HVAC Unlimited Heating, Piping, and Cooling (S-2) License Practice Test

These questions are part of the practice quiz. Start practicing

• In the context of furnace efficiency, what does AFUE stand for?
• What is the standard gauge for high tension ignition wire covered with heavy plastic insulation?
• What action is typically taken if voltages are outside the specified percentage of the motor rating?
• How many inches of vacuum should you use to test an oil suction line?
• At what height must appliances be provided with approved permanent means of access?
• What is used to connect a pressure gauge or pressure control to a steam boiler?
• What is the diameter of a vent pipe on a 660 gallon or less oil tank?
• What is the output voltage of oil burner ignition transformers?
• A direct drive oil pump uses what mechanism to move the oil?
• Another name for current is ________________.
• What should the heat anticipator setting for a thermostat in a gas heating system match?
• True or False? The minimum working platform width when installing a remote condensing unit on a one story roof sloped 3 in 12 is 25% or greater = 30".
• What gauge is required on all boilers?
• What is the thread length of a 2 1/2 inch metallic gas pipe?
• What is the required ventilation for a 15,000 sq. ft. college auditorium?
• High pressure gun type oil burners are most commonly used for what type of applications?
• What height is required for Type 1 exhaust termination above a roof?
• Which standard governs the testing of Type B or BW vents?
• When the burner is off, what is the condition of the cad cell in the dark combustion chamber?
• What is the purpose of combustion air openings in a fuel oil burner?
• What is the optimal water temperature to test pH in a cooling tower sump?
• True or False? A liquid receiver is permanently connected to a refrigeration system for the storage of liquid refrigerant.
• What type of heat transfer occurs through a fluid or gas due to temperature differences?
• What is the main purpose of a condenser in an air conditioning system?
• True or False: A temperature/pressure control operates the burner on a gas-fired hydro heat system.
• At what reading is a cad cell considered to have failed during testing?
• A steam heating boiler operates at pressures not exceeding what value?
• What should be done if damage is noticed on rigging equipment during an inspection?
• Is it true that a higher value E.H.D. indicates greater gas capacity of tubing?
• If insulation gets wet, what effect does it have on the insulating character of the insulation?
• A natural draft system removes flue or vent gases under what type of static vent pressure?
• What should be done if the water supply in the heating loop is found to be unsuitable?
• How far must an electrical panel be from a fuel oil burner?
• In terms of oil burner safety, what is the typical response of a primary control in case of a malfunction?
• What does a high limit control in a boiler prevent?
• Which type of seam must be sealed on a duct system?
• What instrument is used to measure the current of electricity?
• What is a device used to provide adjustable access for work inside chimneys?
• Hydronic radiant floor heating systems should not be installed below which structural element?
• What is the maximum depth for notching on the ends of wood joists?
• How high must an appliance be installed in a private garage if it does not meet the code exception?
• In terms of water heating, what is the primary factor in determining BTU output when changing temperatures?
• According to OSHA, what is the maximum allowable slope for excavations less than 12 feet in depth?
• What is the maximum allowable test pressure on any oil tank connected to the piping?
• Which standard must reclaimed refrigerants meet to be reused?
• What is the minimum atmospheric vent size for a 2" fuel line in a single burner boiler system?
• A supported scaffold consisting of a platform supported by brackets attached to building or structural walls is known as what?
• What device ensures ignition in an oil burner system?
• Which type of HVAC system uses a centralized unit to provide heating and cooling to multiple zones?
• What type of connectors may be used on oil piping in residential installations?
• What device is primarily used to measure relative humidity?
• Doubling the duct diameter of a round duct increases its capacity by how many times?
• True or False? High tension ignition wires are used to connect the ignition system to the combustion chamber.
• How many BTUs are in a cubic ft. of natural gas?
• In nozzle sizing for oil burners, what formula is used with input BTUs?
• What is the maximum percentage of material that can be notched in a 2" x 6" exterior load bearing wall?
• Which device is primarily affected by the ohmmeter reading in a cad cell test?
• What is the most commonly used material for fuel oil supply lines?
• True or False? Transfer plates are needed for dry hydronic radiant heating to mimic mass or poured systems.
• What is the amount of combustion air needed to burn 1 gallon of fuel oil?
• Should underground approved duct be encased and sloped for drainage?
• What is the primary action needed to ensure a good brazed joint?
• How can two soft pieces of copper tubing of the same size be joined without fittings?
