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NATE HVAC Certification Exam 2025
Prep- Air Conditioning & Heat Pump —
Complete Q&A Study Guide (Verified
Questions & Answers)
b (listen to the customer first, then ask questions) - CORRECT ANSWER When you arrive at a service call and meet the customer, you should ____. a. ask questions first, then listen to what the customer has to say b. listen to the customer first, then ask questions c. avoid discussion with the customer d. remind the customer that you are the professional and get on with your work b (1,600 ft3) - CORRECT ANSWER What is the volume of a room that measures 10 ft by 20 ft with an 8-ft ceiling? a. 800 ft b. 1,600 ft c. 2,400 ft d. 3,200 ft b (1,200 CFM) - CORRECT ANSWER What is the CFM requirements for an 1,800-ft2 house with 8-ft ceilings, if five air changes per hour are needed? a. 400 CFM b. 1,200 CFM c. 1,600 CFM
d. 2,400 CFM c (1,600 CFM) - CORRECT ANSWER What is the CFM requirement for an 2,400-ft2 house with 8-ft ceilings, if five air changes per hour are needed? a. 400 CFM b. 1,200 CFM c. 1,600 CFM d. 2,400 CFM a (79 in2) - CORRECT ANSWER What is the cross-sectional area of a 10 - in round metal duct? a. 79 in b. 200 in c. 314 in d. 418 in Note: Area of a circle = π x radius^ d (1,800 ft/min) - CORRECT ANSWER How fast does air with a velocity pressure of 0.20 in. w.g. move through a round duct? a. 400 ft/min b. 1,200 ft/min c. 1,600 ft/min d. 1,800 ft/min Note: Velocity = 4005 x (the square root of velocity pressure) d (1,800 ft/min) - CORRECT ANSWER How fast does air with a velocity pressure of 0.20 in w.g. move through a square duct?
c. It produces a clean, square cut d. All of the above a (soft drawn copper) - CORRECT ANSWER Spring-type benders may be used on ____. a. soft drawn copper b. hard drawn copper c. all copper pipe d. steel pipe a (make a mechanical joint in tubing) - CORRECT ANSWER A flaring tool is used to ____. a. make a mechanical joint in tubing b. measure pipe diameters c. remove burrs from piping d. solder tubing without the use of coupling d (solder tubing without the use of couplings) - CORRECT ANSWER A swaging tool is used to ____. a. cut copper tubing b. make a mechanical joint in tubing c. remove burrs from piping d. solder tubing without the use of couplings a (It is very accurate) - CORRECT ANSWER What is one of the advantages of a glass-stem thermometer? a. It is very accurate b. It is very durable c. It comes with a digital readout
d. Non of the above b (dry-bulb) - CORRECT ANSWER In discussing human comfort, the temperature most commonly referred to is ____. a. dew point b. dry-bulb c. wet-bulb d. Fahrenheit d (wet-bulb) - CORRECT ANSWER A sling psychrometer uses two glass-stem thermometers. One measures dry-bulb, and the other measures ____. a. dew point b. enthalpy c. relative humidity d. wet-bulb b (Bourdon tube) - CORRECT ANSWER A standard refrigeration manifold uses what type of element to measure pressure? a. Bellows b. Bourdon tube c. Diaphragm d. Spring c (30 in. Hg to 350 psig) - CORRECT ANSWER What is the pressure range of a standard compound gauge on a refrigerant manifold? a. 0 to 350 psig b. 0 to 500 psig c. 30 in. Hg to 350 psig
c. Reclaim machine d. Vacuum pump b (air velocity) - CORRECT ANSWER An anemometer uses a small fan blade to measure ____. a. air pressure b. air velocity c. air volume d. static pressure c (No flux is required) - CORRECT ANSWER What is one of the advantages of using silver brazing rods for copper-tocopper joints? a. A lower melting temperature is required b. A propane torch is normally used c. No flux is required d. No nitrogen purge is needed d (all of the above) - CORRECT ANSWER "Housekeeping" includes ____. a. disposal of waste b. fire prevention and protection c. proper storage of materials d. all of the above b (Goggles) - CORRECT ANSWER What type of eye protection should you wear when drilling overhead? a. Face shield b. Goggles c. Side shields
d. Spectacles b (DOT) - CORRECT ANSWER What agency regulates cylinders and chemicals transported in a service vehicle? a. ASHRAE b. DOT c. EPA d. OSHA a (contain information about personal protective equipment) - CORRECT ANSWER Material safety data sheets ____. a. contain information about personal protective equipment b. do not provide recommendations regarding emergency procedures c. should be kept in a safe place off-site d. should be read after any chemical products have been used d (Never) - CORRECT ANSWER When should oxygen be used in a refrigeration system? a. To clear a restriction in the line b. To pressurize for leak-testing c. To purge lines for brazing d. Never c (Class A is an "ordinary" fire that involves the burning of wood, paper, or textile products, extinguishing agent: water. Class B is a fire that contains oil, grease, paint, varnish, or other chemicals, extinguishing agent: foam. Class C is an electrical fire, extinguishing agent: carbon dioxide.) - CORRECT ANSWER Which of the following classifications of fire extinguishers should be used for electrical fires?
