North Carolina Heating Group 3 (H3) Class 1 Practice Test

These questions are part of the practice quiz. Start practicing

• When a screen is installed at a combustion air opening, the mesh size shall not be smaller than what size?
• What is the estimated summer infiltration air quantity for an 1800 sqft residential structure with 8-foot high ceilings in Greensboro, NC?
• What role does a thermostat play in a heating system?
• What is a requirement for return air openings in relation to other appliances?
• Is it permissible in North Carolina to allow another contractor to use your license number for permits?
• Which refrigerant is commonly used in heat pumps?
• What is the function of a pressure relief valve in a boiler?
• What type of air economizer is required when 40% RH is maintained indoors in all seasons?
• What is the purpose of duct insulation?
• What does a thermal expansion valve do?
• What is the purpose of dust spot efficiency ratings for filters?
• What device is used to measure gas delivery pressure from the meter?
• What is a common symptom of a dirty air filter?
• Which of the following is NOT a component of the accounting cycle?
• What is the term used to describe a refrigeration system that includes a common condensing unit with multiple indoor fan coils?
• What is the minimum pipe insulation thickness required for a 2" chilled water line running at 42 degrees F?
• In a heat pump, what component changes liquid refrigerant into vapor during the heating cycle?
• What is the purpose of a smoke detector in relation to heating systems?
• Which factor is crucial when determining the flow rate of natural gas in a piping network?
• Is insulation required for an existing uninsulated sheet metal duct system when an AC coil and outdoor unit are installed in a ventilated crawlspace?
• A 1.25" diameter chilled water must be insulated with pipe insulation that is at least how thick?
• Who is responsible for setting, adjusting, and testing the controls of a boiler?
• What does "ton" refer to in HVAC terms?
• What is a potential consequence of ignoring a gas leak in your heating system?
• What advantage do programmable thermostats provide?
• In HVAC systems, which measurement indicates the efficiency of air transport within ducts?
• In buildings other than one and two family dwellings, what is the maximum smoke developed rating for pipe insulation in hydronic piping?
• What is the primary purpose of providing an access opening for appliances in a basement?
• What defines a two-stage furnace?
• Is an outdoor air economizer required on a data processing center in climate zone 4 with specified indoor conditions?
• What does AFUE stand for in heating systems?
• What is a standing pilot light?
• What is the minimum unobstructed width required for passageways around all sides of boilers?
• Which of the following is an approved procedure for commercial duct design per the 2018 NCMC?
• Duct liners must have a flame spread index of not more than what value?
• Liens must be filed within how many days of furnishing labor or materials on a project?
• How does improper insulation affect heating systems?
• Which type of heating system uses radiant heat?
• What is the minimum duration for testing a hydronic piping system, excluding ground source heat pump loop systems?
• Access panels that must be removed for servicing operations on vented wall furnaces shall not be what?
• What is the primary function of a ductless mini-split system?
• What is the height requirement for a roof-installed appliance's access point above grade?
• What measurement is used to indicate the effectiveness of insulation in ducts?
• How can you improve the energy efficiency of a heating system?
• What is a common cause of short cycling in heating systems?
• Where should air filters be located according to code requirements?
• What is the typical indication of a clogged filter in a heating system?
• What is the minimum size for a copper tubing fuel-oil supply line?
• What common issue can cause a heating system to be less effective?
• What are common signs of a gas leak in heating systems?
• Which heating system typically requires water to operate?
• What is the primary function of an expansion tank in a heating system?
• What is a common application of radiant heat in commercial buildings?
• When determining sizing for gaseous substances, what specific gravity is assumed for propane?
• In what scenario would a heat pump become less efficient?
• What is the function of a filter in a heating system?
• When heat is provided outside the building envelope in a commercial building, what type of heat is required?
• What is the required R-value insulation for supply air duct work run through a ventilated crawl space in climate zone 4?
• Which component is important for monitoring temperature in a heating system?
• Which type of heating system is known for its efficient heat transfer?
• Select the appropriate term that describes the area through which air flows in a duct or grill?
• How should underground ducts be protected if they are metallic?
• Drains, overflows, and blowdown provisions for cooling towers should be how connected to an approved disposal system?
• Which of the following criteria is not required when sizing a closed-type expansion tank?
• According to NC regulations, how must factory built barbecue appliances be installed?
• When should equipment have a protective coating if it’s installed underground?
• What is the main advantage of a heat pump?
• Brazing alloys shall not contain more than what percentage of phosphorus?
• What is the velocity in a 25" x 8" duct section with a flow of 1450 cfm?
• What safety feature do modern furnaces typically include?
• What percentage of gross pay is deducted for Medicare tax for employees?
• What is the term for heat transfer through direct contact?
• Which of the following could be an indication of a malfunctioning thermostat?