• Transferring heat from one object to another is called _________________.
• Which type of connector can be used on oil piping in residential installations?
• The safety switch heater is removed from the circuit when what happens?
• An oil safety valve is recommended for which type of feed oil line system?
• What component is activated when the hot contacts close in a burner system?
• What is the minimum size for an atmospheric vent on a 2" gas pipe?
• What is the function of the cad cell in an oil burner?
• For a 6" diameter vent measuring 20' vertical, what is the maximum horizontal length allowed for a 6", single wall connector?
• What factor primarily determines the rating of fuel oil burners?
• Oil Tanks shall be equipped with a ________________ device.
• Which type of joint is prohibited for copper or copper alloy tubing used for fuel oil?
• True or False? On industrial steam boilers, safety valves are required to be mounted in the vertical up position.
• What does a thermostat do in an HVAC system?
• What is the maximum design operating gas pressure for a piping system inside a residential home?
• Under what circumstance is stratification desirable in an air handler unit mixed air plenum?
• True or False? The clear access opening dimensions for appliances under floors should be at least 22" by 30".
• What is the minimum clearance to combustibles for a duct carrying heat from a furnace?
• What is the PSI limit for a steam heating boiler?
• What is the maximum diameter of a hole that can be bored in a joist?
• What is the minimum size of a single wall metal pipe vent on a gas water heater?
• If an oil burner motor starts only when the shaft is turned by hand, what is likely the issue?
• What is the typical refrigerant used in residential air conditioning systems?
• What type of piping is prohibited from using cast iron fittings?
• What condition would prevent a burner from continuing operation in a gun type oil burner?
• Are flexible connectors allowed on oil piping in residential installations?
• At what temperature, above a certain threshold, is a brazed joint formed?
• What gauge of wire is used for an oil burner igniter?
• How should the specifications for clearances around a duct system be determined?
• What is the purpose of encasing underground gas pipes?
• Which system is implemented to control and regulate temperature, humidity, and air quality in an indoor environment?
• How many Watts are equivalent to one Mechanical Horse Power?
• What is the appropriate method for testing an oil line?
• A supported scaffold composed of framed squares which support a platform is referred to as what?
• What is the minimum air flow required during a purge in a prefire cycle of a water tube boiler?
• What type of gauge is commonly used to measure the pressure in a steam boiler?
• What is the maximum vertical spacing allowed for steel hydronic pipe?
• Which of the following materials is not to be used to vent low heat appliances?
• What HVAC component is designed to remove moisture from the air?
• True or False: The presence of white smoke coming from a gas-fired burner indicates that the fuel-oil mixture is too lean.
• True or False? On duct measuring 40" x 22", with air velocity of 1,500 FPM, the CFM is 9167.
• Sensible heat is considered the measurement of which temperature?
• True or False? An unbalanced duct system leads to consistent temperatures in all rooms.
• What material is recommended for joints in hydronic systems?
• True or False? Cooling tower sump water should always be tested at the same temperature.
• Which piping material is prohibited for use in underground gas piping?
• What is the maximum current allowed on line voltage thermostats?
• What does a cad cell detect in an oil burner?
• What does 'BTU' stand for in the context of HVAC systems?
• What is the minimum height, in inches, that an oil-fired appliance should be suspended off the floor?
• In HVAC systems, what is the main purpose of an Oil Safety Valve?
• How far should oxygen cylinder storage be kept from fuel-gas cylinders or combustible materials?
• What unit measures the cooling capacity of an air conditioning system?
• The space of secondary containment for an oil tank will be tested with a volume of what?
• A natural draft system is primarily used to facilitate what type of gas flow?
• Which of the following factors does NOT determine the performance of a fuel oil burner?
• A 12" x 12" duct with 2000 CFM's has an FPM of __________.
• When gas pipe is installed underground, it is typically what?
• What is a single-point adjustable suspension scaffold designed to support one employee in a sitting position called?
• What percentage of their depth can wood studs be cut or notched in non-bearing partitions supporting no loads other than the weight of the partition?
• True or False: When climbing up a ladder, you should face it.
• Which of the following is a key function of a thermostat in HVAC systems?
• Is water considered an uncompressible substance?
• A bearer refers to which of the following?
• What instrument is used to measure wattage consumed by an electric motor?
• What is the name of the wiring rating when passing through ducts?
• A normally open control valve is open at what air pressure?
• What is the maximum current online voltage for thermostats?
