ESCO Gas Furnace Practice Exam

These questions are part of the practice quiz. Start practicing

• What does the term "two-stage" in a gas furnace refer to?
• What does the term "draft" refer to in a gas furnace?
• How does ductwork condition affect furnace efficiency?
• What volume of flue gas is produced by a 60,000 BTU/H Category I fan-assisted natural gas furnace operating at 50% excess air?
• What is the function of an adjustable shutter on older burners?
• What can cause a gas furnace to short cycle?
• What is the minimum AFUE rating for typical condensing furnaces?
• To verify proper airflow range for a furnace, which method should a technician use?
• How is the effectiveness of a gas furnace's combustion typically assessed?
• What is the ignition temperature range of natural gas?
• In what situation might a technician recommend upgrading to a more efficient model?
• How can you identify a properly functioning pilot light?
• What is one common cause of a gas furnace igniting but not producing heat?
• What can a blinking light on the furnace control board signify?
• Which component in a furnace helps manage the combustion process by affecting the amount of gas used?
• What device is used to monitor temperature in a gas furnace?
• What is a furnace that can be installed in different configurations called?
• Which three elements must be present for combustion to occur?
• What is the term for the highest concentration of fuel at which the air/fuel mixture will ignite when exposed to an ignition source?
• Which rating is used to determine the efficiency of gas-burning appliances?
• To change the cubic feet per minute (CFM) delivered by a single-speed belt-driven blower, what should the technician adjust?
• What type of gas is commonly used in residential gas furnaces?
• Why is it important to maintain proper pressure in a heating system?
• A customer reports that their direct hot surface ignition furnace will not light despite the inducer motor running. What is likely the fault if 17 VAC is measured at the gas valve?
• What is a key function of the gas valve in a furnace?
• What is the function of the gas valve in a gas-burning furnace?
• What does a blocked air intake in a gas furnace lead to?
• What can be a result of poorly sealed ductwork?
• What is the purpose of a cross-lighter or carry over on a gas burner?
• What is the typical gas pressure required at the manifold and burners in natural gas furnaces?
• What might indicate that a gas furnace needs maintenance?
• What is the typical air temperature range for a mid-efficiency, category 1 gas furnace?
• In a gas furnace, what component is responsible for ensuring safe operation by detecting the burner flame?
• What physical sign may indicate that a furnace is experiencing a fault?
• How often should carbon monoxide detectors be tested in homes with gas furnaces?
• What should you do if you smell gas near your furnace?
• What defines a dedicated vent system?
• What is the purpose of the combustion chamber in a gas furnace?
• What is the proper pitch for the flue pipe when installing a category IV condensing furnace?
• What is a common indicator that a gas furnace requires servicing?
• What is the minimum distance Type-B vent pipe must be kept from combustion materials?
• What is the primary role of a pressure switch in a gas furnace?
• What should be ensured around a gas furnace during maintenance?
• What could happen if the burner and ignition sources of a gas furnace are installed too low?
• Why is there a delay in blower motor operation when a furnace’s burners are ignited?
• How is higher system efficiency achieved in a category IV condensing furnace?
• What is the proper instrument for determining the percentage of carbon dioxide in the flue gas of a gas burning furnace?
• What is uncontrolled air that leaks into the combustion area referred to as?
• What is a common symptom of flame rollout in a gas furnace?
• What is the function of the limit switch in a gas furnace?
• What is the name of the electronic control that is responsible for the overall function of a furnace?
• What should a technician do if a natural gas furnace is found to have a defective heat exchanger?
• How should a lockout/tagout procedure be managed during service?
• What is the recommended range for the manifold pressure in natural gas appliances?
• What type of draft is employed to move flue gas through the heat exchanger and into the venting system in modern gas-fired furnaces?
• What does the abbreviation "BTU" stand for?
• What does flashback indicate in a gas system?
• What effect does a malfunctioning thermocouple have on a gas furnace?
• What is the purpose of threading black iron pipe in gas installations?
• What are the two main types of gas furnaces?
• What should a technician check if a furnace makes a loud bang upon ignition?
• What might be indicated by a furnace that fails to produce heat?
• What is the maximum acceptable level of carbon monoxide (CO) in flue gas?
• When using an extension ladder to work on a rooftop unit, how far should it extend beyond the support point?
• When installing a Category IV, two-pipe vent system, the elbow for the combustion air intake should be positioned how?
• Which safety monitor must be engaged for the safe operation of a gas furnace?
• What is a characteristic of a direct ignition furnace?
• What can happen if the expansion tank fails?
• What is a common reason for adjusting the motor pulley size in a gas furnace?
• What is a significant advantage of using a condensing gas furnace?
• If the pressure switch is open and the inducer motor is running but the ignitor does not come on, what is the likely diagnosis?
• A standing pilot gas valve with 100% shut-off means what?
