ESCO Heating 208 Practice Test

These questions are part of the practice quiz. Start practicing

• If a technician determines that a natural gas furnace has a defective heat exchanger, what should they do?
• In what situation is it recommended to perform a leak check on a refrigerant system?
• What function does the accumulator serve in a refrigeration cycle?
• What is the primary role of insulation in an HVAC system?
• Liquefied petroleum (LP) gases include which of the following?
• What role does the condenser coil play in the HVAC system?
• For every cubic foot of natural gas burned, how many cubic feet of flue gas are produced?
• What could cause a furnace to cycle off shortly after starting up, with the blower not turning on?
• A natural gas (standing pilot) furnace usually requires what gas pressure at the manifold and burners?
• A technician measures 5.5 amps using a clamp-on ammeter on a thermostat wire. What should he set the heat anticipator to?
• What is the impact of refrigerant leaks on HVAC systems?
• What tool is typically used to clear a clogged pilot assembly orifice?
• What switch must operate properly before the ignition sequence in a gas furnace with an induced draft fan?
• How does a two-speed compressor improve energy efficiency in HVAC systems?
• Why is it crucial to balance duct systems in HVAC installations?
• What is the reason for a crossover on a gas burner?
• What is a primary function of an energy recovery ventilator (ERV)?
• In a heat pump, what is the function of the reversing valve?
• All condensing furnaces manufactured after 1992 must have an AFUE rating of at least:
• What could cause unusual noises in an HVAC system?
• What are the effects of excessive indoor humidity?
• A gas furnace with an induced draft blower is classified as which category by the National Fuel Gas Code?
• Why is refrigerant charge important in an HVAC system?
• What is one negative effect of excess moisture on HVAC systems?
• If the pilot assembly orifice of a spark ignition furnace is completely clogged, what should be done?
• Which issue can be identified by observing yellow burner flames?
• What is the purpose of ductwork in an HVAC system?
• How can cleaning condenser coils improve system efficiency?
• According to the National Fuel Gas Code, what is the maximum pressure drop allowance for gas piping?
• How high above the floor should a technician install a thermostat?
• Which component is responsible for controlling gas flow to the burner in a gas furnace?
• In heating systems, what does the term 'W.C.' stand for?
• What is one of the main benefits of using an energy recovery ventilator (ERV)?
• The ignition temperature of LP gas is:
• In HVAC terminology, what does 'static pressure' refer to?
• At what gas pressure will redundant gas valves on furnaces shut down?
• Which factor can lead to a frozen evaporator coil in HVAC systems?
• What could cause large amounts of soot in a heat exchanger of an LP gas furnace that was converted from natural gas?
• A technician starts up a standing pilot furnace, but the main burners light and the furnace cycles off after 30 seconds. What might be the issue if the blower did not activate?
• What is the specific gravity range of natural gas?
• When is the best time to assess the efficiency of an ERV system?
• A furnace blower motor rated at 115 VAC has what allowable voltage variance?
• Furnace limit switches are wired in series with which component?
• Why is it important to seal ductwork?
• What should be monitored to ensure effective heat exchange in an ERV?
• What is the key function of a temperature limit switch?
• What is the National Electrical Code classification for thermostat wire?
• What is the typical operating temperature range for an air conditioning system's evaporator coil?
• What is the purpose of a filter in an HVAC system?
• What is the term for the air mixed with natural gas in a burner?
• What is a potential safety hazard associated with carbon monoxide when operating appliances?
• What action should be taken after repairs or component replacements in a refrigerant system?
• What maintenance task is essential for keeping evaporator coils efficient?
• What refrigerant is commonly used in modern residential HVAC systems?
• At what temperature should the vent safety switch on induced draft furnaces typically open?
• Which safety feature is responsible for shutting off the HVAC system if airflow is obstructed?
• What should be prioritized to maintain good indoor air quality when using an ERV?
• What is the primary function of the compressor in a split system air conditioner?
• What could cause an HVAC system to short cycle?
• What effect does a properly calculated load have on HVAC efficiency?
• A homeowner's furnace makes a loud bang upon ignition. What should the technician check first?
