NATE HVAC Certification Exam 2026/2027 –Verified Questions and Answers with Solutions | A+ Graded Practice Material

1 NATE HVAC Certification Exam 2026/2027 –Verified Questions and Answers with Solutions | A+ Graded Practice Material NATE HVAC CERTIFICATION EXAM Exam 2026 / 2027 Academic Year Q: Charging a heat pump with refrigerant is best accomplished in the _______ mode. A: Heating mode B: Cooling mode C: Defrost mode D: Emergency heating mode B: Cooling mode 2 Q: Heat pumps can provide both heating in the winter and cooling in the summer. In which mode is the heat pump more efficient? A: Heating mode B: Cooling mode C: Defrost mode D: Emergency heating mode A: Heating mode Q: Which of the following components is exclusive to the heat pump? A: Condenser B: Oil separator C: Reversing valve D: Accumulator C: Reversing valve 3 Q: Which of the following airflow rates is the most reasonable for a heat pump system operating in the heating cycle? A: 200 cfm per ton B: 300 cfm per ton C: 400 cfm per ton D: 450 cfm per ton D: 450 cfm per ton Q: During the heat pump's cooling cycle, the outdoor coil is utilized as a _________ while the indoor coil is utilized as a____________. A: Condenser, evaporator B: Evaporator, condenser C: Compressor, accumulator 4 D: Accumulator, condenser A: Condenser, evaporator Q: Heat is present in winter outdoor air until the outside air ambient temperature reaches a low temperature of: A: 0 degrees F B: 32 degrees F C: 273 degrees F D: -459 degrees F D: -459 degrees F Technically this is true, but not practical. A heat pump is doing good to continue to work below 10 deg F unless specifically designed for lower temperatures. 5 Q: The heat pump utilizes: A: Two filter-driers with check valves B: One bi-flow filter-drier C: A single mono-flow filter-drier in the liquid line D: Some use the bi-flow filter-drier and others use two filter-driers with check valves D: Some use the bi-flow- filter-drier and others use two filter-driers with check valves Q: The correct way to size a heat pump is to perform both heating and cooling load calculations and select the heat pump size by: A: Adding the heating load and cooling loads B: Subtracting the smaller load from the larger load C: Using the heating load to size the system D: Using the cooling load to size the system D: Using the cooling load to size the system 6 Auxiliary electric heat is necessary because: A: It provides heat for the home during defrosts B: It provides heat for the home in the event of a heat pump failure C: It provides heat for the home if the heat pump is unable to meet the demand for heat D: All of the above D: All of the above Q: Reading a voltage across the contacts of the outdoor thermostat means: A: The thermostat contacts are closed B: The thermostat contacts are open C: The thermostat contacts are stuck D: The thermostat contacts are working correctly B: The thermostat contacts are open 7 Q: Which of the following is not a type of heat pump? A: Ground to air B: Air to air C: Water to air D: Direct coupled D: Direct coupled Q: The coefficient of performance is determined by: A: Dividing the output btuh by the input btuh B: Dividing the input btuh by the output btuh C: Multiplying the input by the output D: Subtracting the output from the input B: Dividing the input btuh by the output btuh The coefficient of performance or COP of a heat pump, refrigerator or air conditioning system is 8 a ratio of useful heating or cooling provided to work required. Higher COPs equate to higher efficiency. Q: The "balance point" of a heat pump is: A: The lowest temperature at which the heat pump can meet the heating requirement for the structure B: The lowest temperature at which the heat pump can operate C: The temperature at which the heat pump has the highest efficiency D: The point at which the heating and cooling loads meet A: The lowest temperature at which the heat pump can meet the heating requirement for the structure Which of the following is an incorrect term for the solenoid valve that switches the heat pump between the heating and cooling modes? A: Changeover valve B: Reversing valve 9 C: Four-way valve D: Discharge operator valve D: Discharge operator valve The best location for the outdoor section of an air to air heat pump is: A: Where it gets the winter sun B: Where it is sheltered from the sun's radiation C: Where it never snows D: Under the shelter of a porch A: Where it gets the winter sun What may happen if the body of a reversing valve is slightly dented? A: Nothing, as they are made to be very durable B: The internal slide may stick C: The valve may make noises from the gas trying to pass through partially open ports 10 D: Both b and c are correct D: Both b and c are correct The reversing valve has 4 pipe connections. One pipe connection is on one side of the valve and three pipe connections are on the opposite side. What is the center connection on the side with