First-Year HVAC Service Certification Practice Test

These questions are part of the practice quiz. Start practicing

• When checking the input BTUs of a gas appliance, which tool is primarily used?
• What formula is used to calculate a capacitor's microfarads under load?
• What does SPST stand for in relation to electrical switches?
• Resistance is defined as?
• According to OSHA regulations, how far above the roofline must an extension ladder extend?
• What does the term BTU stand for?
• What is the minimum required superheat typically for a refrigerant circuit?
• What distinguishes an induced draft system from a forced draft system?
• What could cause high pressure in a refrigeration system?
• What are the three types of combustion?
• What unit is used to measure electrical resistance?
• What happens to the density of air as it is heated?
• What are the three types of ignition systems?
• What is stratification in fluid dynamics?
• On a single phase compressor, how are the terminals labeled?
• What aspect does a compound gauge measure?
• Which of the following statements is correct about the nitrogen sweep process?
• What type of heat transfer occurs with no physical contact?
• Which component is found on a heat pump but not on an AC unit?
• How is dry bulb temperature measured?
• What should be done prior to connecting a regulator to a tank?
• How do you calculate actual subcooling in a refrigerant system?
• When brazing copper to copper, how can you visually identify that the copper is at the correct temperature?
• What unit is used to measure pressure on the low side/suction side of an MGA?
• The cut-off plate is a component of which part of the HVAC system?
• What temperature range is the high-limit cut-out often set between?
• What is the formula for calculating BTUs based on airflow?
• In refrigerant systems, which component is essential for converting refrigerant gas back into liquid?
• A cooling anticipator is also known as what type of anticipator?
• In HVAC terminology, how does one ton of air conditioning relate to CFM?
• What is the function of a heat anticipator in a thermostat?
• How many watts are equivalent to one horsepower?
• A good thermocouple should read approximately how many millivolts on a D.C. meter?
• The automatic expansion valve is designed to maintain what?
• When checking the windings on a compressor, what do readings of R to C = ∞ and S to C = ∞ suggest?
• What should you wear when handling refrigerants to ensure safety?
• What happens if a reversing valve fails?
• What scale should you set your meter on to measure a standing pilot?
• How is the area in square feet of a duct calculated from its dimensions in inches?
• What does CFM measure in an HVAC system?
• What is the correct order for the functions of a condenser?
• What type of connectors is specified to minimize noise and vibrations in ductwork?
• Which of the following is NOT a type of compressor?
• Joining PVC is a 3 step process which includes what?
• What does convection refer to in the context of heat transfer?
• How is Direct Current (DC) best described?
• On a 410A system, what is your superheat if you have a suction line pressure of 140 psig and a line temperature of 60°?
• What effect does increased humidity have on perceived temperature?
• What component is typically characterized by being bolted together for repairs?
• What happens to the boiling point of water as elevation increases?
• What is a primary function of a heat exchanger in HVAC systems?
• What is the square footage of a 4ft x 6ft space?
• In a heat pump line set during a cooling cycle, which tube is the suction line?
• What formula is used to calculate Sub Cooling?
• How many BTUs does a 25 kW heater produce?
• Which is an error that can occur in a combustion process?
• What is the wattage equivalent of one kilowatt?
• What is static pressure defined as?
• Low suction pressure in an HVAC system can be caused by which of the following?
• The main function of a GFCI circuit breaker is to:
• How is wet bulb temperature measured?
• When does a capillary tube metering device need cutting?
• What is the term for the small amount of refrigerant released when connecting and venting an MGA?
• What is the sensible heat formula for electric heat?
• Where should the probes be placed to take an external static pressure reading in relation to a furnace?
• What term describes air that leaks into a structure?
• How do you calculate the required superheat based on indoor and outdoor temperatures?
• When charging a refrigerant system, in what state should the refrigerant be added?
• What is the maximum allowable voltage imbalance between any leg of a 3-phase power supply?
• What meter scale should be set to measure flame rectification?
• What is the maximum temperature the hot gas discharge line from the compressor should not exceed?
• Amperage measures what aspect of electrical flow?
• True or false: A loose wire connection can cause lower than normal amperage in an HVAC system.
• How far must burners and ignition be located above the floor in a garage installation of a gas furnace?
• What does measuring voltage actually indicate?
• Which tool is commonly used to measure gas pressure?
• Which hose color is designated for the high side on an MGA?
• In HVAC systems, why is it important to check the motor windings?
• What does superheat refer to in HVAC systems?
• What is the BTU output of a 60kw electric heater?
