using the shut off valve?
• What is the cost per gallon of the chemical used in the example?
• What part in a refrigeration cycle discharges, high temperature pressure of vapor?
• What is used to remove moisture from a refrigeration system after a repair?
• Which component in a vapor-compression refrigeration system is responsible for absorbing heat from the refrigerated space?
• On boilers with both Quick opening and Screw-type blowdown valves, where must the Quick opening valve be located?
• Which compound is hard forming scale?
• During boiler shutdown, what is the first action you should take?
• What is the maximum distance apart for the Adamson Ring joint between furnaces?
• The color for an R-410A refrigerant cylinder is _______?
• By clicking on the exhibit the picture is a display of which safety valve type?
• Which statement best describes the relationship between pressure and floor height for a building’s water supply?
• How many BTUs are required to raise 2 lbs of water from 32°F to 212°F?
• Which item is listed on the nameplate along with the manufacturer, model, and serial number?
• What is shear?
• Which component is defined as a device that acts as a check valve and helps maintain pump prime?
• The purpose of the condenser in a refrigerant system is to?
• What is the volume of a cylindrical tank that has a 60 inch diameter and a 72 inch length?
• In a refrigeration system, which device governs the rate of refrigerant entering the evaporator?
• Which compound is not a heat producer?
• A reciprocating compressor operating with refrigerant R-410A head pressure of 476 psi and a suction pressure of 118 psi. What is the compressor's compression ratio?
• Why is oil added to the refrigerant?
• What does BTU stand for in heating calculations?
• A duplex pump with steam pressure 60 psi and piston diameters 10 inches and 6 inches achieves maximum pressure Pw equal to Ps times the piston area ratio. What is Pw?
• Boiler horsepower is calculated by dividing the steam production rate (lb/h) by which constant?
• What is an evaporator?
• Permanent hardness in boiler feedwater is caused by which combination?
• In boiler maintenance, what is the acceptable range for residual sodium sulfite?
• In the Zeolite Rejuvenation process, which step comes directly after Backwash?
• What is the temperature rise used in the expansion calculation from 70°F to 360°F?
• Which statement best describes the water-tube boiler design?
• Which two elements are the chief heat producing elements found in fuels?
• What is a foot valve?
• A boiler is rated at 86,250 pounds of steam per hour. What is the equivalent boiler horsepower?
• What is not an advantage of an economic boiler over a conventional HRT Boiler?
• What does the whistle on the top of the water column indicate?
• What is the total force on a valve with a diameter of 3 inches and a popping pressure of 150 psi?
• What is a hydrostatic test?
• What is the maximum pressure that a 15 x 9 x 10 duplex reciprocating pump can develop when operated with 125-psi steam?
• What stays are used to support the burner chamber in a Scotch Marine boiler?
• What is the name of an AHU that provides heating, cooling, ventilation, and air conditioning to multiple buildings or areas?
• What is the primary purpose of a crank case heater on a reciprocating chiller?
• Permits should be required for boiler work for how long?
• The flow area A used in the relief valve calculation for a 3-inch valve is approximately:
• Which statement is true about fire tube and water tube boilers?
• An air handler unit supplies a constant supply air temperature of 55 degree F to building spaces and includes a coil called _____air handler unit?
• A 3 element feed regulator senses which parameters to control water flow?
• Lead sulfide photocell is used as what kind of flame detector?
• In the total hardness formula TH = (C x 2.5) + (M x 4.1), what do C and M represent?
• On/off controls that activate devices using a single variable are called?
• What is the total force acting on a 2 inch pressure relief valve with a popping pressure of 125 psi?
• What do the three "T"s of combustion stand for?
• In a reciprocating chiller, which component prevents refrigeration migration?
• The Chief heat producing elements in fuels contents are?
• Which two quantities are multiplied together in the pipe expansion formula before applying the coefficient 0.0000065?
• Convert 185°F to Celsius.
• A flow control should be blown down when?
• Which type of pump can be started with the discharge valve closed?
• How often should you check the Low Water Fuel Cut Off?
• Which formula is used to calculate the volume of a cylinder?
• What is the primary function of the compressor in a refrigeration system?
• What kind of steam trap uses a simple float/disc that lifts?
• What mechanical device is used to remove scale from water tubes?
• Convert 85°F to Rankine.
• Which byproduct is known for having the lowest heating value?