• What is the minimum horizontal distance that gravity outdoor air intake openings should be located from any noxious contaminant source?
• What is the difference between a boiler and a furnace?
• What is the maximum allowable length for a clothes dryer transition duct?
• What does a heat exchanger do?
• What determines the efficiency of a heating system?
• What is the primary function of refrigerant in a cooling system?
• When is a permanent fixed means of access required for rooftop installations?
• Cooling towers and fluid coolers must be provided with what feature?
• What is the purpose of a flue in a heating system?
• What is the minimum AFUE rating required for a gas-fired forced air warm air furnace of 120,000 BTU/hr in a commercial building?
• What is the benefit of a direct vent furnace?
• Is it legal in North Carolina to charge worker compensation insurance premiums to the covered employee?
• What is a standard characteristic of type K copper gas line?
• What does the term 'smoke developed rating' refer to in pipe insulation?
• What is a common effect of low humidity during winter heating?
• What is the heat gain for lights in a room with twenty fluorescent fixtures with standard ballasts?
• What does R-6 signify in duct insulation?
• The maximum horizontal spacing of supports for 3/4" CPVC tubing shall not exceed how many feet?
• Return air openings must be located a minimum of how many feet from the draft hood of another appliance in the same room?
• What type of fuel is commonly used in residential heating systems?
• For a cooling duct at a specific temperature, what is an important consideration for duct placement?
• What is the maximum interval at which PB piping installed vertically in a hydronic piping system should be supported?
• What is the minimum clearance from grade required for floor furnaces?
• What is the consequence of not following the rules for access to appliances installed on roofs?
• What can cause a heating system to short cycle?
• What does cfm stand for in HVAC terminology?
• What is the equation to calculate the design friction rate for a residential duct system?
• What safety device prevents overheating in a heating system?
• What is the minimum volume of indoor combustion air required for a room or space when the air infiltration rate is unknown, based on the input rating of the appliance?
• What is the benefit of variable speed fans in a furnace?
• According to the 2018 NCMC, what is the ventilation rate for people only in cubic feet per hour for a 5000 square foot general office building?
• How does a zone control system work?
• What could indicate that outdoor coils require cleaning?
• What is the primary function of a circulator pump in a hydronic heating system?
• How many BTUs does a standard fluorescent fixture contribute to heat gain?
• What defines large mercantile occupancies for the regulation of refrigeration systems?
• What is the largest size of annealed copper tubing allowed by code for refrigerant piping in field-erected systems?
• What does "BTU" stand for in the context of heating measurement?
• According to Manual N5, how many BTU/hr of latent heat will 235 occupants in a large store generate?
• What does the term ‘AFUE’ stand for in heating systems?
• What is one common type of radiant heating?
• What does a zoning system allow in a building?
• Which type of air connectors shall not pass through walls, floors, or ceilings?
• What type of heating system may provide both heating and cooling?
• What should be the depth of the cut or notch for studs in non-bearing partitions to ensure structural integrity?
• What is the velocity of air through a 24"x24" filter grill with 75% free area and an air volume of 2000 cfm?
• What is a potential hazard of a poorly maintained heating system?
• What is the role of a variable capacity compressor in a refrigeration system?
• What maintenance task should be done before winter?
• How much refrigerant must a refrigeration system containing more than it have stop valves installed?
• What size type K semi-rigid copper gas line is required for a structure with specific parameters?
• What material is used for ductwork to prevent heat loss?
• What is the function of the blower motor in a furnace?
• What type of heating system is known for its quick response time?
• What is the largest size of annealed copper tubing that can be connected with mechanical fittings?
• Does the code require two 1200 cfm air handlers installed on a common duct system to have duct mounted smoke detectors?
• According to the Miller Act, a payment and performance bond is required for any federal project above what dollar amount?
• What does HVAC stand for?
• Who is responsible for the correct location of fire dampers on building plans?
• Why is it crucial to perform regular maintenance on heating systems?
• What is one effect of accidents on job sites that is NOT employer-related?
• According to the 2018 NC energy code, duct systems operating at static pressures exceeding how many inches w.g. must be leak tested?
• What type of gas is the regulator set to deliver at the house?
• What is the boiling temperature of water in Celsius degrees?
• What are the electrical requirements for appliances located in attics and crawlspaces?
• For effective service, how should access panels be designed?
• If a refrigerant is at a temperature below its saturated temperature, what is it said to be?
• Where should steam blow off valves discharge?
• In non-bearing partitions, studs may be cut or notched to a maximum of what percentage of their depth?
• What is considered the ideal indoor humidity level during winter months?
• What duct insulation R value is required for a cooling duct located in an unconditioned space with an inside air temperature of 55 degrees F and an outside temperature of 80 degrees F?