• A technician is using an extension ladder to work on a rooftop unit. How far should the top of the ladder extend beyond the support point?
• A spark ignitor operates at what voltage AC?
• What could an inconsistent thermostat reading suggest?
• Which condition would trigger a temperature limit safety switch to shut off the burner?
• What is the ignition temperature range of natural gas?
• What is the significance of proper airflow in an HVAC system?
• What property of refrigerants is crucial for determining their efficiency?
• The cut off plate is a component found in which part of a heating system?
• What might be suspected if a technician lights a spark-type ignition furnace, but the spark igniter continues to spark after the main burners light?
• A "spud" or burner orifice is used to control what aspect of a gas burner?
• Why is proper cooling performance significant in refrigerant systems?
• What will be the consequence of failing to polarize a replacement low voltage transformer in an electronic ignition furnace?
• What are the factory settings for a standing pilot furnace with a bi-metal fan control?
• What function does a damper serve in a duct system?
• What should the LP gas pressure supplied to the gas valve typically be?
• Which of the following is a common issue if a furnace will not light due to a clogged pilot assembly orifice?
• What is a primary cause of "Flashback" in gas furnaces?
• What is the purpose of an expansion valve in an HVAC system?
• How does a dirty air filter affect HVAC system performance?
• A furnace with a hot surface igniter will not light. What should the technician check before replacing the igniter?
• Type B vent pipe must be kept at least _____ from combustible materials.
• What does the acronym 'HSPF' indicate in heat pump systems?
• A gas furnace installed at altitudes above what height needs adjustments to operate properly?
• How much combustion air is required to burn one cubic foot of natural gas completely?
• What is the ideal indoor humidity level for comfort?
• What are the two standard gauges for thermostat wire?
• Which instrument is best for measuring excess air in the combustion process?
• A dedicated vent system is defined as what?
• Which type of metallic conduit is recommended for indoor use only?
• What symptoms might suggest an issue with a heat exchanger?
• What does a high altitude setting in a gas valve typically require?
• What is the acceptable percentage of carbon monoxide (CO) in a sample of flue gas?
• When installing a Category IV two-pipe vent system that terminates through the roof, the elbow for the combustion air intake should:
• Why is regular maintenance important for refrigerant systems?
• If the vent system of a gas furnace is obstructed, which symptom may appear?
• What is the recommended frequency for replacing HVAC air filters?
• What is the formula used to represent airflow in heating systems?
• When setting up a gas furnace, what safety device should be checked before operation?
• What is the function of a vent limiting orifice in a redundant gas valve?
• For service access, a gas furnace should have a minimum clearance of how many inches?
• What is the purpose of using a specific type of solder in gas line installations?
• A gas furnace is to be installed in a garage. The burners and ignition sources must be located ______ above the floor.
• What is the difference between a single-stage and a two-stage HVAC system?
• When starting up a 15-year-old natural gas furnace, the burner flames wave in one corner after the fan starts. What might be the cause?
• A good thermocouple should read approximately how many millivolts on a D.C. meter?
• What is the basic operation of an air handler?
• How does the specific gravity of natural gas compare to air?
• How does a hi-metal fan switch operate the blower motor on a gas furnace?
• What is one common indicator of a refrigerant leak?
• If flames "roll out" during the main ignition of a standing pilot furnace, what is the likely issue?
• What can be expected from the energy recovery process in an ERV?
• How is the fan cycled during heating in a gas furnace with an electric control board?
• What can result from poor airflow in an HVAC system?
• What is a typical vent stack temperature for a Category I furnace?
• How do energy recovery ventilators (ERVs) improve energy efficiency?
• Why is load calculation important for HVAC system sizing?
• A fan motor is rated 1/3 HP at 120 volts. Approximately how many amps will the motor draw?
• What instrument would a technician use to calculate return airflow to a furnace?
• What is the minimum recommended clearance between the front of a gas furnace and the closet door where it is installed?
• Which type of burner is most commonly used in induced draft furnaces?
• How does the principle of thermodynamics apply to heat pumps?
• How does outdoor temperature affect refrigerant pressure in HVAC systems?