three pipe connections? A: Compressor suction connection B: Compressor discharge connection C: Outdoor coil connection D: Indoor coil connection A: Compressor suction connection The reversing valve has 4 pipe connections. One pipe connection is on one side of the valve and three pipe connections are on the opposite side. What is the single connection on the side opposite the three connections? A: Compressor suction connection B: Compressor discharge connection C: Outdoor coil connection D: Indoor coil connection B: Compressor discharge connection 11 Why are reversing valves pilot operated? A: Because pilot operated valves use the differential pressure to operate the valve ports instead of having a solenoid valve working against the head pressure B: Because that is just the way they are made C: Pilot operated valves are quiet D: Heat pump reversing valves are NOT pilot operated! A: Because pilot operated valves use the differential pressure to operate the valve ports instead of having a solenoid valve working against the head pressure Two technicians are working on a heat pump system and are preparing to evacuate the system. Technician A says that in order to pull a good vacuum the reversing valve needs to be switched on and off during the evacuation so air and moisture are not trapped in the system. Technician B says technician A is incorrect and that the reversing valve will not switch with the system in a vacuum anyway. Who is correct? A: Technician A is correct B: Technician B is correct C: Both technicians A and B are correct D: Both technicians A and B are incorrect B: Technician B is correct 12 Terminal "O" on a heat pump thermostat is used for: A: Operating the reversing valve B: Operating the indoor fan motor C: Operating the compressor D: Operating the condenser fan motor A: Operating the reversing valve Terminal "G" on a heat pump thermostat is used for: A: Operating the reversing valve B: Operating the indoor fan motor C: Operating the compressor D: Operating the condenser fan motor B: Operating the indoor fan motor A typical 3 ton split system residential heat pump would have auxiliary electric heating elements 13 of about how many watts total? A: 4 kw B: 5 kw C: 15 to 20 kw D: 40 to 60 kw C: 15 to 20 kw One ton of heat is 12,000 BTU's By dividing the total BTU's of the unit by 3.414 (watts to btu's conversion factor) we get the total Watts. 36,000 BTU/3.14 = 10,545 watts needed minimum or 3,515 watts per ton. To make sure enough heat is available for the defrost cycle and temperatures below the systems balance point, it is suggested that 5 to 7.5 Kw be installed per ton. This standard makes the 15 to 20 kw the correct answer. Typical slide-in packages of electric heating elements come in units of how many kilowatts each? A: 1 to 2 kw 14 B: 3 to 6 kw C: 15 kw D: 25 kw B: 3 to 6 kw When a typical heat pump goes into defrost which of the following will occur? A: Compressor shuts off, reversing valve switches to cooling, defrost heaters energized and outdoor fan stops B: Compressor remains on, outdoor fan stops and auxiliary electric elements are energized C: Indoor and outdoor fans fun at higher speed, compressor remains on auxiliary and electric elements remain off D: Auxiliary electric elements operate at reduced voltage, compressor runs at half speed and outdoor fan shuts off B: Compressor remains on, outdoor fan stops, and auxiliary electric elements are energized What function does a Ranco E15 control serve? A: It is a common, combination time and temperature defrost control B: It is a mechanical defrost timer with a builtin thermostatic control 15 C: It is a defrost control that checks outdoor coil for frost buildup every 30, 45 or 90 minutes D: All of the above are correct D: All of the above are correct This control is all but obsolete Heat pumps often employ which of the following accessories? A: An accumulator B: Evaporator pressure regulator C: Electronic suction throttling valve D: Crankcase pressure regulator A: An accumulator Compressor crankcase heaters are used to: A: Help decrease refrigerant migration B: Reduce the potential of liquid flood-back 16 C: Reduce the potential of flooded starts D: Both a and c are correct D: Both a and c are correct A heat pump is operating in the heating mode. The lower the outside air temperature, the: A: More efficient the heat pump becomes B: Higher the SEER rating C: Higher the compression ratio D: Lower the balance point C: Higher the compression ratio Which of the following can prevent the reversing valve from changing positions? A: Low refrigerant charge B: Overcharge of refrigerant C: Air in the system 17 D: Low indoor airflow due to a dirty air filter A: Low refrigerant charge The supply air temperature on a normally operating heat pump is: A: Lower than that of a gas heating system B: Higher than that of a gas heating system C: About the same as that of a gas heating system D: Heat pumps