HVAC D-2 license Practice Test

These questions are part of the practice quiz. Start practicing

• A single rooftop unit with 20,000 CFM supplies a three-story building. How many smoke detectors are needed?
• What gauge is used for high tension ignition wire?
• The condenser’s function is to remove what form of heat from the refrigerant vapor?
• What do you test an oil line with?
• The measure that uses 65 degrees Fahrenheit and the average temperature of any 24-hour period is called degree day.
• Which of the following heat sources should not be used with direct pipe radiant floor heating?
• An oil burner with porcelain electrodes cannot be cleaned white, what should be done?
• What type of pipe is not acceptable to use with R-717 refrigerant?
• Cast iron fittings shall not be used in ______ piping.
• Suction line accumulators protect the motor from slugging of which component
• A modern day residential oil burner motor operates at which RPM?
• What is the maximum allowable misalignment that is not considered a miter?
• What is the purpose of the access ports on a filter drier in a refrigerant system?
• If a source of contaminant is located within 10 feet of an intake opening, such openings shall be located a minimum of how many feet below the containment source?
• How is sound measured?
• The inability of the compressor to produce a high ______ indicates an intake valve leak.
• In an air conditioned room with a horizontal diffuser, when air drops occur, what is this type of throw called?
• What is the minimum wall thickness, in inches, of copper oil supply piping?
• What does the cad cell detect on an oil burner to ensure safe operation?
• Refrigerant relief valves are typically located on which HVAC component?
• On brazed joints, to make good joints you must what?
• Which statement is true about underground duct installation?
• What is the maximum control voltage for a boiler?
• In heat pump systems, two ______ devices are used.
• When like temperatures are experienced in a single zone system, it is likely the system is __________.
• Commercial refrigeration systems use many types of pressure regulating valves. Examples are _______ pressure (two temperature valves), and crank case pressure controls.
• The filler metal in brazed joints melts at what temperature range?
• The minimum amount of natural gas needed in the furnace fuel air mixture for proper burning is _____
• Ammonia is classified as which refrigerant category?
• The refrigerant control is located at what kind of point in package units?
• The 12-inch combustion air opening requirement applies to which space condition?
• Which material is used to construct a Class A vent?
• What is the horizontal hanger spacing for 3/4" nominal steel gas piping?
• What is the maximum length of a horizontal chimney connector?
• When testing an oil storage tank that contains 250 gallons, what is the testing medium used?
• In a gun-type oil burner, the primary control stops the burner if the flame goes out or if the flue temperature becomes too ______.
• What is the thread length of a 2 1/2 inch metallic gas pipe?
• A boiler with 225 degree water and 150 psi is called what?
• In oil burner terminology hollow or semi-solid refers to which component?
• Voltage tolerance for motors should be within what percent of the rating?
• Hard drawn copper tubing should not be bent.
• For wiring an oil burner, which gauge is commonly used?
• What determines an oil burner rating?
• A pressure differential switch is used to prove air flow in a hydronic system.
• The minimum working platform width for a remote condensing unit on a one-story roof sloped 3 in 12 is true: it is 30 feet or more.
• AFUE rating measures the efficiency of which equipment?
• What burner control prevents excessive water temperature in a gas fired hydronic system?
• In a gas supply line, what is the primary function of a drip leg?
• What gauge is required on ALL boilers?
• Which piping material cannot be used in underground gas piping?
• What is the maximum velocity of the air in square throat, sheet metal elbows without turning vanes?
• When field assembly of pressure vessels or boilers is required, a copy of the completed U-1 Manufacturer's Data Report must be submitted to the code official.
• What gauge should a 16-inch galvanized round duct be?
• In gas piping concealed in a wall, which fitting is used to create a branch connection?
• Which control prevents boiler overheating by stopping the burner at high temperature?
• Which value is closest to the heating value of propane gas in BTU?
• Which type of water supply is not recommended for heat loops encased in a floor?
• In HVAC terminology, the designation R728 refers to which gas?
• One of the best types of pipe to use with R-717 (ammonia) refrigerant is ___________.
• The minimum setback distance for a 250 gallon fuel oil tank from a property line is five feet.
• What is the Btu content per cubic foot of natural gas?
• What is the maximum current allowed on line voltage thermostats?
• High efficiency gas furnaces may use ______ pumps.
• In reference to cooling tower sump water, what is the ideal temp to test pH?
• Relays with sticky contacts should be
• Which statement about the gauging device on an oil tank is true?
• True or False: An unbalanced duct system will cause the temperatures to be the same in all rooms.
• What type of fittings are used to join dissimilar metallic piping materials in hydronic systems?
• What is the closest distance in feet a 250 gallon fuel oil tank can be from a property line?
• In a gas-fired hydronic heating system, water temperature is controlled by a temperature and which sensing element?
• Acetylene manifold pressures should not exceed how many pounds per square inch?
• When inspecting rigging equipment, what is the recommended action if damage is suspected?
• What hazard is produced when R-22 or R-12 is exposed to an open flame?
• Transferring heat from one object to another is called convection.
• An equalizer line should be used if the pressure drop between the inlet and outlet of the evaporator exceeds which pressure?
• In oil piping, what does OSV stand for?
• Which statement about joist notching and holes is true?
• The flash point for fuel oil #6 is 140 degrees.
• The pocket depth for the button punch snap lock when applied to 24 gauge sheet metal is 1/2 inch.
• The condenser's primary function is to to?
• For a fire-resistance rated assembly of less than 3 hours, what is the minimum damper rating?