• What functions does flux serve during soldering processes?
• Which type of joint would require a flux when brazing?
• To check motor windings with an analog meter, what scale should you set?
• What is an important factor to check if a dirty filter is suspected in an HVAC system?
• If static pressure in a duct is 1.10" w.c. and velocity pressure is 0.11" w.c., what is the total pressure?
• What are the two sides of a transformer called?
• An orange flame could be an indication of what?
• At what level should the gas ballast be closed when evacuating a refrigerant system?
• What is the definition of subcooling?
• True or False: A potential relay is used with a run capacitor to remove the capacitor from the circuit after the motor starts.
• If capacitors of 10 mfd, 5 mfd, and 5 mfd are wired in series, what is the total capacitance in mfd?
• What is a key factor in determining required superheat?
• What dimensions are required to calculate cubic footage?
• What is one common reason for soot buildup in a gas furnace?
• In a refrigerant circuit, where is an accumulator typically located?
• True or False: Cleaning the tubing and fitting is unnecessary when brazing.
• What material is typically used for electric heating coils?
• What does proper charging of a refrigerant system ensure?
• What crucial component does the static pressure reading indicate in a duct system?
• Which component is found on a PSC motor that is typically absent on an ECM motor?
• What does the term "electromotive force" refer to?
• How do you calculate the basic area of a duct?
• What is the specific gravity of natural gas?
• Which type of evacuation method involves removing air and moisture from a refrigeration system in stages?
• When does a fan typically activate in a heating system?
• What is the recommended method for discharging a capacitor safely?
• True or False: A bypass humidifier must always be installed on the supply.
• How many venting categories are there for appliances?
• What is the role of the Anode in a diode?
• Which of the following is NOT one of the types of pressures found in a duct system?
• True or False: Oxygen can be used to check for leaks in a refrigerant system provided all refrigerant has been recovered.
• What is the minimum service access space required for an installed gas furnace?
• How many BTUs are there in a cubic foot of liquefied propane (LP)?
• What type of voltage is supplied to a flame sensor during the heating cycle?
• In HVAC terminology, what does CFM stand for?
• In a gas-fired furnace, what do yellow flames indicate?
• Which device is responsible for regulating the refrigerant flow in HVAC systems?
• Name the components in a refrigeration circuit, in order.
• If a transformer has a 120v primary, 24v secondary, and a VA rating of 40, what is the safe amp draw of the transformer?
• If a coil has an airflow of 1800 CFM and an EAT of 76° and LAT of 98°, what is the BTU output?
• Which type of motor mount is commonly used for most fractional HP motors in central electric furnaces?
• What scale should an analog meter be set to when checking a grounded motor?
• What is another name for the suction/low side gauge on a manifold gauge set?
• What is the minimum distance Type B vent pipe must be kept from combustible materials?
• What is the sensible heat formula?
• What is the purpose of a BTU measurement?
• What is the recommended indoor humidity level for homes?
• What is the middle pipe called on the side of a reversing valve that has three pipes?
• Which situation could lead to an improper operation of a furnace converted from natural gas to LP gas?
• What method can be used to amplify a low amperage reading with a clamp-on amp meter?
• How is a liquid line drier removed from the system?
• What is the recommended residential indoor relative humidity?
• Soldering is typically done at what maximum temperature?
• Which of these is an automatic metering device?
• How many BTUs are in one kilowatt?
• A GFCI circuit breaker is primarily designed to detect:
• What is a biproduct of incomplete combustion?
• For a direct vent gas-fired furnace, where is combustion air drawn from?
• What is created around a wire when an electrical current is applied?
• What is voltage a measure of?
• What is the term for the air that is mixed with gas for combustion?
• To prevent oxidation when brazing, what method should be employed?
• Which wires are used to check the fan circuit?
• What is another name for the evaporator fan wheel commonly referred to as?
• Is a fluxing agent required when soft soldering copper to copper?
• When brazing/soldering in the horizontal position, where should the filler material be applied first?
• What do terminal labels T1, T2, and T3 signify?
• What is NOT a type of metering device?
• What line is insulated in an air-cooled split system with a furnace?
• What is the acceptable voltage drop across the contacts of a contactor?
• What does the term 'condensing point' refer to in HVAC?
• In addition to R-32, what is another refrigerant intended to replace R-410A?
• What condition must be met to consider an HSI functioning properly?
• What is the primary purpose of a die in HVAC applications?
• What is the primary purpose of gas piping pitch?
• What is convection?
• Which refrigerant is mentioned with a system using a TXV?