do not use supply air A: Lower than that of a gas heating system When a heat pump is operating in the cooling mode, the suction line at the compressor should feel _____ and when operating in the heating mode the same suction line should feel _____. A: Cool, hot B: Hot, cool C: Hot, hot D: Cool, cool 18 D: Cool, cool High SEER rated heat pumps are those that employ: A: Scroll compressors and over-sized coils B: Reciprocating compressors and over-sized coils C: Scroll compressors and accumulators D: Reciprocating compressors and accumulators A: Scroll compressors and over-sized coils Which of the following metering devices can improve the operating efficiency of a heat pump? A: Thermostatic expansion valve B: Automatic expansion valve C: Fixed orifice D: Capillary tube A: Thermostatic expansion valve 19 During the defrost cycle the outdoor fan motor is: A: Shut down B: Operated at a reduced speed C: Stepped up to its highest speed D: Allowed to run at its normal speed A: Shut down Which of the following compressors is most "liquid slug" tolerable? A: Reciprocating B: Scroll C: Compliant scroll D: Rotary B: Scroll In the heating mode, ice can still collect on the outdoor coil even when the outside air 20 temperature is above 40 degrees. Why? A: Because the outside air temperature of 40 degrees still has a dew point temperature below the freezing point B: Because the outdoor coil is vaporizing refrigerant at a temperature below 32 degrees C: Because the latent heat of the refrigerant is always below freezing D: The statement is an incorrect statement B: Because the outdoor coil is vaporizing refrigerant at a temperature below 32 degrees The outdoor coil on a heat pump is defrosted using: A: Hot gas B: Electric heaters C: Off cycle defrost D: Straight time defrost A: Hot gas A customer is concerned that during the heating season heavy ice builds up on one side of the 21 concrete equipment pad and coil. The rest of the coil is clear of ice and the heat pump is meeting the heating needs of the house. What is most likely the cause of the problem? A: High winds on that side of the outdoor unit B: The outdoor unit is not level C: There is more refrigerant on that side of the coil D: A defrost problem exists B: The outdoor unit is not level SEER is an abbreviation for: A: Seasonal Energy Excellence Rating B: Seasonal Energy Efficiency Ratio C: Summer Energy Efficiency Ratio D: Special Efficiency Energy Rating B: Seasonal Energy Efficiency Ratio Typical residential split system heat pumps operate on how many voltages? A: One 22 B: Two C: Three D: Four C: Three The United States Department of Energy has mandated that the minimum allowable SEER rating for a new residential air conditioning system installation is: A: 11 SEER B: 12 SEER C: 13 SEER D: 14 SEER C: 13 SEER Which of the following actions will result in a decrease in volumetric efficiency? A: An increase in head pressure B: A decrease in head pressure 23 C: An increase in suction pressure D: Both a and c A: An increase in head pressure This is the ratio of the actual delivered gas volume to the swept volume or total displacement of the cylinder. The actual volume of gas inducted inside the cylinder for compression is less than the theoretical calculated volume because of the clearance volume. When the gas is compressed, and is delivered by the discharge valve, not all the gas is discharged since some volume of the gas remains inside the clearance volume at high discharge pressure. When the piston starts moving downwards, the suction valve does not opens immediately because of this high pressure gas. As the piston moves downwards the pressure of the gas in the clearance volume starts reducing due to expansion. Only when the pressure of this gas reaches to certain minimum level, the suction valve opens. Thus the portion of the suction stroke of the piston goes unused and during this certain volume of the refrigerant is not sucked. This reduces the volume of the refrigerant that can be sucked by the cylinder or the compressor. Read more: A heat pump operating in the cooling mode would be expected to have a return-to-supply air temperature differential in the range of: A: 5 to 6 degrees 24 B: 5 to 8 degrees C: 8 to 12 degrees D: 18 to 22 degrees D: 18 to 22 degrees A heat pump operating normally in the heating mode would be expected to have a supply air temperature in the range of: A: 70 to 80 degrees B: 80 to 90 degrees C: 85 to 105 degrees D: 100 to 130 degrees C: 85 to 105 degrees In any case, the compressor's discharge line temperature should not exceed what temperature? A: 175 degrees F 25 B: 200 degrees F C: 225 degrees F D: 350 degrees F C: 225 degrees F A heat pump defrosts even when there is no ice on the outside coil. Which of the following is most likely the problem? A: The defrost time clock is set for too short a cycle B: The outdoor coil is dirty and the system uses a pressure differential type of defrost initiation C: The sensing bulb of the defrost control is mounted too close to the bottom of the outdoor coil D: Each of these could cause the problem D: Each of these could cause the problem A technician places a heat pump into the auxiliary electric heating mode with the compressor de-energized. He measures a temperature rise between the return and supply air of 40 degrees. The measured voltage at the electric elements is exactly 222 volts and the measured amperage of the heaters is 60 amps. Using the equation CFM = BTU divided by 1.08 x TD, what is the CFM of the system? 