• When testing an air-cooled condenser for leaks, which option would not be acceptable?
• Regarding cooling towers, the water temperature for pH testing should be between what degrees Fahrenheit?
• What temperature separates brazing from soldering?
• The common operating gas pressure for natural gas is ______ inches of water column, and LP gas is ______ inches of water column.
• Degree days are calculated using a base temperature of 65°F with the daily average temperature to quantify energy demand.
• Which statement about pressure regulating valves in refrigeration is true?
• Bearers should extend a minimum of ___ inches over the outside edges of runners.
• Horizontal pipes in a hydronic steam system should always slope towards the _________.
• The term hunting, applied to any mechanism, means that the mechanism:
• The King Valve is installed on which part of an AC system?
• For 24 gauge sheet metal using a button strap lock, what is the standard pocket depth?
• Which material is not suitable for venting low-heat appliances?
• Which statement about plenum rating for wiring is correct?
• Expansion joints of the slip type shall NOT be inside buildings or for thermal expansion.
• Draft reading over the fire for flame retention on a residential oil burner?
• How far off a crawl space floor must a duct be installed as a minimum?
• High-efficiency furnaces vent exhaust gases through which type of piping?
• What is the maximum length of a natural draft horizontal chimney connector for fuel oil?
• Liquid refrigerant entering the evaporator from the refrigerant flow control device is suddenly under which pressure?
• ARI 700 purification standards relate to reclaimed refrigerants.
• Defrost system controls are described as temperature initiated and
• There are ____ classes of air systems.
• Wood platforms shall be covered with opaque finishes.
• Desiccants are used in which component of a refrigeration system?
• Which component is used to reduce noise from gas pulsation in hermetic refrigeration units and may be located on both the intake and exhaust of the compressor?
• Underground metallic ducts not having an approved coating shall be encased in _________ inches of concrete.
• Which material is recommended for piping ammonia refrigerant R-717?
• How many watts equals one horsepower?
• What type of vent connector is used when located in an attic serving an appliance?
• Which control is used to monitor refrigerant liquid level?
• High tension ignition wire described as No. 14 stranded wire is in what gauge?
• According to NFPA 54, which piping material is not allowed to be used with natural gas?
• How many BTUs are in a cubic foot of natural gas?
• A speed variance of ______ can be made using an adjustable pulley.
• Copper water tube hydronic boilers has the lowest terminal mass per BTU/hr.
• The minimum inside radius of a bend in metallic pipe in a gas system is how many times the outside diameter of the pipe?
• The minimum intermittent exhaust for a residential bathroom is 50 CFM. True or false?
• During brazing, which gas is commonly purged through the line into the compressor to prevent fire or explosion?
• What is the main purpose of the condenser in a refrigeration system?
• How much combustion air is required to burn one gallon of fuel oil?
• Which distance is the minimum setback for an above-ground oil tank from a building (275 gallons or more)?
• Hydronic joints between polybutylene plastic pipe and tubing shall be _____ joints or _________-fusion joints.
• The unit used to express common operating gas pressure for natural gas is inches of water column.
• What is the purpose of the crankcase heater on an AC compressor?
• What is the min area of a duct supplying combustion air to a 152,000 BTU commercial fuel oil burner.
• Voltages must be within ______% of the motor rating.
• What is the minimum gas pipe testing time for a residential single family dwelling unit?
• Metallic pipe supports must not promote galvanization.
• What personal protective equipment would be used as fall protection?
• In determining head pressure for air-cooled condensers, the added degree value used with 35°F is
• A gas boiler rollout is considered to be:
• Refrigeration relief valves are usually on the liquid ______.
• What takes the safety switch heater out of the circuit when operating an oil burner with a stack-mounted primary control?
• When copper piping is installed beneath a concrete floor, which jointing method provides a reliable seal?
• What is the required ventilation for a 15,000 square foot auditorium?
• When an oil burner motor only starts when the shaft is first turned by hand, what is wrong?
• Which distance is the maximum for an ultraviolet scanner from the flame?
• Which substance would provide good scale prevention in an open cooling system?
• Geo-thermal systems are also referred to as geo-________.
• Scroll compressors are usually used in _______ and heat pump applications.
• Cryogenics temperature ranges from ______ to absolute zero.
• A pressure control for a condenser fan is operated by _______ pressure. the cutout temperature should be set to ten degrees below the desired evaporator outside surface temperature.
• The statement about wood platforms and finishes is true.
• An induced-draft blower is used to pull and exhaust the products of which process?
• Regarding package units, the refrigerant control is the ______ point between the high pressure side and the low pressure side.
• Which component is commonly at fault when the burner won't start unless manually rotating the shaft?
• In burner safety switches, the bi-metal element expands to do what when heated by the hot gas?
• A potential relay pulls in on a ______ increase.
• In a hydronic system, toward which component should horizontal piping be sloped to aid drainage?
• According to OSHA, how far must materials be kept from the edge of excavations?
• A ______ is a strap with means for securing it about the waist and for attaching it to a lanyard, or deceleration device.
• What is R728 commonly identified as in HVAC contexts?
• What is the maximum misalignment that is not considered a miter?
• Which of the following is a refrigerant capacity control used with the thermal expansion device?
• What is the minimum atmospheric vent size (in inches) of a 2 inch fuel line in a single burner boiler system?
• Where should a draft control device be installed if the manufacturer does not specify the location?
• Which statement is true regarding appliances installed under floors?