• What is the maximum allowable temperature rise through a furnace heat exchanger?
• What is a primary result of properly insulating an HVAC system?
• In what scenario would you recommend a zone control system?
• When venting Category I furnaces, where is the appropriate location to adapt to a larger vent pipe?
• Which factor primarily controls the cycle of a gas furnace fan?
• Gas piping should be installed with a pitch of what per 15 feet?
• If voltage is applied across two speed terminals on a fan motor, what is the likely outcome?
• How can a homeowner identify poor insulation?
• What happens if gas piping is not sized correctly?
• What does a higher SEER rating indicate?
• What does an inshot gas burner utilize to improve combustion?
• What is a common sign of a malfunctioning limit switch in an HVAC system?
• Burning one cubic foot of natural gas will produce _____ BTUs.
• A BTU is defined as the amount of heat required to raise the temperature of one pound of water by how many degrees?
• What does a gas valve with 100% shut off indicate?
• To change the speed of a belt driven blower, what should the technician do?
• What is the purpose of a spoiler screw located on a burner?
• If a technician reads 2 Ohms between the common and low speed wires of a 120 VAC furnace motor, what can the technician conclude about the winding?
• How does the location of a thermostat affect system performance?
• A technician needs to run thermostat wire 75 feet. To avoid a voltage drop, which gauge should the technician use?
• What benefit does the fresh outdoor air provide in an ERV system?
• A customer reports that a six-month-old furnace stops heating only on very cold nights. What might the technician suspect?
• How is a Ductless Mini-Split different from traditional HVAC systems?
• Where should pipe joint compound be applied?
• Type B Vent pipe consists of an inner and outer pipe. The inner pipe is typically made of what material?
• What is the formula for calculating BTUs?
• What reading would a technician expect between the high and low speed wires on a 120 VAC furnace motor if the winding is open?
• What is a common reason for a furnace blower motor to fail?
• What is one reason for low efficiency in a refrigerant cooling system?
• What is the maximum static pressure for a typical gas furnace blower system?
• In a natural gas heating system, what is the function of the gas manifold?
• The proper chemical name for natural gas is:
• Where is a fire stop support plate located in a dedicated vent system?
• What indicates a potential issue within a refrigerant system?
• What purpose do fuseable links serve on a furnace?
• What is the primary role of a flue baffle in a heating system?
• Which component is mainly responsible for cooling the air in an HVAC system?
• What is the appropriate instrument for measuring carbon dioxide levels?
• Which of the following best describes the purpose of a draft diverter?
• What is the primary function of thermal expansion valves?
• What type of solder is recommended when installing a copper elbow on an LP gas line?
• Typical vent or stack temperature of a Category III furnace is:
• How much current does a typical flame sensor produce?
• What is the "trial for ignition" or "flame proving time" for direct spark ignition systems?
• What is typically the first step in troubleshooting a furnace that does not reach the desired temperature?
• What is the role of a fusible link in a furnace?
• What is the primary concern when installing gas appliances?
• What type of solder should be used when a technician solders a spade connector to a wire?
• What purpose do fan time/temperature delay switches serve in gas furnaces?
• How many BTUs are produced by burning one cubic foot of Liquefied Petroleum gas completely?
• Which factor should be checked if the burner flames are not stable after ignition in an old furnace?
• What are signs that indicate a thermostat may be failing?
• Which type of gas valve provides complete shut off?
• What are the advantages of using a programmable thermostat?
• What is essential for maintaining proper combustion in gas furnaces?
• A gas furnace will not light and locks out during the process with 19 VAC at the gas valve. What should the technician conclude?
• The "bonnet capacity" of a furnace refers to which of the following?
• What is the specific gravity range of LP gas?
• How do outdoor temperature and humidity affect refrigerant properties?
• The vent system for a condensing furnace is classified as ______ by the National Field Gas Code.
• What is the primary benefit of conducting annual maintenance checks on HVAC systems?
• Why is maintaining proper evaporator coil temperatures important?
• What is the function of a condensate drain line?
• The reason heating thermostats have anticipators is to:
• Which gas is primarily indicated for use in residential heating?
• How does a variable speed blower enhance HVAC performance?