• True or False? The capacity of the air delivery system determines the firing rate of a fuel oil burner.
• For gas heating, what would be considered too lean for combustion?
• What is the net free air in square inches of a 12" X 12" metal louver opening?
• What component starts the burner motor on an oil burner when there is a call for heat?
• What takes the safety switch heater out of the circuit when operating an oil burner with a stack mounted primary control?
• What must be replaced if the rotor is hitting the motor?
• What is the minimum test duration for a commercial gas piping system with a volume of 12 cubic feet?
• When is it acceptable to reuse reclaimed refrigerants in another owner's equipment?
• What condition is indicative of a system requiring make-up air installation?
• What is the purpose of using an amp meter in HVAC systems?
• In an air-conditioned room with a horizontal diffuser, what is the term for the air that drops?
• What is the maximum percentage of air required in the combustion mixture for natural gas?
• True or False? Grounding a circuit by connecting it to a water supply pipe is safe practice.
• True or False? High Efficiency gas furnaces are more environmentally friendly than conventional furnaces.
• As used in NFPA 54, what does EHD stand for?
• True or False: It is prohibited to vent an appliance through a pipe chase.
• What is the maximum design operating pressure for a gas piping system in a residence?
• True or False? An unbalanced duct will cause noise and vibration.
• Which type of condenser is NOT water-cooled?
• Which heat source is not suitable for use with direct pipe radiant floor heating?
• What is the minimum distance for installing a 275-gallon above ground oil tank next to a building?
• What is the closest distance a 250-gallon fuel oil tank can be from a property line?
• In what application would a sail switch be utilized?
• Which joint or seam must be sealed as directed by standard duct sealing requirements?
• Which material is most commonly used for flue vent piping in high-efficiency furnaces?
• To drop the temperature of 20 pounds of water from 85 degrees F to 45 degrees F, how many BTU's need to be removed?
• What is the maximum length allowed for a horizontal chimney connector?
• When a flame is established, the hot gas passes over what type of spring?
• What does HVAC stand for?
• True or False? Carbon Monoxide can be harmful if unburned in a burner.
• Is it true that a fuel oil burner rated at 1.25 GPH requires 175 square inches of free area for its combustion air openings?
• True or False: Wood platforms can be covered with opaque finishes as long as the edges are marked for identification.
• How many CFM of transfer air is required for a single-family bedroom with intermittent use?
• In a gun type oil burner, what typically triggers the control to stop the unit?
• By what percentage can the speed of the driven unit be varied with a variable drive?
• What is the required CFM for make-up air in a residential dwelling with 2 bedrooms, 3 baths, and a 2-car garage during intermittent operation?
• What are the required label information items on boilers?
• True or False? A speed variance of 30% can be made using an adjustable pulley.
• What is the purpose of ductwork in an HVAC system?
• What is the minimum damper rating per hour for a less than 3-hour fire resistance rated assembly?
• What is indicated by black smoke during boiler operation?
• What is the minimum walkway clearance around a boiler?
• In new high efficiency furnaces, flue gases leave the furnace at ____________ to ____________ degrees F.
• True or False? A High Efficiency gas furnace requires a chimney for the removal of exhaust gas.
• Why must air in an occupied space be kept moving?
• True or False? As used in NFPA 54, CSST means Corrugated Stainless Steel Tubing.
• What is the consequence if the rotor is consistently hitting the stator?
• How many BTUs are in a cubic foot of LP gas?
• What is the difference between gauge pressure and absolute pressure at standard conditions?
• What condition indicates that a single zone system is in balance?
• True or False? A respirator does not need to be worn when adding sulfuric acid chromatic solution to a cooling tower.
• How are copper joints made when embedded in a subsurface floor?
• When reclaimed refrigerants meet ARI 700 purification standards, what may be done with them?
• What is the resistance range established upon firing a fuel oil burner when testing a CAD Cell?
• What is the maximum distance a gas shut-off valve can be located from an appliance?
• What is the maximum velocity of square throat, sheet metal elbows without turning vanes?
• What type of piping is not allowed for fuel oil piping?
• What is the purpose of a fire stat in an air handling unit?
• What is the flash point for #2 Fuel Oil?
• The efficiency measurement for furnaces is known as the Annual _____________ utilization rating (AFUE).
• What is the primary function of an expansion valve in an HVAC system?
• What is the minimum exhaust air requirement for a 2000 sq. feet dry cleaning facility using a type II dry cleaning system?