• Which signs may indicate that a gas furnace's heat exchanger is cracked?
• How much energy does burning one cubic foot of liquid petroleum (LP) gas produce?
• What is the typical manifold pressure for a liquefied petroleum (LP) gas appliance?
• Which factor might lead to inefficiencies in a gas furnace's operation?
• To check for an obstructed flue pipe on an induced draft furnace, a technician should use which tool?
• Which statement accurately reflects the behavior of nitrogen?
• Which gases are classified as liquefied petroleum gases?
• What is one consequence of maintaining a gas furnace with high humidity?
• What component is typically checked when troubleshooting a furnace that fails to ignite?
• The cut-off plate is a component of which part of the gas furnace?
• Why do heating thermostats have heat anticipators or cycle rate adjustments?
• What function does an integrated control in a furnace provide?
• What is the purpose of a draft inducer fan in high-efficiency furnaces?
• What type of maintenance is crucial for preventing carbon monoxide buildup?
• What is the primary purpose of the flue baffle in a furnace?
• What design feature lowers the pressure but increases the velocity of gas in a burner tube?
• According to OSHA, which of the following statements about confined spaces is correct?
• In a gas furnace equipped with an induced draft motor, which switch must function properly to continue the ignition sequence?
• What is the proper name of the tool used to cut the threads of a steel pipe?
• What does it indicate if an ohmmeter reads infinity between the high speed and common wires on a 120 VAC furnace fan motor?
• What is the typical vent stack temperature range for a natural draft furnace?
• Which type of connectors are used to control noise transmission through metal ductwork in residential installations?
• After assessing a gas valve that failed to open, which action should a technician take next?
• What is the potential risk associated with a gas furnace that is not properly maintained?
• When starting an intermittent spark ignition furnace, what might indicate a faulty component if the pilot flame lights but continues to spark after 90 seconds?
• What component in a furnace is responsible for ensuring airflow based on temperature settings?
• What is the operating voltage of a spark igniter?
• What is the specific gravity range of liquefied petroleum (LP) gas?
• What is the first step in troubleshooting a gas furnace that is not igniting?
• In a garage installation, at what height must the burner and ignition sources be located according to national standards?
• How do you determine the correct size of a gas furnace for a home?
• What is a common type of venting system used for gas furnaces?
• What is the construction characteristic of Type B vent pipe?
• What role does an expansion tank play in a heating system?
• If a technician finds soot in the heat exchanger of an LP gas furnace converted from natural gas, what likely caused this issue?
• What is the difference between a standing pilot and an intermittent pilot system?
• What is a primary cause of burner "flashback"?
• In a gas furnace, what is the starting point for maintaining safe operation regarding venting?
• What component controls the temperature of the gas entering the furnace?
• What is the consequence of poor airflow in a gas furnace system?
• What is one sign of poor furnace installation?
• What is the primary component of natural gas?
• Which instrument is used to check the gas pressure of a furnace?
• Where should pipe joint compound be applied?
• How can you increase the efficiency of an older gas furnace?
• What is likely to occur in a heating system without an expansion tank?
• Why is regular maintenance important for gas furnaces?
• What material is the helical shaft made of in a fan/limit switch that reacts to temperature changes?
• What feature does a condensing gas furnace include to enhance efficiency?
• Before testing the resistance of a hot surface ignitor with a digital multimeter, what should a technician do?
• What feature helps direct air for better combustion in gas furnaces?
• Which negative consequence results from an oversized furnace operating at low efficiency?
• What is the recommended external static pressure for a typical gas furnace blower system?
• When threading black iron pipe for a natural gas furnace, how many threads should typically be cut?
• What level of carbon monoxide exposure is considered dangerous for individuals?
• What is the recommended pitch for gas piping installation?
• What should be checked first if a furnace does not turn on?
• What types of motors are described as constant airflow, constant-torque, and constant-speed?
• Which issue could result from improper ventilation in a gas furnace?
• What maintenance should be performed on the air filter of a gas furnace?
• What common issue can arise from improper furnace maintenance?
• What factor contributes to excessive soot production in a furnace?
• What component senses room temperature and controls the furnace operation?
• If a technician reads zero Ohms between the common and low speed wires on a 120 VAC PSC furnace motor, what does this indicate?
• What is a function of redundant gas valves in gas furnaces?
• What is a common symptom of a stuck gas valve in a furnace?
• Which component is responsible for igniting the gas in a furnace?
• According to ASHRAE standards, what is the maximum allowable CO concentration in a living area?
• What is the importance of venting in gas furnace operation?
• What must be checked if a gas furnace fails to ignite properly?
• Which component prevents the heater from operating when airflow is inadequate?
• What primarily causes pressure drops in a natural gas piping system?
• If a technician observes wavering flames in one corner of the burner after startup, what could this indicate?
• What is the primary function of a gas furnace?