26 A: 825 CFM B: 950 CFM C: 1055 CFM D: 1500 CFM C: 1055 CFM 222 x 60 = 13,320watts 13,320 / 1000 = 13.32 Kw btuh = 13.32 x 3415 = 45,488 cfm =((45,488 / (1.08 x 40)) cfm = 45,488 / 43.2 = 1052.95 Solid state defrost control boards can be adjusted to: A: Program the thermostat from outside the house B: Change the frequency of defrosts C: Control the speed of the outdoor fan during defrost D: Control the speed of the indoor fan during defrost B: Change the frequency of defrosts 27 A thermistor is an: A: Electronic temperature sensor that changes its resistance with changes in temperature B: Electronic pressure sensor that changes its resistance with changes in pressure C: Electromechanical thermostat used to terminate the defrost cycle when outdoor coil is clear of ice and frost D: None of these is correct A: Electronic temperature sensor that changes its resistance with changes in temperature Which component of a residential heating and cooling system heats or cools the home by moving heat? A) Gas furnace B) Air handler C) Heat pump D) Thermostat Answer: C) Heat pump Answer: C) Heat pump Explanation: The heat pump heats or cools the home by moving heat. It brings heat from outdoor air inside during the winter and takes heat from inside the home and releases it outdoors in the summer. 28 What is the purpose of the evaporator coil in a residential heating and cooling system? A) To filter the air B) To control the temperature C) To remove unwanted particles D) To absorb heat from the air Answer: D) To absorb heat from the air Answer: D) To absorb heat from the air Explanation: The evaporator coil absorbs heat from the air inside the home to keep it cool during the summer. It is located inside the air handler or attached to the furnace. Which component of the heating and cooling system manages the temperature inside the home? A) Gas furnace B) Air handler C) Thermostat D) Condensing unit Answer: C) Thermostat Explanation: The thermostat is responsible for managing the temperature inside the home. It is usually found on an inside wall and allows the owner to control the desired temperature. What is the purpose of the electrical panel in a heating and cooling system? A) To control the electrical current 29 B) To turn off power for maintenance C) To heat or cool the air D) To move air to different rooms Answer: A) To control the electrical current Explanation: The electrical panel controls the electrical current within the system. It is located on an interior wall and allows the technician to turn off power in various locations of the home for safe maintenance and service. Which type of wrench has a U-shaped opening to grip the face of a bolt or nut? A) Open-ended wrench B) Adjustable wrench C) Box-end wrenchD) Ratchet-type box wrench Answer: A) Open-ended wrench Explanation: Open-ended wrenches have a U-shaped opening to grip the face of a bolt or nut. They are widely used in HVAC work. Which tool is used to cut sheet metal when installing or repairing duct work? A) Claw hammer B) Wire strippers C) Aviation snips D) Tubing benders Answer: C) Aviation snips 30 Explanation: Aviation snips are used to cut sheet metal when installing or repairing duct work. They are designed specifically for this purpose. What is the purpose of a deburring tool? A) To cut plastic coating around wires B) To remove rough edges inside tubing C) To grip and turn rigid pipe fittings D) To bend tubes made from soft copper Answer: B) To remove rough edges inside tubing Explanation: A deburring tool is used to remove any rough edges inside tubing after a cut is made. It ensures a clean and smooth interior surface. Which tool is used to open the end of soft copper tubing for attachment to a flare-type fitting? A) Claw hammer B) Flaring tool C) Swaging tool D) Nut driver Answer: B) Flaring tool Explanation: A flaring tool is used to open the end of soft copper tubing so that it can be attached to a brass or steel flare-type fitting. It creates a flared end for a secure connection. 