• When notching exterior load-bearing walls, why is there a maximum percentage specified?
• What type of person is defined as competent in identifying hazards in working conditions and taking corrective measures?
• An ignition transformer increases voltage from 120 to ___________ volts.
• What is the flash point of #6 fuel oil?
• What type of contacts does a starter have that opens the power circuit when the control circuit is energized?
• What is the maximum allowable manifold pressure for acetone?
• What is the specified size for threading a 1-inch iron pipe in gas piping installation?
• True or False? A balanced duct system ensures even temperatures throughout a home.
• Insulation is necessary when the fluid in a pipe reaches which point?
• What is the minimum intermittent exhaust that must be provided for a residential bathroom?
• What is the free area required for each of the two combustion air openings for a fuel oil burner rated at 1.25 GPH?
• What is the minimum test pressure for a 0.5 psi gas system?
• Induced draft blower motors primarily remove which byproduct?
• What does the hourly rating in BTUs indicate?
• What is defined as a strap with means for securing it around the waist in HVAC safety?
• When calculating CFM for make-up air, which of the following factors is NOT considered?
• Before entering a boiler for internal inspection, what must be done with the blow off, the main steam stop valve, and feed-water valves?
• The gas test pressure should be no less than how many times the proposed maximum working pressure?
• What does a heat exchanger do in an HVAC system?
• What is the major difference between a relay, a contactor, and a starter?
• Which component is typically absent in a mid-efficiency furnace compared to a High Efficiency gas furnace?
• Which type of refrigerant is commonly used in modern HVAC systems?
• True or False: Fuel oil begins to come apart when subject to a vacuum in excess of 10".
• Which of the following describes a body harness in fall protection systems?
• The maximum allowable notching of a nominal 2"x10" wood stud on an exterior wall is ____________ inches.
• When fuel oil is subjected to a vacuum in excess of what measurement in inches of Hg does it start to come apart for the second time mentioned?
• Is it true that like temperatures in all rooms would be a result of an unbalanced duct system?
• What sensing element is used to control water temperature in a gas-fired hydronic heating system?
• What is the primary energy source for heat pumps?
• What is the minimum inside radius of a bend in metallic pipe in a gas system relative to the outside diameter?
• What component is necessary for the safe operation of heating systems to prevent gas buildup?
• What is the primary function of an expansion tank in a hydronic heating system?
• Which of the following best describes induced draft blower motors' function?
• In HVAC terminology, what does "steam trap" refer to?
• How are control transformers classified?
• How is gas pressure typically tested?
• What happens when there is too much combustion air introduced into an oil burner fuel mixture?
• What is the purpose of insulation in HVAC systems?
• What is a rigid connection that holds one scaffold member in a fixed position to another member?
• Where is a silicon carbide ignitor commonly used?
• When testing the cad cell with the burner on, the ohmmeter should drop to somewhere between ____________ to ____________ ohms.
• What is the process of expanding soft copper to relieve another piece of copper of the same diameter called?
• What type of appliance requires a mechanical draft system?
• What is commonly used to prevent vibration in HVAC equipment?
• Which statement correctly describes redundancy in a two-pipe hydronic system?
• What type of measurement is critical for flame detection in combustion systems?
• What is the maximum allowable misalignment that is not considered a miter?
• What is the minimum temperature required to activate a fire damper in a standard duct system?
• Which instrument uses dry bulb and wet bulb temperatures to calculate relative humidity?
• What is the maximum allowable hole size for piping 4 inches from the bottom of a 2x10 joist, which is 12 feet long?
• What type of insulation is used to create a class A vent?
• Relays with sticky contacts should be _____________.
• What pressure is liquefied promethium gas fed to a burner?
• Sound is measured in which unit?
• True or False? An acetylene manifold should not exceed 15 psi.
• True or False? The maximum vertical spacing for steel pipe is 15 ft.
• What should the pressure be at the ejector nozzle in a stream jet cooling system?
• Which of the following is essential for proper duct installation underground?
• For a 208 volt motor, what is the lowest allowable input voltage?
• How far must a gas meter be located from a source of ignition?
• What is the minimum air flow required during a purge on a prefiring cycle on an automatic system for a water tube boiler?
• Which of the following materials is not approved as a flue lining for low heat appliances?
• What is the minimum wall thickness for copper oil supply piping?
• What is the minimum diameter for A/C condensate drainage?