• A thermal device that opens its contacts when a motor heater coil uses too much current is a __________
• The untreated portion of gas piping outlets must extend a minimum of how many inches through a wall?
• What is the standard distance apart between electrode ends in the oil burner setting (the 3/16" end spacing refers to the ends, while the 1/8" is the ahead-of-nozzle setting)?
• What gauge of wire goes to an oil burner?
• Flame retention head oil burners usually run at how many RPMs?
• What are the electrical contacts called in the burner safety switch that are closed by the bi-metal element?
• A BTU is defined as the amount of heat required to raise the temperature of one pound of water by one degree Fahrenheit.
• Defrost controls for air conditioning and heat pumps can be temperature initiated/___________________
• There are four classes of air systems.
• Regarding heat pumps, which valve is used to change from heat to cool?
• Desiccants are used in
• A starter whose contacts open the power circuit when its control circuit is energized is said to have normally ________ contacts.
• A roof condensate drain should not drain into which drainage path?
• When climbing up a ladder, you should be facing it.
• A ____ is a rigid connection that holds one scaffold member in a fixed position with respect to another member, or building structure.
• When gas pipe is installed underground for an industrial building, it is encased in approved conduit.
• For an oil-fired appliance with a mechanical draft, the horizontal termination point must be at least how many feet from an interior corner of two perpendicular walls?
• A 6-inch diameter vent measures 20 feet vertical; what is the maximum horizontal length of the 6-inch, single-wall connector?
• The difference between gauge pressure and absolute pressure is the atmospheric pressure at sea level (14.7 psi).
• It is prohibited to vent an appliance through a pipe chase.
• A bypass plug is used on two-pipe oil systems; it is placed in the oil pump.
• The net free air area factor for a 12x12 louvers opening is 75%. Which option represents this factor in decimal form?
• A grid-tube evaporator is considered an evaporator. true or false?
• What is the maximum deflection angle of each miter joint in ductwork?
• Expanding soft copper to relieve another piece of copper of the same diameter is called?
• The thermal expansion device and the ________ tubes are two popular refrigerant capacity controls.
• The maximum size of an oil supply line shall be which of the following?
• Regarding servicing air cooled condensers, the correct pressure may be determined as follows. first, add ___ degrees to 35 degrees F.
• True or False: An unbalanced duct can cause noise and vibration.
• Where is silicon carbide igniter used?
• Absorption cycle systems water is the refrigerant, and ___________ is used as the absorber.
• Before attaching regulator to a fuel gas valve, the recommended action is to:
• T or F: A reciprocating compressor has less vibration than a scroll compressor.
• Test pressure should not exceed ___ psig on any oil tank connected to the piping.
• A 12\" x 12\" duct with 2000 CFM has an FPM of
• How many BTUs are in a cubic foot of LP gas?
• OSHA specifies a short-term slope of 1:2H:1V for excavations in type A soil up to what depth?
• In a hydronic radiant floor heating system, what device works with the thermostat to provide individual zone control?
• Installing tubing beneath the floor joist is NOT an option when installing hydronic floor heating systems.
• What is used to control capacity on commercial ac compressors?
• For a 6-inch vent with a vertical run of 20 feet, the maximum horizontal length of a 6-inch single-wall connector is 15 feet.
• HVAC draft readings are typically expressed in inches of water column.
• Hydronic radiant floor heating systems should not be installed under the _________.
• Which component of a high efficiency gas furnace is typically not found in a mid efficiency furnace?
• Which piping material uses solvent cement joints in HYDRO heating systems?
• The major difference between a relay, a contactor, and a starter is the size of the ______ they can handle.
• The statement 'Temperatures in all rooms are the result of an unbalanced duct system' is:
• Which valve is set at the adjustable heat anticipator on a gas thermostat?
• What is the cad cell purpose in a cad cell primary control?
• A roof condensate drain should not drain into a French drain.
• The best way to mount a thermostatic expansion valve sensing bulb is the horizontal position on the top of the suction line.
• Which component is described as being constructed of brazed cylinders with baffle plates mounted inside?
• What is the proper lighting device for an oxy-acetylene torch?
• In two-pipe hydronic reverse-return systems, each pipe circuit has the same length supply and return line.
• The operation of the sensing bulb depends upon the ________ pressure of a volatile liquid.
• Joints between different metallic piping materials shall be made with approved dielectric fittings or brass converter fittings.
• Which device is used when connecting instrumentation to a steam boiler to prevent backflow?
• The hourly rating on boiler labels is typically expressed in which unit?
• What is the maximum air pressure allowable in an air duct system
• Which component collects excess refrigerant on the low side (Suction Line) of a refrigeration system?
• What are the access ports on the filter drier used for?
• Reverse return is easier to _________ and each pipe circuit is the same length.
• Sound strength and sound pressure level (SPL) are rated in which unit?
• The diameter of any bored hole shall not exceed what fraction of the joist depth?
• What is the proper lighting device for an oxy-acetylene torch?
• What is the standard electrode setting ahead of the nozzle minimum in an oil burner, with electrode ends 3/16" apart?
• The terms hollow, semi-solid refer to what component of an oil burner?
• In refrigeration systems, which device prevents liquid refrigerant from returning to the compressor?
• What is the purpose of the firestat in an air handling unit?
• Which color corresponds to refrigerant R-11?
• Which component monitors refrigerant liquid level in a system?
• What does FPM stand for in HVAC calculations?
• During defrost cycles, which device is used to disable the compressor circuit?
• Which component most effectively reduces vibration transmission from a fan to connected ductwork?