• What is the primary purpose of using a recovery cylinder?
• What is the total resistance of a parallel circuit with resistances of 6 ohms, 14 ohms, 4 ohms, and 11 ohms?
• Using Ohm's law, how would one find the value of amps?
• What type of electrical current is used to measure flame rectification?
• What is the significance of using a resistor when discharging capacitors?
• What indicates an open start winding when testing compressor windings?
• In HVAC systems, how is manifold gas pressure expressed?
• What does saturation temperature indicate?
• What indicates a potential issue in a reversing valve when suction line temperatures differ by more than 5°?
• What is dew point?
• What are the two evacuation methods commonly used?
• Which of the following refrigerants is being introduced to replace R-410A?
• Heat added to the refrigerant in a vapor state after the evaporation process is called?
• What is the BTU output for a coil with an airflow of 21,000 CFM with an EAT of 67° and LAT of 84°?
• What is another term used to describe total heat?
• Which of the following is NOT a safety control used in an induced draft system?
• During a heating cycle on a heat pump, what is the smaller diameter tube referred to?
• When testing a refrigerant system for leaks, how is the maximum pressure determined?
• What does a bold dashed line indicate on a wiring diagram?
• What does the National Fuel Gas Code regulate?
• How do you test a hot surface ignitor (HSI)?
• Which type of compressor relies on the principle of centrifugal force?
• On an R-22 system, what is your subcooling if you have a liquid line pressure of 250 psig and a line temperature of 100°?
• What happens to the air pressure inside a duct when velocity pressure increases?
• What is the proper micron reading for complete evacuation in HVAC?
• What is the primary purpose of an accumulator in a refrigeration system?
• What is the primary purpose of adding heat to a vapor during superheating?
• What is the proper chemical name for natural gas?
• Which device is primarily used to test electrical components like motors and diodes?
• How do ACR and nominal tubing diameters differ?
• How many wires are typically connected to a standard thermostat?
• What is defined as heat that causes a change in temperature of a substance?
• What is the air composition percentage for other gases in the atmosphere?
• Name the heat rejection component in a refrigeration circuit.
• How many BTUs are present in one ton of air conditioning?
• How do you convert PSIG to PSIA?
• In electrical theory, what is the relationship between voltage, current, and resistance?
• What is the basic formula for calculating airflow?
• What is latent heat?
• According to Ohm's law, how can voltage be calculated?
• What is conduction?
• What is required when using a motor mount to ensure safety?
• Which materials are commonly used in modern hot surface ignitors (HSIs)?
• What can contribute to low suction pressure due to airflow problems?
• What is the calculated airflow in CFM for a duct measuring 24" x 18" at a velocity of 728 FPM?
• According to the national electrical code, what classification is used for thermostat wire?
• Which of the following are the three parts of an atom?
• A technician servicing an LP gas furnace notices large amounts of soot in the heat exchanger after it was converted from natural gas. What could be the cause?
• What are the two types of wiring diagrams?
• What is the name of the plate where the wires on a thermostat get attached?
• What is the primary component of the air we breathe?
• How does a dirty condenser coil affect system performance?
• What type of oil is commonly used to lubricate a motor?
• Which output is necessary to diagnose a gas furnace issue based on flame color?
• What is the target subcooling for a refrigerant system charged with R-410A?
• When a refrigerant system charged with R-22 has a suction pressure of 85 psig, what is the line temperature?
• On an SPST switch in the open position with 120VAC applied, what would the multimeter read across the switch?
• Which category of venting involves negative pressure more than 140 degrees above the dew point?
• When expanding (swaging) small diameter tubing, what precaution should be taken?
• For natural gas, what is the maximum allowable inlet gas pressure?
• Which of these describes a function of superheat?
• What is the cubic footage of a 4ft x 6ft x 8ft space?
• What part of the manifold is responsible for the gas flow?
• How is the capacity of a recovery cylinder determined?
• Which refrigerant is a new alternative to replace R-410A in HVAC systems?
• What does the abbreviation PSC stand for in HVAC terminology?
• In a refrigerant system with a fixed orifice, what indicates an undercharged system?
• What happens to air as it cools down?
• Should horizontal gas piping be pitched? If so, how much?
• What is the procedure to check the firing rate of a gas appliance?
• What is the formula derived from Ohm's Law to calculate Current?
• Which formula is used to calculate Super Heat?
• What does continuity from any terminal to copper tube indicate when checking compressor windings?
• What indicates an overcharged system in a refrigerant system?
• What is sensible heat characterized as?