31 Which category of components in a residential heating and cooling system is responsible for warming or cooling the air? A) Air ducts B) Gas furnace C) Heat pump D) Supply ducts Answer: C) Heat pump Explanation: The heat pump in a residential heating and cooling system is responsible for warming or cooling the air by moving heat. It brings heat from outdoor air inside during the winter and takes heat from inside the home and releases it outdoors in the summer. What is the purpose of the evaporator coil in a residential heating and cooling system? A) To filter the air B) To control the temperature C) To absorb heat from the air D) To remove unwanted particles Answer: C) To absorb heat from the air Explanation: The evaporator coil in a residential heating and cooling system absorbs heat from the air inside the home to keep it cool during the summer. It is located inside the air handler or attached to the furnace. Which component of the heating and cooling system is responsible for managing the temperature inside the home? A) Gas furnace B) Air handler C) Thermostat D) Condensing unit Answer: C) Thermostat Explanation: The thermostat is responsible for managing the temperature inside the home. It is 32 usually found on an inside wall and allows the owner to control the desired temperature. What is the purpose of the electrical panel in a heating and cooling system? A) To control the electrical current B) To turn off power for maintenance C) To heat or cool the air D) To move air to different rooms Answer: A) To control the electrical current Explanation: The electrical panel in a heating and cooling system is responsible for controlling the electrical current within the system. It is located on an interior wall and allows the technician to turn off power in various locations of the home for safe maintenance and service. 1. Which type of wrench has an enclosed opening to grip the face of a bolt or nut? A) Open ended wrench B) Adjustable wrench C) Box-end wrench D) Ratchet-type box wrench Answer: C) Box-end wrench Explanation: Box-end wrenches have an enclosed opening to grip the face of a bolt or nut. They are often used in narrow spaces or on long studs. Which tool is commonly used to cut sheet metal when installing or repairing duct work? A) Claw hammer B) Wire strippers C) Aviation snips D) Tubing benders 33 Answer: C) Aviation snips Explanation: Aviation snips are used to cut sheet metal when installing or repairing duct work. They are specifically designed for this purpose. What is the purpose of a deburring tool? A) To cut plastic coating around wires B) To remove rough edges inside tubing C) To grip and turn rigid pipe fittings D) To bend tubes made from soft copper Answer: B) To remove rough edges inside tubing Explanation: A deburring tool is used to remove any rough edges inside tubing after a cut is made. It ensures a clean and smooth interior surface. Which tool is used to open the end of soft copper tubing for attachment to a flare-type fitting? A) Claw hammer B) Flaring tool C) Swaging tool D) Nut driver Answer: B) Flaring tool Explanation: A flaring tool is used to open the end of soft copper tubing What is the purpose of using a ruler in HVAC measurements? a) To find the area and volume of components b) To determine the length of objects c) To calculate temperature readings d) To measure weight and mass Correct answer: b) To determine the length of objects Explanation: HVAC technicians use rulers to measure the length of objects or components they 34 are working with. This helps them gather accurate measurements for various calculations and installations. What is the commonly used measurement represented by Line B on the ruler? a) 1/8th of an inch b) 1/4th of an inch c) 1/16th of an inch d) 1/2 of an inch Correct answer: a) 1/8th of an inch Explanation: Line B on the ruler represents 2/16th What is sensible heat? a) Heat energy that produces a change in state b) Heat energy that can be measured with a thermometer c) Heat energy that flows through a substance d) Heat energy that is transferred by radiation Correct answer: b) Heat energy that can be measured with a thermometer Explanation: Sensible heat is the type of heat energy that can produce a temperature change when added to or taken away from a material. It can be measured using a thermometer. What is latent heat? a) Heat energy that produces a change in state b) Heat energy that can be measured with a thermometer c) Heat energy that flows through a substance d) Heat energy that is transferred by radiation Correct answer: a) Heat energy that produces a change in state Explanation: Latent heat is the type of heat energy that produces a change in state, such as solids 35 becoming liquids or liquids becoming gases. It is involved in the absorption and release of heat during changes in an HVAC system. Which type of heat transfer involves the movement of heat through a substance? a) Conduction b) Convection c) Radiation d) Insulation Correct answer: a) Conduction Explanation: Conduction is the type of heat transfer that involves the movement of heat through a substance by contact between particles. It occurs when heat flows through materials such as solids. What should an HVAC technician do if they encounter a safety concern or accident on the job? a) Ignore it and continue working b) Report it to their employer or supervisor c) Share it on social media d) Keep it to themselves Correct answer: b) Report it to their employer or supervisor Explanation: It is important for technicians to report any safety concerns or accidents to their employer or supervisor so that appropriate action can be taken to address the issue and ensure the safety of everyone involved. 