• What is the maximum allowable velocity of air through a return grill?
• Where must a contractor file a notice and claim of lien?
• Which of the following is NOT a requirement for filing a lien?
• The appliance shut-off valve must be located no further from the appliance than what distance?
• In North Carolina, what defines a "prime contractor"?
• How many cubic feet of natural gas is allowed to flow down a 1.5" type K semi-rigid copper tube in a specific piping network?
• What happens in the event of a pump failure for condensate pumps?
• Is an outdoor air economizer required for a 120,000 BTU/hr rooftop heat pump in Guilford County, North Carolina?
• What should be considered when determining access for attic appliances?
• What type of maintenance is essential for ensuring efficient heating operation?
• What does "sizing" a heating system refer to?
• Which factor can reduce the required clearance from a mechanical appliance in certain installations?
• What is the operating velocity of a 20" round galvanized duct that is 100' long and delivers 2000 cfm of air?
• What is a benefit of using programmable thermostats?
• How often should HVAC filters be replaced?
• What is the minimum size duct required for providing combustion air to a 90,000 BTU/hr furnace with round horizontal ducts?
• During winter, what could be a sign that your heating system is not functioning properly?
• What should you check if your heating system is not producing heat?
• In general, a grease duct system serving a Type 1 hood must have a minimum clearance of how many inches from gypsum board wallboard attached to noncombustible structures?
• How is exhaust ventilation typically calculated for locker rooms?
• What is balancing a heating system?
• What is the importance of proper ventilation in a heating system?
• What is required for access to appliances installed on a roof located more than 16 feet above grade?
• When 24 gauge galvanized sheet metal is spaced 1 inch from a combustible wall, what is the maximum reduction in clearance permitted from 36 inches?
• What is the primary purpose of a heating system?
• Which refrigerant groups can use carbon steel pipe of schedule 40 for liquid lines between 2" and 6"?
• What does a carbon monoxide detector do?
• What should boiler operating instructions of a permanent type be?
• Bored holes shall not be closer than how many inches to the edge of the stud?
• How do building codes typically define the required R-value for duct insulation in conditioned spaces?
• What is a common type of fuel used in residential radiant heating systems?
• According to ACCA manual N5, what is the summer design condition in Greensboro, NC?
• What type of furnace has a required AFUE rating of 78% in commercial applications?
• What is the minimum number of threads per inch allowed on 1" schedule 40 pipes?
• Which material is commonly used for refrigerant piping in HVAC systems?
• How much concentrated load must floor registers resist without structural failure?
• What minimum thickness of concrete must metallic underground ducts be encased in?
• What is the purpose of a combustion air supply in heating systems?
• A confined space must have how many permanent openings when gas-fired appliances are installed and indoor combustion air is used?
• What is the recommended dust spot efficiency for filters in office spaces?
• What is one sign that a furnace may require repairs?
• What is a common maintenance task for heat pumps?
• How does a modulating gas valve operate?
• Who is responsible for application and compliance with the codes?
• Which of the following statements describes code restrictions on condensate pump usage?
• What size corrugated stainless tubing gas pipe should be left with the regulator for a system with a total connected load of 326,000 btu/hr and a design pressure drop of 0.5 in. w.c.?
• A certificate of test shall be provided for all systems containing a minimum of how many pounds of refrigerant?
• What is vital in ensuring gas-fired appliances operate efficiently in the presence of mechanical exhaust?
• Which heating system is known for its ability to deliver warm air directly into a space?
• What is the heat gain in BTU/hr for a dark colored commercial roof in Wilmington, NC, on a summer design day?
• What is the standard maximum pressure drop allowed across a gas pipe system for optimal performance?
• In a confined space application, combustion and ventilation air can be obtained from other spaces as long as what condition is met?
• What is the volumetric quantity of air moving in an 18"x18" duct with R-6 liner at a velocity of 1300 fpm?
• Required field tests of refrigerant containing parts may be performed using which of the following?
• What type of air connection is prohibited from passing through structural elements?
• Where mechanical exhaust interferes with the operation of gas-fired appliances, what is required?
• What are the minimum passageway requirements for a furnace located in a crawl space?
• What is the function of a thermostat?
• What is the minimum width required for an unobstructed passageway to access appliances installed in a basement of a dwelling unit?
• What is the maximum diameter for annealed temper copper tube used in refrigerant piping applications?
• What is the friction rate per 100 feet of a 10"x8" duct feeding a 390 cfm diffuser?
• What is the minimum required access opening size for attic appliance installations?
• What is the exhaust rate for a sports locker room in educational occupancies?
• Why is regular maintenance important for heating systems?
• What is the primary purpose of leak testing duct systems as per energy code guidelines?
• How far must holes bored in solid wood joists be located from the top and bottom of the joist?