• What is the minimum fire-resistance rating for the barrier that separates oxygen cylinders from other materials?
• Regarding vibration absorber, the flex absorber should be fastened to the unit or to a wall at the end pointing away from the vibration source.
• A suction line check valve is sometimes used on the ________ evaporators on multiple refrigeration systems.
• What is used with the thermostat to provide individual zone control in a hydronic radiant floor heating?
• What should the pressure be at the ejector nozzle in a steam jet cooling system?
• What is the maximum number of employees a boatswain's chair is designed to support?
• How many BTUs are in a cubic foot of propane per psi test?
• True or False: Exhaust from high-efficiency furnaces is vented outside the building through plastic (PVC) piping.
• Where must the draft control device be installed if the location is not specified by the appliance manufacturer’s instructions?
• Which boiler type is noted for having the lowest terminal mass per BTU/hr?
• Soot buildup in a heating appliance primarily affects efficiency by reducing which process?
• Another name for current in electricity is _________.
• What should be placed between the metal cap of the jack and the load when there is danger of slippage?
• Gas piping outlets that penetrate a wall must extend through the wall by at least
• What is the purpose of the equalizing line in a thermostatic expansion valve?
• What application would a sail switch be used in?
• A chimney for a residential low heat utilization equipment shall extend at least how many feet?
• The flex absorber should be fastened to the end closest to the vibration source.
• Which control is used to manage frost buildup on outdoor coils in heat pumps and air conditioners?
• In a confined space, the upper opening for combustion air must be within 12 inches of the ceiling.
• BTU is the abbreviation for what?
• In a steam boiler, which gauge is not required.
• In heat pump systems, which valve is used to switch from heating to cooling?
• What is the minimum height of the noncombustible barrier around oxygen storage?
• Where do you install the King Valve on an AC system?
• Under-floor appliance access opening for none fuel gas appliances: minimum size is 30 x 30 inches.
• What is the minimum airflow during a purge on a prefiring cycle on an automatic system for a water-tube boiler?
• Masonry is used to construct a Class A vent.
• When reclaimed refrigerants are tested and found that they meet ARI 700 purification standards they may be reused in another owner's equipment.
• Which device controls refrigerant flow into the evaporator?
• The equalizing line in a thermostatic expansion valve helps balance pressure drop between which component?
• For none fuel gas appliances under floors shall have a minimum access point of ____ x _____ for appliance access.
• Among the main control system types used, which one is listed alongside pneumatic, electronic, and fluidic?
• For bored holes in joists, the minimum distance from the top or bottom surface of the joist is:
• Ignition transformer voltage typical in oil burner systems is approximately how many volts?
• In a cascade refrigerating system, the arrangement means two or more refrigerating systems are connected so that one stage's evaporator cools the next stage's condenser.
• Fuel oil begins to come apart when subjected to a vacuum exceeding how many inches of mercury?
• Which of the following distances is not a valid placement distance for an ultraviolet scanner relative to the flame?
• If insulation gets wet, what would it do to the insulating characteristics of the insulation?
• In a confined space, the upper opening supplying combustion air to fuel burning appliance must be a maximum of how many inches from the ceiling?
• When does a crankcase psi regulator open?
• The maximum design operating gas pressure for piping inside a residential home shall not exceed _______ psi.
• The gas test pressure to be used shall not be less than ______ times the proposed maximum working pressure.
• Which device is used to stop oil flow if an oil line leaks?
• To clean the water side of the boiler after installation one pound of trisodium phosphate for each ___ gallons of water
• Suction line accumulators in heat pump systems primarily function as what?
• How many inches of vacuum should be used to test an oil suction line?
• An amount of gas less than ____ would be too lean.
• Approximately how many cubic feet of combustion air are needed to burn one gallon of fuel oil?
• Viscosity indicates the agility to flow at given _________.
• Geo-thermal heat pumps are also referred to as geo-________.
• The gas test pressure shall be not less than 1 1/2 times the proposed maximum working pressure.
• If the rotor is hitting the __________, the bearings must be replaced.
• Rotary compressors are used for which category of refrigerated appliances?
• If there is no barrier, what minimum distance must be maintained between oxygen cylinders and fuel-gas cylinders?
• A ____________ is an instrument used to measure the wattage consumed by an electric motor or an electric device.
• During brazing operations, purge gas is commonly used to prevent ignition. Which gas is typically used?
• The minimum soldering distance from plastic to metal compression on a hydronic line is 18 inches.
• In natural gas combustion, what is the acceptable range for gas content in the air-gas mixture?
• Centrifugal compressors are designed for use with large capacity systems. The lower end of the designed range is how many tons?
• A puff back that is caused by an accumulation of air-oil mixture in the combustion chamber that is ignited either a late spark or the hot refractory material results in what?
• The vacuum threshold at which fuel oil may break apart is measured in inches of mercury and is which value?
• Is voltage another way to measure electricity?
• Which device initiates the burner motor when a thermostat calls for heat in an oil burner?
• The cad cell on an oil burner detects what?
• What pressure is liquified petroleum gas fed to the burner?
• What happens when there is too much combustion air in an oil burner fuel mixture?
• In some refrigerating systems with an external open-type motor to drive the compressor, the crank case seals to seal the ______.
• A competent person is someone who is able to identify existing and predictable hazards in the surrounding area or working conditions that are unsanitary, dangerous, or hazardous to employees.
• When refrigerant reaches its critical temperature it cant exhaust as a liquid.
• A snap-action two-temperature valve is normally used with multiple ________ systems.