• Which component is essential for the safe operation of gas heating systems?
• What is the common operating gas pressure for natural gas?
• Is the minimum inside radius of a bend in metallic pipe for a gas system 6 times the outside diameter of the pipe?
• What is considered an acceptable manifold pressure for toxicity from burns?
• What should be done if an oil burner with porcelain electrodes cannot be cleaned white?
• If there is no _____ movement within a room, the air will tend to stratify.
• What does achieving ARI 700 standards for refrigerants ensure?
• The dew point is defined as the temperature below which combustion products will what on exposed surfaces?
• In relation to gas pressure testing, what is the minimum pressure regardless of design pressure?
• What is the maximum pressure allowed in an air duct system?
• The operation of the sensing bulb is dependent on which type of pressure?
• What is the minimum gas pipe testing time required for a residential single-family dwelling unit?
• What is the standard pocket depth for button snap lock applied to 24 gauge sheet metal?
• To reduce noise and vibration in critical areas, what should be used between the duct and the fan?
• What is required when installing an air conditioning system in an attic?
• Which valve is used to control the flow of refrigerant in an HVAC system?
• What is the best method for grounding a circuit?
• What temperature separates brazing from soldering?
• What type of joint is used to connect polybutylene plastic pipe?
• Which safety equipment is described as allowing for fall protection while working at heights?
• What is the maximum control voltage allowed on a boiler?
• Hydronic joints between polybutylene plastic pipe and tubing shall be ______________ joints or ______________-fusion joints.
• How thick must concrete encasement be for metallic ducts without a protective coating?
• What type of measurement is used to classify control transformers?
• How far must holes bored in joists be from the top or bottom?
• A hydronic system with embedded joints in copper pipe will be joined by what method?
• What is the heating value of liquid propane gas?
• When gas piping is concealed in a wall, what is required?
• According to OSHA, materials or equipment posing hazards must be kept how many feet away from the edge of excavations?
• Each oil tank must be equipped with a device to determine what specific measurement?
• Which component should be checked if a relay is frequently malfunctioning?
• Floor registers must resist a concentrated load on a 2-inch diameter disc applied to the most critical area of the exposed face. What is the minimum load in pounds?
• What is the draft reading for the over the fire draft test on an oil burner?
• What is the measure that uses 65 degrees F and the average temperature of any 24-hour period called?
• What should NOT be used if an instrument is measuring the wattage of an electric device?
• What is the primary purpose of an air filter in an HVAC system?
• What is a common use of the units determining BTUs in gas applications?
• What is commonly used to prevent heat transfer when heating pipes are installed underground?
• What type of plug is used on two-pipe oil systems and is placed in the oil pump?
• What is the structural block used at the end of a platform to prevent slipping called?
• What is the maximum length of a Natural Draft horizontal chimney connector for Fuel oil?
• When should thermal expansion joints be used in gas piping systems?
• In which type of heating system is a flame retention burner primarily used?
• What is the minimum required clearance to combustibles for a boiler?
• At what point should a professional inspect the heat exchangers in a heating system?
• What does the term "hunting" refer to in a mechanical context?
• What is the minimum grate opening on an air intake grate in a residential application?
• For oil suction line testing, what vacuum pressure is required?
• How does the configuration of a reverse return hydronic system benefit its functioning?
• Which control is essential for maintaining the temperature of a cooling system?
• What gauge should 16" galvanized round duct be?
• Which code governs the installation of gas piping systems in many jurisdictions?
• What material is a type A vent typically made of?
• What does stratification in an occupied space refer to?
• What type of burner is most commonly used for residential purposes?
• What is the minimum area of a duct supplying combustion air to a 152,000 BTU commercial fuel oil burner?
• Modern day residential oil burner motors operate at __________ RPM's.
• What is the maximum distance for positioning an ultraviolet scanner from the flame?
• True or False? Copper water-tubed hydronic boilers have the lowest terminal mass per BTU/HR.
• Which heating system component helps prevent leaks in gas piping installations?
• When fuel oil is subjected to a vacuum in excess of how many inches of Hg does it start to come apart?
• What is the main function of a float switch in an oil burner?
• What is the typical voltage used for a residential thermostat?
• A chimney for residential or low heat utilization equipment must extend at least how many feet above the roof?
• What is the minimum percentage of natural gas required for combustion to take place?
• What does white smoke from the flue of an oil burner indicate?
• In HVAC, how is the output of a heating system commonly measured?