36 What should technicians do to maintain a safe work environment? a) Store material and equipment properly b) Clean up and dispose of waste and debris c) Focus on fire prevention and protection d) All of the above Correct answer: d) All of the above Explanation: Technicians should maintain a safe work environment by properly storing material and equipment, cleaning up waste and debris, and focusing on fire prevention and protection. These measures help reduce the possibility of accidents and injuries on the job. Which type of fire requires a smothering agent, such as foam, to extinguish it? a) Class A fire b) Class B fire c) Class C fire d) Class D fire Correct answer: b) Class B fireExplanation: A Class B fire involves flammable liquids like oil, grease, paint, or varnish. To extinguish this type of fire, a smothering agent such as foam is required. Why is carbon dioxide used to fight electrical fires? a) It conducts electricity b) It damages equipment 37 c) It displaces oxygen in the air d) It reacts with flammable materials Correct answer: c) It displaces oxygen in the air Explanation: Carbon dioxide is used to fight electrical fires because it does not conduct electricity and is less likely to damage equipment. However, it displaces oxygen in the air, so it should not be used in cramped spaces to avoid suffocation. What are the common causes of injuries on the job site? a) Fatigue, slips, and falls b) Electrical shocks c) Chemical exposure d) Equipment malfunctions Correct answer: a) Fatigue, slips, and falls Explanation: Nearly half of all injuries on the job site are caused by fatigue, slips, and falls. Technicians should pay special attention when climbing ladders, crossing slippery floors, and working around moving machinery to prevent such accidents. What is the recommended action when working with electrical equipment? a) Touch bare electrical wires with caution b) Turn off power before making any changes c) Work on "hot" parts or lines only when experienced d) Stand on wet ground or floors Answer: b) Turn off power before making any changes 38 Explanation: The passage states that it is important to always turn off the power before doing any work, even if making small changes that require touching exposed terminals or wires. This is a crucial safety measure to avoid electrical hazards. What should you do if you encounter extension cords that are worn or frayed? a) Continue using them with caution b) Replace them immediately c) Use them only for low-power equipment d) Wrap them with electrical tape Answer: b) Replace them immediately Explanation: According to the text, extension cords that are worn or frayed should be immediately removed from service. Continuing to use damaged cords can pose a safety risk and should be avoided. What is the purpose of grounding in an electrical circuit or system? a) To protect against lightning strikes b) To prevent electric shocks c) To improve equipment performance d) To reduce energy consumption Answer: b) To prevent electric shocks Explanation: Grounding in an electrical circuit or system helps protect against electric shocks by providing a connection to the ground. It is an important safety measure to ensure that electrical equipment and conductors are safely grounded. 39 When using electrical tools with cords, what safety device should you connect them to? a) Power surge protector b) Voltage regulator c) Ground-fault circuit interrupter (GFCI) d) Circuit breaker Answer: c) Ground-fault circuit interrupter (GFCI) Explanation: The passage mentions that when using electrical tools with cords, it is recommended to connect them to a ground-fault circuit interrupter (GFCI). The GFCI is a safety device that disconnects the device from the power source in case of electrical shocks or faults. What are the three general types of hazards directly associated with electricity? a) Electric shock, burns, and blast b) Electric shock, tripping hazards, and falls c) Burns, chemical exposure, and noise pollution d) Burns, falls, and related accidents Answer: a) Electric shock, burns, and blast Explanation: The passage states that the three general types of hazards directly associated with electricity are electric shock, burns (including burns caused by electric arcs), and blast. These hazards can pose serious risks to individuals working with or around electrical equipment. Note: This quiz is based on the provided passage, and the answers and explanations are derived from the information given.