• Leak testing an air cooled condenser should be performed without removing all refrigerant from the system.
• Why is a plug in the external bypass part of two pipe fuel pump?
• If an appliance does not meet the code of exception, how high must it be installed in private gauge?
• A steam heated boiler operates at pressures not exceeding __________ psi for steam
• Force draft combustion blowers ______ air into the combustion chamber.
• Which is least compressible?
• If a refrigeration packing nut on a service valve is leaking, the correct action is to
• High pressure gun type oil burners are the most popular burners for
• Appliances located how many feet above the floor level should be provided with approved permanent means of access?
• What type of hydronic heating system uses diversion (monoflow) tees.
• What is the flash point of #6 fuel oil?
• What reduces the capacity of a refrigerant compressor?
• Which operation is generally discouraged for hard drawn copper tubing?
• Fuel oil begins to come apart when subjected to a vacuum in excess of 10 inches. True or False?
• According to IMC 2000 1208.1.1, ground-source heat-pump loop tests should be backfilled prior to inspection.
• On a gas thermostat, the adjustable heat anticipator is associated with which electrical parameter of the control circuit?
• SuperJet safety valves are used on industrial steam boilers rated at least how many psi?
• Which statement about the crankcase heater is true?
• The definition of brazed joints is: a gas tight joint obtained by the joining of metal parts with metallic fixtures or alloys which melt at a temperature of above _________ degrees F, but lower than that of the metal being joined.
• In a 2x10 floor joist, what is the maximum diameter of a bore placed 2 feet from the end?
• Are 24 gauge stainless steel sheet materials approved for use in duct construction?
• What type of switch is used to keep refrigerant levels within safe limits on some systems?
• In trench excavations, a safe means of egress must be located at a depth of at least how many feet to limit lateral travel to 25 feet?
• What is the required outdoor air CFM for a two-car garage in a single-family dwelling unit?
• When installing an AC system in an attic what is required?
• In a refrigeration cycle, the oil separator is installed immediately after which component?
• What is the test instrument used to measure current of electricity?
• For threading metallic pipe in a gas piping installation for 1" iron pipe, what is the specified thread size?
• A boatswain's chair is designed to support how many employees?
• In the new high efficiency furnaces, flue gases leave the furnace at approximately what temperature range?
• Why is a plug installed in the external bypass part of a 2 pipe fuel oil pump
• An oil safety valve is recommended for gravity-fed oil line systems to stop oil flow if the line leaks.
• What is the minimum intermittent bathroom exhaust in CFM for residential use?
• The purpose of desiccant in the refrigerant filter dryer is to
• A horizontal transvers scaffold member upon which the scaffold platform rests and which joins scaffold uprights is called a ______.
• A normally open control valve is ________.
• Which statement about a liquid receiver is correct?
• The condenser in the refrigeration cycle removes the _________ heat from the refrigerant vapor.
• A ____ is a design of straps which may be secured about the employee in a manner to distribute the fall arrest forces of over at least the thighs, pelvis, waist, chest and shoulders with means for attaching it to other components of a personal fall arrest system.
• When heating pipe is put in the ground what is used to keep heat from transferring into the ground?
• What is the best way to ground a circuit?
• Which statement correctly describes the mounting of a thermostatic expansion valve sensing bulb?
• What is the minimum distance in inches, an electrode for an oil burner, can be to the center of the nozzle.
• What resistance range should be established upon firing a fuel oil burner, when testing a cad cell?
• Evaporative cooling is a common greenhouse cooling system.
• Leak testing of an air cooled condenser should be performed while the system is charged with refrigerant.
• By how many degrees below the evaporator outside surface temperature should the condenser fan cutout temperature be set?
• Which material may be used on oil piping in residential installations?
• Unloaders are used to balance the ______ on a run cycle.
• During burner on testing, the resistance of a CAD cell should be within which range?
• What is the primary function of a drip leg in gas piping?
• Notching or cutting wood studs in nonbearing partitions is permitted up to 40 percent of depth.
• A compound gauge measures both pressure and ________.
• Draft reading indicates proper flame retention in a residential oil burner?
• Cutting or notching of wood studs not greater than 40 percent of their depth is permitted in nonbearing partitions.
• Which device is used to monitor liquid refrigerant level?
• In a return air duct supplying an air handler rated 2000 CFM or greater, which safety device is required?
• An OSV in oil piping is also called _______________
• Which statement about a suction line accumulator in a refrigeration system is true?
• In NFPA 54, CSST refers to which tubing material?
• What does CFM stand for?
• Sensible heat is measured by which temperature parameter?
• Underground gas piping for industrial facilities must be encased in approved conduit.
• What is the maximum vertical spacing for steel pipe?
• Which vent connector is used when the appliance is located in an attic?
• Which material is not approved as a flue lining for low-heat appliances?
• Oil tanks shall be equipped with which type of device?
• CPVC pipe joints in a HYDRO heat system shall be joined by solvent cement.
• What is the maximum vertical spacing in feet for steel hydronic pipe?
• Air in an occupied space must be kept moving to eliminate ________.
• An above-ground oil tank with a capacity of 275 gallons must be installed at a maximum distance of how many feet next to a building?
• A hole is required for piping 4 inches from the bottom of a 2x10 joist that's 12 feet long, the hole is 2 feet from the end of the joist. The maximum allowable size for the hole is what?
• Which material is not approved as a flue lining system for low heat appliances?
• How does the service person check gas pressure to the manifold of a gas burner?