• What is the required superheat calculated for the R-22 system?
• What might higher than normal suction pressure and lower than normal high side pressure indicate on a heat pump?
• What component helps regulate the flow of refrigerant in the system?
• When using air-acetylene, how is heat controlled?
• For two electric heaters each drawing 6.25 amps at 240v, what is their total BTU output?
• During a cooling cycle, what material typically makes up the larger diameter tube in a heat pump line set?
• What is the cooling capacity of a system rated at 12,000 BTU/hr?
• Which component would be used to connect the thermostat wires?
• What is the temperature difference (ΔT) used to calculate BTU if the EAT is 76° and the LAT is 98°?
• What is the purpose of a roll-out switch in HVAC systems?
• What is the formula for calculating the safe amp draw of a transformer?
• What would be the BTU output of an electric duct heater at 240VAC with a resistance of 12.77 Ohms?
• Is flux needed when brazing aluminum to aluminum using Lucas-Milhaupt Al-822?
• What formula represents the power triangle for calculating watts?
• What percentage of the air we breathe is composed of oxygen?
• With complete combustion, what should the flames look like?
• What does a complete combustion process require?
• Which statement correctly describes a hermetic compressor?
• What scale do you set your meter to measure flame rectification?
• What two parts make up a flaring tool kit?
• What is required to create a useful heat transfer when soft soldering?
• What wires do you need to jump to check the heating circuit?
• What are the three forms of heat transfer?
• Type B Vent pipe consists of which of the following?
• What is the larger diameter tube called during a heating cycle on a heat pump?
• Which tool is NOT suggested for cutting a capillary tube metering device?
• How can a fan be activated during the heating cycle?
• In terms of airflow, what does CFM stand for?
• Which connectors are used to secure sections of a rectangular sheet metal duct to the main supply line?
• What is the output power formula for electrical devices?
• Which device disconnects voltage to the gas valve if the furnace overheats?
• In HVAC terminology, what does the term 'infiltration' refer to specifically?
• If an SPST switch is closed and 120 VAC is applied, what should the multimeter read when placed across the switch?
• Which factor determines whether to use soldering or brazing?
• What is the specific gravity of liquefied propane (LP)?
• Which sequence correctly represents the order of steps in the vapor-compression process?
• What does the use of aluminum in Type B Vent pipe primarily provide?
• What was the actual subcooling calculated for the R-410A system?
• How is velocity pressure defined?
• The proper name of the tool used to cut the threads of a steel pipe is called a:
• In relation to an HVAC system, what does VPN stand for?
• What is the free area of a duct measuring 38" x 22" with a 1' liner?
• How is the label for the run terminal on a single phase compressor identified?
• According to Ohm's Law, what does the variable I represent?
• How can the volume of refrigerant in a recovery cylinder be determined if the volume is unknown?
• Which of the following statements about Type B Vent pipe is true?
• What is the single pipe called on a reversing valve?
• Which symptoms indicate bad compressor valves in a refrigerant circuit?
• Which part of a diode is responsible for allowing current flow?
• What does a thermostatic expansion valve aim to maintain?
• If a circuit has a resistance of 14 ohms and is supplied with 240v, what is the amp draw?
• How does radiation transfer heat?
• The formula for calculating amp draw in a circuit is based on which law?
• What factor can affect the performance of a bypass humidifier?
• What is a primary function of a diode?
• What is the method for calculating required superheat given indoor and outdoor temperatures?
• What essential safety measure must be taken when charging refrigerant into a system?
• What is the effect on high side pressure when compressor valves are malfunctioning?
• How is CFM calculated for air moving through a duct measuring 16" x 22" at a velocity of 1011 FPM?
• How many BTUs are equivalent to one watt?
• What is the allowable voltage variance for a furnace blower motor rated at 230 V?
• If a PT chart for a refrigerant has a Dew point and Bubble point associated with the refrigerant, which one should be used to charge for subcooling?
• Which of the following is NOT a part of the combustion triangle?
• What is the primary property of current in a diode?
• Do you need to use a flux when brazing copper to copper?
• How do you perform a temperature rise test in an HVAC system?
• What is the purpose of a liquid line drier?
• What color hose on an MGA is used for utility?
• How many CFM are in one ton of air conditioning?
• Which statement is true regarding the operation of an HVAC pressure switch?
• In HVAC systems, what is the primary function of a humidifier?
• If a refrigerant system has 4° subcooling when the target is 14°, what does that indicate?
• What is the definition of Alternating Current (AC)?
• What is the effect of a bad condenser motor?