• Which type of hydronic heating system utilizes diversion (monoflow) tees?
• True or False: Provisions must be made to absorb thermal changes by using expansion joints of the bellows type or by using ball or swivel joints on gas piping.
• What is the primary purpose of a flex connector in HVAC systems?
• What is the minimum distance an above ground oil tank over 275 gallons can be installed next to a building?
• True or False: Metallic pipe supports must promote galvanization.
• What type of factory seam is acceptable on duct-work?
• True or False? The proper fuel draft for a residential oil burner is normally (-.02").
• What type of soil is referenced in the short term maximum allowable slope for excavations according to OSHA?
• While a boiler is operating, what does white smoke indicate?
• What condition must be met for effective combustion in fuel-burning appliances?
• Underground metallic duct without approved coating should be encased in how many inches of concrete?
• Bearers must extend a minimum of how many inches over the outside edges of runners?
• In a confined space, what should be the upper opening distance for supplying combustion air to a fuel-burning appliance?
• What should be the draft reading over the fire for a flame retention, residential oil burner?
• According to OSHA, who is designated by employers to conduct frequent inspections of job sites, materials, and equipment?
• True or False? In two-pipe hydronic reverse return systems, each pipe circuit has the same length supply and return line.
• True or False? Locking snap hooks used in a personal fall protection system can attach to a D-Ring if no other connector is attached.
• What is the minimum required soldering distance in inches from plastic to metal "compression" on a hydronic line?
• True or False: CPVC pipe joints in a hydro heat system are to be jointed with solvent cement.
• What does the abbreviation M.A.W.P stand for?
• What type of solution is effective for scale prevention in an open system such as cooling towers and evaporator condensers?
• Which type of gas has an operating pressure of 11.0 inches of water column?
• What primarily determines the rating of an oil burner?
• Which property of a volatile liquid affects the operation of a sensing bulb?
• What is the purpose of a drip leg in a gas line?
• True or False: A 1/2" pocket depth is the standard for a button punch snap lock when applied to a 24 gauge sheet metal.
• Cryogenics temperature ranges from __________ to absolute zero (-460°F).
• True or False? Guys, ties, and braces shall be installed according to the scaffold manufacturer's recommendations or at the closest horizontal member.
• What is a vital component of ensuring safety and efficiency in brazing operations?
• What type of vent connector is recommended when located in an attic serving an appliance?
• Which fittings should be used for joints between different metallic piping materials in hydronic systems?
• True or False? The flex absorber should be secured to the unit at the end facing the vibration source.
• Which devices are typically used for measuring pressure in HVAC systems?
• How is gas pressure checked to the manifold of a gas burner?
• What is the required CFM of outdoor air for a two-car garage in a single-family dwelling unit?
• In a confined space, the upper opening supplying combustion air to a fuel-burning appliance must be a maximum of _________________ inches from the ceiling.
• True or False? 24 Gauge stainless steel materials are all approved for use in duct construction.
• True or False? A temperature gauge is required on a steam boiler?
• What is the minimum diameter size of a fuel oil supply line?
• What is the horizontal hanger spacing for 3/4" nominal steel gas piping?
• True or False? Where field assembly of pressure vessels or boiler is required, a copy of the completed U-1 manufacturer's data report shall be submitted to the code official.
• What dimension is used for an elliptical manhole in large boilers?
• What is the primary function of a sail switch in HVAC applications?
• According to NFPA 54, which piping material is prohibited for use with natural gas?
• What is the diameter of a circular manhole opening for large boilers?
• BTU is the abbreviation for what term?
• A puff back is an ____________ caused by an accumulation of the air-oil mixture in the combustion chamber.
• What is the purpose of using expansion joints in piping systems?
• What is the formula for sizing nozzles for oil burners using output BTUs?
• What feature must be provided when flame sensing detectors can fail in the flame-proven mode?
• What type of burner is typically found in modern heating systems?
• Which harmful gases can be present in a boiler?
• What is a common issue that can cause an HVAC unit to freeze up?
• What is the correct water temperature differential for Hydronic Systems?
• In a hydronic steam system, horizontal pipes should always slope towards which component?
• A gas fired system operating at 2 PSI should be tested using which substance?
• What is the minimum distance for a contaminated opening from a source located within 10 feet?
• Joints between different metallic piping materials should be made with which type of fittings?
• How many inches above adjoining grade must grade-level equipment and appliances be supported or suspended?