• Oil burner ignition transformers have an output voltage of how many volts?
• Metallic ducts not having an approved protective coating shall be completely encased in a minimum of how many inches of concrete?
• The statement 'A high efficiency gas furnace does not need a chimney for removal of exhaust gas' is true.
• The pressure testing tool used to verify gas pressure to the manifold is a
• The voltage to a residential thermostat?
• Suction line filter driers have maximum allowable pressure drops; for low temperature units, the limit is not to exceed how many psig?
• For high-temperature suction line filter driers, what is the maximum allowable pressure drop in psig?
• An accumulator in a refrigerant system is a safety device that prevents liquid refrigerant from entering the compressor.
• What is the color code of R-11 refrigerant?
• The desired draft, measured over the fire with the burner in operation is what?
• Germicide lights is the most effective way to control dirt suck syndrome in a heat pump system.
• What is the maximum design operating pressure for a residential gas piping system?
• An equalizer line should be used if the pressure drop between the inlet and outlet of the evaporator exceeds 4 psi.
• If the refrigerant suction line rises vertically from the compressor, a trap must be installed at the ______ of the riser.
• Which process expands a soft copper tube to relieve another tube of the same diameter?
• A snap-action two-temperature valve provides rapid response to temperature changes in HVAC systems. It is commonly used with multiple evaporator systems.
• A natural draft system is designed to remove flue or vent gases under _________ static vent pressure entirely by natural draft.
• Joints between different metallic piping materials in hydronic systems shall be made with what fittings?
• Which of the following is not a pressure regulating valve type used in refrigeration systems?
• What is the horizontal hanger spacing for 1/2 inch nominal steel gas piping?
• How far from a fuel oil burner must an electrode panel be?
• What is the minimum distance an above-ground oil tank over 275 gallons can be installed next to a building?
• An ignition transformer increases voltage from 120 to _______ volts. An electronic ignitor spark generator supplies a 14,000 volt spark to ignite the oil.
• How are copper joints made when embedded in a subsurface floor?
• Control transformers are classified by their rating in which unit?
• Scroll compressors are typically used in which applications?
• The maximum allowable steam pressure for a steam heated boiler is
• In refrigeration terminology, low side pressure refers to which part of the system?
• After a boiler is installed, who is responsible for the startup?
• Underground approved duct should be encased and sloped to allow drainage.
• On industrial steam boilers the safety valves are required to be mounted in the vertical up position.
• Oil tanks shall be provided with means to determine the liquid level.
• In boiler operation, which color smoke indicates too much air?
• Which device is commonly used to measure air velocity in duct systems?
• In referencing a cooling tower, why does the drain continuously bleed water out of the pan?
• Flexible connectors may be used on oil piping in residential installations.
• A temperature/pressure control operates the burner on a gas fired hydro heat system.
• A float switch control may be used to control refrigerant levels.
• Which piping material is commonly used to vent exhaust from high-efficiency furnaces?
• In a gas piping system, the minimum inside bend radius for metallic pipe should be at least how many times the outside diameter of the pipe?
• When fuel oil is subjected to a vacuum in excess of how many inches of mercury does it start to come apart?
• In a natural draft ventilation system, the static vent pressure must be under what condition?
• What does a fusible plug do on the refrigerant side of a condenser?
• If a burner rated at 1.25 gph is installed in an enclosure with two combustion air openings, each 175 square inches free area, what is the total free area?
• If gas piping is concealed in a wall, which fitting is commonly used to create a branch?
• What is the minimum outdoor ventilation air for a 1000 sq ft theater lobby?
• Which statement best describes stratification in an air handler unit's mixed air plenum?
• For air conditioning and heat pumps, which control can be temperature initiated and temperature terminated?
• A filter dryer designed for use in the _______ has a solid core of desiccant.
• What material is not to be used to vent low heat appliances?
• What is the heating value of propane gas?
• Which document is required for field assembly of boilers and pressure vessels?
• In duct systems, traverse joints are typically sealed according to standard requirements.
• What is the minimum size of a single-wall metal pipe vent on a gas water heater?
• Which statement best describes stratification in an air handler unit's mixed air plenum?
• What is the minimum walkway clearance around a boiler?
• What is the max distance an ultraviolet scanner may be placed from the flame?
• The electronic ignitor spark generator provides a spark of what voltage to ignite the oil?
• The over-fire draft test reading on an oil burner is negative and approximately -0.02 inches of water column.
• Which component is used to sense air flow to control an HVAC system?
• Which device provides a 14,000-volt spark to ignite the oil?
• Unloaders are used to control capacity on commercial compressors.
• What thickness of polyethylene is commonly used to insulate buried heating pipes to limit heat loss?
• On a 208 volt meter the lowest allowable input voltage is
• What is the standard unit for the free area of combustion air openings?
• True or False: For a fuel oil burner installed in an enclosure rated at 1.25 GPH, 175 square inches is the free area needed for each of the two required combustion air openings.
• A gas meter must be located how many feet from the suction line?
• What is the maximum current allowed on line voltage thermostats?
• Regarding defrost, which control is used to block out the compressor circuit?
• In a residential gas boiler, the burner is controlled by the ___________.
• What is the correct vacuum level to test an oil suction line, according to common practice?
• Slope of AC suction lines away from the evaporator and downward toward the compressor is?
• NFPA 54 (EHD) stands for which of the following?
• Silicon carbide igniters are an example of which ignition type?
• Which statement correctly states the separation requirement for oxygen cylinders stored with fuel-gas cylinders?