• What is a key indicator that a gas furnace needs to be replaced?
• What is the primary objective of a pressure switch in a gas furnace?
• What should be done immediately if a gas odor is detected near a gas furnace?
• What is a true statement about personal protective equipment (PPE)?
• What is the primary function of a blower motor in a gas furnace?
• What is the normal voltage for a hot surface igniter?
• What is the proper method of testing flame rectification?
• What might a technician suspect if flames "roll out" when the blower is energized in a standing pilot furnace?
• The correct orientation of a combustion air intake elbow in a two-pipe vent system is crucial for what reason?
• What does AFUE stand for and why is it important?
• The lowest concentration of fuel at which an air/fuel mixture will ignite is known as what?
• What are common types of gas connections for residential furnaces?
• If voltage is applied across two speed terminals on a fan motor, what will likely happen?
• Which component of the gas furnace does the blower housing house?
• What is the function of a combustion air vent?
• What is a common symptom of carbon monoxide poisoning?
• How much combustion air is required to burn and vent one cubic foot of natural gas?
• A furnace designed with the blower motor positioned beneath the heat exchanger is referred to as what type of furnace?
• Which component helps ensure proper gas flow to the burners?
• What material is best suited for connections in high-temperature applications within gas systems?
• If a furnace nameplate specifies a temperature rise of 40 to 70 degrees but measurements indicate a rise of 80 degrees, what should be done?
• Why is proper installation important for a gas furnace?
• Burning one cubic foot of natural gas will produce approximately how many BTUs?
• How often should a gas furnace be serviced for optimal performance?
• What is the primary function of the limit switch in a furnace?
• What is one possible cause of a gas furnace excessively cycling on and off?
• What symbol typically indicates a warning condition when monitoring a gas furnace?
• How can high humidity levels impact furnace performance?
• What is likely the outcome of using an oversized mid-efficiency furnace?
• What is the main benefit of having a hot surface ignitor in a gas furnace?
• What can high duct static pressure indicate in a heating system?
• The air that mixes with natural gas in the burner is referred to as what?
• What symptom might suggest a malfunctioning gas valve?
• Which of the following describes an ideal condition for the operation of a gas furnace?
• Which formula is used to calculate the CFM based on BTU/hr output?
• In a gas furnace, what might cause inconsistent heating?
• What basic maintenance can homeowners perform on their gas furnace?
• How does a programmable thermostat benefit gas furnace operation?
• What is a possible consequence of a malfunctioning pressure relief valve?
• What reading should a properly functioning thermocouple produce on a DC meter?
• What kind of contact do most thermostats contain to control the heating system in a conditioned space?
• A technician using a manometer on an induced draft furnace is most likely testing for what?
• In a gas furnace, what is the result of having a clogged flue pipe?
• What is the role of the thermocouple in a gas furnace?
• What happens when the limit switch of a gas furnace is triggered?
• What factor primarily determines the severity of an electrical shock?
• Why is it important to have an annual combustion analysis done on a gas furnace?
• What must be done if a furnace pilot light goes out frequently?
• What is the primary function of a blower delay relay in a gas furnace?
• What is the primary function of a fan/limit switch in a furnace?
• How does the condensation of water vapor in flue gas impact the efficiency of a furnace?
• What condition causes the temperature limit safety switch to shut off the burner?
• How much current does a typical flame sensor conduct?
• When should you consider installing a new thermostat with a gas furnace?
• What is the primary function of a gas valve in a furnace?
• How is the fan cycled during heating in a gas furnace that has an integrated furnace control (IFC)?
• What is the primary function of a "spud" or burner orifice?
• What serious condition can arise from a blocked flue in a gas furnace?
• What type of maintenance can help improve the efficiency of a gas furnace?
• What safety device is essential for preventing gas leaks in a furnace?
• What is the most common burner used in induced draft furnaces?
• What does the heat anticipator in a thermostat help to achieve?
• What is the role of a gas pressure regulator in a gas furnace?
• What symptoms may healthy adults experience when exposed to low concentrations of carbon monoxide?
• At what location should you adapt to a larger vent when venting Category I furnaces?
• What could be a sign of a blocked venting system in a gas furnace?
• What does "turning off the gas" refer to in furnace maintenance?
• If the ignitor in a hot surface ignition furnace does not energize after the inducer draft motor is engaged, what is the technician's next step?
• What category does the Natural Fuel Gas code classify a vent system for a condensing furnace?
• What is a furnace with the blower motor located above the heat exchanger called?
• What is the name of the first duct section that connects a furnace to the branch ducts?
• What is essential for maintaining safety during gas furnace repairs?
• Which component is primarily responsible for distributing heated air throughout the home?
• Which maintenance practice is essential for a gas furnace?
• What does a BTU measure in terms of heating?
• Which type of pilot system is known for being more energy-efficient?
• Which is a sign that a gas furnace may be inefficient?