• Where do you get sub-cooling reading?
• During a boiler hydrostatic test, the required water temperature is about 70°F. True or False?
• Which chemicals are used to combat corrosion in boiler water systems?
• During boiler blowdown, which valve is opened first and closed last?
• A steam line 600 feet long warms from 60°F to 350°F. With a coefficient of 0.0000065 per inch per degree, what is the expansion in inches?
• What is the result when a cylinder with bore 10 inches and stroke 24 inches has the piston travel two-thirds of the way?
• Which treatment is used to combat scale formation?
• How are high-pressure boilers equipped with Quick opening and Screw type blowdown valves blown down?
• How many steps are there in the Zeolite Rejuvenation process?
• Plume discharges from the cooling tower shall not be less than how many feet?
• Convert 185°C to Kelvin.
• A foot valve is installed at the end of which line, and what is its purpose?
• Which term is not one of the three T's of combustion?
• Refrigerant flow into the evaporator is controlled by ___________?
• What is meant by a pump becoming steam bound?
• What is the circumference of a circle with a 26 inch diameter?
• In the pipe expansion calculation, what unit should L be in if the coefficient is 0.0000065 per inch per degree Fahrenheit?
• At what percentage of boiler pressure should the safety valve lever be tested?
• What is the minimum discharge pipe height for a safety valve?
• What is the role of the terminal reheat coil in an AHU?
• Which factors are multiplied to compute the Average Evaporator Rate in the example?
• Which expression correctly gives the cross-sectional area used in calculating force on a circular valve disc of diameter D?
• What is the last protection against overheating in a boiler?
• A test on a 2" ID pipe with velocity 140 ft/s yields what GPM value?
• Using TH = (C x 2.5) + (M x 4.1), calculate total hardness (ppm as CaCO3) for 75 ppm Ca and 42 ppm Mg.
• What is the flow rate in gallons per minute for water flowing through a 6-foot diameter pipe at a velocity of 9 ft/s?
• If a condensate tank vent shows steam exiting at a temperature 20°F higher than normal, what is the likely cause?
• What type of valve allows a boiler to cut in online when the main isolation valve is open or closed?
• When a safety valve discharges, it should relieve the boiler so that the pressure does not exceed more than ______?
• What part in a refrigeration cycle discharges low pressure liquid?
• Which byproduct has the lowest heating value?
• Which gas byproduct is associated with the greatest heat value (BTU)?
• The removal of moisture from air using a cooling coil is called _________ dehumidification?
• LWCO stands for what in boiler protection?
• If 12 floors are each 10 feet tall, what is the approximate pressure on the 12th floor given a ground level pressure of 100 psi and the head conversion 2.31 ft per psi?
• When is a pump steam bound?
• What is the component where liquid is vaporized by absorbing heat?
• Which approach helps to achieve complete combustion in a boiler?
• What type of safety valve is the Crosby nozzle-type?
• In the boiler example, which equation expresses the relationship between Makeup, Condensate Return, Evaporator, and Blow Down?
• An air handler unit that has hot & cold air ducts connected to (molding boxes?) located in each building space is called a __________air handler unit?
• In the Zeolite Rejuvenation process, which step comes directly after Brine?
• What is the proper way of testing a safety valve?
• Which valve type would you place nearest the boiler in a blowdown line to ensure rapid opening?
• Which valve type is commonly used for throttling applications?
• What is the primary function of the mixing box in a duct air handling system?
• Water scales can be removed by boiling or raising water temperature. The effect is:
• What is the area of a triangle with a base of 20 inches and a height of 18 inches?
• During mud drum inspection, which action would you not do?
• The part of the refrigeration system that absorbs heat into the system is controlled by the ______?
• Where do you obtain a superheat reading?
• In the GPM calculation for a 2" pipe, what conversion factor converts cubic inches to gallons?
• Given a pump efficiency of 70%, delivering 1500 GPM against a 1000 ft head, what is the required motor horsepower?
• The term used to describe the energy content of a liquid column due to its height, used to estimate pressure at a point is called what?
• How much excess air is needed for proper combustion of coal, gas or oil?
• What compound produces soft scale in boiler water?
• How often do you check the high limit switch?
• A boiler hydrostatic test is performed by filling the boiler with water at about 70°F and raising pressure to 1.5 MAWP. True or False?