• The speed of the driven unit can be varied by as much as ___% using a variable pitch pulley.
• What is the primary purpose of a high limit control in a gas-fired hydronic system?
• Which statement about venting appliances is true?
• Which statement about coatings on wood platforms is true?
• What color is the sight glass on a refrigerant system if moisture is present?
• Transfer plates are needed for dry hydronic radiant heating to mimic mass.
• What is the function of the cad cell in an oil burner?
• The thread length for a 2 1/2 inch metallic gas pipe is which of the following?
• A burner that forces in both primary and secondary air is commonly called what?
• What tubing is not to be bent?
• In large capacity centrifugal compressors, the upper limit is how many tons?
• What unit is used to measure gas pressure in HVAC systems, as commonly specified for operating ranges?
• Water cooled chiller systems are typically used in which applications?
• During heating mode, moisture condenses on the outdoor coil.
• Refrigerant leaks may be detected with a ________ leak detector
• Relief valves are typically installed on which component?
• Which type of joint is not allowed for copper or copper alloy tubing used for fuel oil?
• The maximum allowable notching of a nominal 2x10 wood stud on an exterior wall is 1 3/8 inches.
• Cad cell sensors respond to light; when the flame is present, the cad cell resistance changes in what direction?
• In standard ductwork fabrication, which seam is generally accepted?
• Hot surface ignition makes use of a _______ carbide ignitor that heats up to a red hot condition.
• On a duct system, what type of seam must be sealed to prevent air leakage?
• Metallic ducts not having an approved protective coating must be completely encased in a minimum thickness of how many inches of concrete?
• Rotary compressors are commonly used to power _______ refrigerated appliances such as window air conditioners, package terminal air conditioners and heat pumps up to 5 tons.
• How do unloaders affect the operation of commercial AC compressors?
• In a refrigeration system, oil separators are installed between the compressor and which component?
• When inspecting rigging equipment you notice what appears to be damage to the rigging. What should be done?
• Which color indicates moisture present in the sight glass of a refrigerant system?
• What must be provided when flame sensing detectors can fail in the flame proven mode?
• Joints between different metallic piping materials should be made with approved dielectric fittings or brass converter fittings.
• Underground metallic ducts lacking an approved coating must be encased in how many inches of concrete?
• What is the purpose of the filter drier on an AC system?
• What is the minimum outdoor ventilation air for a 1000 sq ft theater lobby? (in cfm)
• Why does soot reduce heating appliance efficiency?
• The pocket depth for the button punch snap lock when applied to 24 gauge sheet metal is 1/2 inch. Which gauge is used?
• A normally open control valve is open under which control pressure condition?
• What is the maximum notch allowed in a 2x10 exterior wall stud?
• ________ use many types of pressure regulating valves. Examples include evaporator pressure regulators, two-temperature valves, and case pressure controls.
• Suction line accumulators in heat pump systems are used as receivers for what?
• In a confined space, the upper opening that supplies combustion air to a fuel-burning appliance must be within 12 inches of the ceiling.
• What is the common operating gas pressure for natural gas in inches of water column?
• Which of the following would provide good scale prevention in an open water cooled system such as a cooling tower or evaporator condenser?
• Before connecting a regulator to a fuel gas valve, what should you do?
• Which is not true of a water cooled chiller system?
• When testing the CAD cell with the burner on, the ohmmeter reading should drop to between which range in ohms?
• Which device is typically used to switch large electrical loads in HVAC systems?
• In horsepower-to-watts conversion used in HVAC practice, one horsepower equals how many watts according to the material?
• In NFPA 54, CSST stands for which tubing?
• For a duct carrying heat from a furnace, what is the minimum clearance to combustibles?
• Chillers are used primarily for large industrial process cooling and commercial ______.
• Transfer plates in dry hydronic radiant heating are used to mimic the thermal mass of a poured structure.
• A balanced duct system generally results in what outcome?
• Which color smoke is typically observed when too much combustion air is introduced into an oil burner?
• What term describes a strap worn around the waist that can be connected to a lanyard or deceleration device?
• What material is an A-type vent made of?
• What term describes a structural block placed at the end of a platform to prevent slipping and to provide footing on sloped surfaces?
• In a cascade refrigerating system, one evaporator coil cools the next component. What is that component?
• Which statement about the crankcase heater is true?
• Which joint or seam must be sealed as directed by standard duct sealing requirements?
• The standard oil burner electrode setting ahead of the nozzle is 1/8 inch. True or False statement?
• What is the purpose of an equalizer line in an evaporator circuit?
• What is the draft reading from the over-fire draft test on an oil burner?
• AFUE rating indicates the efficiency of which equipment?
• Draft value for residential oil burners, measured over the fire with the burner in operation is approximately:
• In oil-burning appliance combustion products, the dew point is the temperature below which components condense on exposed surfaces.
• A fan cycling switch can be used to operate the _______ fan.
• The minimum bend radius is expressed as a multiple of which pipe dimension?
• The differential in the temperature between the switch turning on the system and the temperature which it turns it off is called
• In oil-burning appliance combustion products, the dew point is the temperature below which components condense on exposed surfaces.
• Acetylene manifold should not exceed 15 psi. True or False?
• Which statement about a liquid receiver in a refrigeration system is true?
• Which device is used to prevent refrigerant overfill in some systems?
• What is the temperature at which water vapor in the air will start to condense?
• Which of the following statements best describes a brace?
• How high above the roof should a Type 1 exhaust outlet terminate?