• A force draft combustion blower serves to do what with air?
• What is the term for the temperature at which water vapor in the air begins to condense?
• Which types of water supply is not recommended for heat loops encased in a floor?
• A roof condensate drain should not _______________________.
• What type of duct is a #28 gauge used for?
• In terms of safety, what is crucial when working with gas piping systems?
• What is the primary benefit of reverse return systems in piping?
• What is the length of the thread on a 1" piece of schedule 40 gas pipe?
• What is a common function of an air conditioning compressor?
• For non-fuel gas appliances, what is the minimum access opening required for appliance access?
• What is the main aim of preventive maintenance in HVAC systems?
• True or False? The maximum horizontal length of a 6" single wall connector on a 6" diameter vent measuring 20' vertical is 15".
• What is the minimum required height for a duct installed above a crawl space floor?
• The untreated portion of gas piping must extend a minimum of how many inches through a wall?
• What is the proper lighting device for an oxy-acy torch?
• Fuel oil begins to break down under a vacuum exceeding what pressure?
• How many BTU's are typically present in a cubic foot of natural gas?
• When testing an oil storage tank that contains 250 gallons, what is the testing medium used?
• What is the flash point of #6 Fuel oil?
• In a recirculating air system with a ducted return air flow capacity of 3000 serving one enclosed room, what automatic shutdown device is required?
• Are volts another way to measure electricity?
• True or False? A vibration absorber should be fastened to the unit or to a wall at the end pointing away from the vibrational source.
• What is the status of a gas boiler rollout?
• What component is used with a thermostat to provide individual zone control in hydronic radiant floor heating?
• Which type of control systems is NOT commonly used in HVAC applications?
• What is true about CPVC pipe joints in a hydro heat system?
• What device opens its contacts when a motor heater coil uses too much current?
• What is the maximum deflection angle allowed at each miter?
• True or False? Superjet safety valves are utilized on industrial steam boilers rated at 3000 psi or more.
• A pressure differential switch is used to prove flow in a ______________ system.
• What solution provides good scale prevention in an open water cooled system, like a cooling tower?
• True or False: Convection is the transfer of heat from one object to another.
• How many kilowatt hours is equal to one horse power?
• What is the purpose of the cad cell in a cad cell primary control?
• If a contaminant source is within 10 feet of an intake opening, how far must the opening be below the contaminant source?
• In a reverse return hydronic system, what characteristic makes balancing easier?
• What happens to smoke color when there is too much air in the fuel mixture?
• What is the purpose of a plug in the external bypass part of a two pipe fuel pump?
• True or False: The minimum amount of natural gas needed in the furnace fuel/air mixture for proper burning is 4%.
• In a scaffold system, how often should guys, ties, and braces be placed vertically for scaffolds wider than 3 feet?
• What is the purpose of a crankcase heater in an air-to-air heat pump?
• What does the acronym EPA stand for in HVAC contexts?
• What is another term for an Oil Safety Valve used in oil piping?
• Hard drawn copper tubing should not be ____________.
• What component is crucial for balancing a reverse return piping system?
• In a residential gas boiler, what component controls the burner operation?
• True or False: Miters are permitted in systems with a design pressure greater than 50 psi.
• Which personal protective equipment is typically used for fall protection?
• The terms 'Hollow' and 'Semi-Solid' refer to which component of an oil burner?
• An ammeter is an instrument used to measure which of the following?
• True or False? An oil fired appliance with a mechanical draft system requires a termination point a minimum distance of 3 feet from an interior corner of two perpendicular walls.
• All systems containing more than how many pounds of refrigerant in systems using positive displacement compressor shall have stop valves installed?
• What does the Annual Fuel Utilization Efficiency Rating measure in a gas-fired furnace?
• What is the common operating pressure for natural gas in water column inches?
• High efficiency gas furnaces may use which type of pumps?
• In accordance with OSHA protection, what term describes a person who examines the ground in excavations?
• What should be done before connecting a regulator to a fuel gas valve?
• How high above the roof should an exhaust (Type 1) outlet terminate?
• After a boiler is installed, who is responsible for the start-up?
• Which component of an HVAC system is primarily responsible for the removal of heat from the air?
• Flame retention head oil burners typically operate at what RPM?
• Why does soot reduce the efficiency of heating appliances?
• Voltages must be within what percentage of the motor rating?
• What is the correct manifold pressure for a boiler using L.P. gas?