• When the burner is off, the cad cell looks into the dark combustion chamber. The bright light of the oil burner flame reduces the resistance in the cad cell, allowing ______ to flow through it.
• Cryogenics temperature range from what to absolute zero?
• For a duct measuring 40 inches by 22 inches with an air velocity of 1,500 feet per minute, the calculated CFM is approximately 9,167.
• Which term best describes a person who can identify hazards in the workplace?
• In systems using positive displacement compressors, the stop valves must be installed at which locations if the refrigerant charge exceeds 6.6 pounds?
• 1 horsepower is equal to 0.75 KWH.
• T or F Miters allowed in the systems having a design pressure greater than 50 psig
• In an oil safety switch for a refrigeration system, the oil pressure must always be above the ______ side pressure for oil to flow.
• A 152,000 BTU burner requires a minimum combustion air duct area of how many square inches.
• Which option is NOT considered a main control system type among those used in HVAC, based on the listed categories?
• For a 6-inch diameter vent measuring 20 feet vertically, the maximum horizontal length of a 6-inch single-wall connector is 15 feet.
• What is the minimum grate opening on an air intake grate in a residential application?
• A gas-fired system with 2 psi shall be tested with what medium?
• What is the primary function of the condenser in an air conditioning system?
• What water temperature differential is used in hydronic systems?
• For a fuel oil burner installed in an enclosure, the burner is rated at 1.25 gph. What is the free area needed for each of the two required combustion air openings?
• What does M.A.W.P. stand for?
• Which factor most directly determines an oil burner rating?
• Flame sensing detectors in flame proven mode must have a self-checking feature.
• To eliminate noise and vibration transmitted to critical rooms in an HVAC system, what component should be placed between the duct and the fan?
• During the heating cycle of a heat pump, moisture from the outdoor air will condense on the outdoor coil.
• Equipment installed at grade level must be supported on a level concrete slab or other approved material extending above adjoining grade or suspended a minimum of how many inches above grade?
• Cast iron fittings shall not be used in which piping service?
• In absorption cycle cooling systems, which substance serves as the refrigerant?
• What starts the burner motor on an oil burner when there is a call for heat from the thermostat
• When a refrigeration valve is back-seated, the gauge port opening is ______.
• A ______ is a multi-point adjustable suspension scaffold used to provide access to work inside chimneys.
• R728 refers to which gas in some HVAC contexts?
• What is the net free air in square inches of a 12 by 12 metal louver opening. (formula = total area x 75%)
• The minimum flash point of #2 fuel oil is 100 F. This statement is:
• What is the minimum flash point of #2 fuel oil in degrees Fahrenheit?
• Gas pressure is tested using a
• Who is typically responsible for starting up a boiler after installation?
• A ton of refrigeration represents the heat energy absorbed when a ton (2000 lbs) of ice melts during one ___ hour period.
• Which code or standard governs ground source heat pump loop system tests in this context?
• What happens after the hot contacts close in the burner safety switch?
• What is the minimum height off the floor that an oil-fired appliance is to be suspended?
• Copper oil supply piping thickness is typically expressed in what unit?
• To check air delivery and balancing of an air conditioning system, you would use which instrument?
• Miters are allowed in piping systems with design pressure greater than 50 psig.
• When connecting a pressure gauge or pressure control to a steam boiler, you should use an ______ siphon device.
• Insulation is needed when the fluid in the pipe ________.
• A direct-drive oil pump uses gear to move the oil.
• Which process allows joining two soft copper tubes of the same size without fittings?
• What is the determining factor in the rating of fuel oil burners?
• The maximum voltage for thermostats is 22 volts.
• What is the main required soldering distance from plastic to metal compression on a hydronic line?
• Doubling the diameter of a round duct increases its cross-sectional area by how many times?
• Two soft pieces of copper tubing of the same size can be joined together without fittings by __________ the pipe.
• Reclaimed refrigerants are refrigerants that have been processed to match new specifications by distillation and have been chemically analyzed to verify that the specifications have been met.
• What is the minimum test pressure of a 0.5 psi gas system?
• Which device is used to reduce noise in refrigeration equipment and may be located on the compressor intake and exhaust?
• During brazing operations, purge gas used to prevent ignition is typically which gas?
• Which device should be replaced if its contacts are sticky?
• In a 2x6 exterior load bearing wall, what is the maximum amount of material that can be notched?
• A recirculating air system with ducted and return air flow capacity of 3000 cfm serves one enclosed room. What automatic shutdown device is required?
• Where must safety valves on industrial steam boilers be mounted?
• What is not required on a steam boiler.
• For an oil tank piping system, what is the maximum test pressure?
• True or False: A respirator does not need to be worn when adding sulfuric acid chromate solution to prevent scaling in a cooling tower.
• White smoke in the flue from a gas-fired burner indicates the fuel-air mixture is too lean.
• The device used to gauge the contents of an oil tank is called a ________ device.
• A reverse return hydronic system is easier to balance because each pipe circuit is the same ______.
• What is the wiring rating called when conductors pass through ducts?
• Which factory seam is acceptable on ductwork?
• Cad cell primary control uses a cad cell to perform which action?
• Which component is commonly associated with high-efficiency furnaces and is not present in many mid-efficiency models?
• A direct drive oil pump uses ________ to move the oil
• What is the maximum horizontal length for a 6-inch diameter vent when installed with a 20-foot vertical run?
• The products of which process are exhausted by an induced-draft blower in many HVAC systems?
• OSHA accident prevention programs must provide for inspections of job sites by which type of person designated by the employer?