c (maintain three points of contact) - CORRECT ANSWER When using a ladder, you should always ____. a. extend the ladder 18 in. above the roof line b. face away from the ladder c. maintain three points of contact d. straddle the space between the ladder and a nearby object a (Disconnect and lock out power before starting unless testing requires the power to be on) - CORRECT ANSWER What is one of the most important safety precautions that you can take when working on electrical equipment? a. Disconnect and lock out power before starting unless testing requires the power to be on b. Keep one hand in your pocket while working on the power circuit c. Label all hot wires before starting d. Wear gloves suitable for high voltages a (When current travels through a ground path other than the neutral)
- CORRECT ANSWER When does a ground fault circuit interrupter open an electric circuit? a. When current travels through a ground path other than the neutral b. When the circuit is overloaded c. When there is a short circuit d. All of the above b (only by the person who installed the locks) - CORRECT ANSWER Proper lockout/tagout procedures state that locks placed on a lockout device may be removed ____. a. by anyone on the job site
b. only by the person who installed the locks c. only after all fuses have been replaced d. only when the equipment is grounded c (evaporation) - CORRECT ANSWER A natural cooling process produced by moisture on the skin changing to lowpressure steam is called ____. a. conduction b. convection c. evaporation d. radiation a (adding moisture) - CORRECT ANSWER During the heating season, human comfort can be enhanced without changing the temperature of the air by ____. a. adding moisture b. reducing moisture c. increasing air filtration d. increasing air speed a (completely closed) - CORRECT ANSWER During the cooling season, dampers on bypass humidifiers should be ____. a. completely closed b. completely open c. set at 25% d. set at 50% d (all of the above: liquid, solid, gas) - CORRECT ANSWER All matter can exist as a ____.
a. absolute b. latent c. sensible d. specific b (liquid, solid) - CORRECT ANSWER The latent heat of fusion is the amount of energy required to change 1 lb of a substance from the ____ phase to the ____ phase without changing its temperature. a. liquid, vapor b. liquid, solid c. solid, vapor d. vapor, liquid c (144 Btu) - CORRECT ANSWER At 32°F, 1 lb of ice can be changed to 1 lb of water by adding ____ Btu. a. 32 Btu b. 44 Btu c. 144 Btu d. 970 Btu d (970 Btu) - CORRECT ANSWER At 212°F, 1 lb of water can be changed to 1 lb of steam by adding ____ Btu. a. 32 Btu b. 44 Btu c. 144 Btu d. 970 Btu
a (saturated) - CORRECT ANSWER When liquid and vapor phases of a substance exist together, and no more liquid can vaporize without more energy being added, the vapor is said to be ____. a. saturated b. stabilized c. subcooled d. superheated d (superheat) - CORRECT ANSWER When a vapor is heated to a temperature higher than its saturation point, both the added heat and the temperature above saturation are called ____. a. latent heat b. sensible heat c. specific heat d. superheat b (evaporation) - CORRECT ANSWER The process of molecules escaping from the surface of a liquid is called ____. a. condensation b. evaporation c. saturation d. subcooling c (sublimation) - CORRECT ANSWER The process of a solid turning directly into a vapor without going through the liquid state is called ____. a. saturation b. subcooling
d. weight a (density) - CORRECT ANSWER Weight per unit volume or mass per unit of volume is called ____. a. density b. specific gravity c. specific mass d. specific volume d (specific volume) - CORRECT ANSWER Volume per unit of mass or weight is called ____. a. density b. specific gravity c. specific mass d. specific volume c (0.075 lb/ft3) - CORRECT ANSWER Under standard conditions, air weighs approximately ____ lb/ft3. a. 0.055 lb/ft b. 0.065 lb/ft c. 0.075 lb/ft d. 0.085 lb/ft d (86°) - CORRECT ANSWER Solve to find the Fahrenheit temperature corresponding to 30°C. a. 32° b. 68° c. 70° d. 86° Note: 32°F = 0°C. 9/5°F = 1°C.
°F = (9/5 x °C) + 32 °C = (°F - 32) x 5/ b (68°) - CORRECT ANSWER Solve to find the Fahrenheit temperature corresponding to 20°C. a. 32° b. 68° c. 70° d. 86° Note: 32°F = 0°C. 9/5°F = 1°C. °F = (9/5 x °C) + 32 °C = (°F - 32) x 5/ d (26.7°C) - CORRECT ANSWER Solve to find the Celsius temperature corresponding to 80°F. a. - 1.1°C b. 0.0°C c. 15.6°C d. 26.7°C Note: 32°F = 0°C. 9/5°F = 1°C. °F = (9/5 x °C) + 32 °C = (°F - 32) x 5/ c (15.6°C) - CORRECT ANSWER Solve to find the Celsius temperature corresponding to 60°F. a. - 1.1°C b. 0.0°C c. 15.6°C d. 26.7°C Note: 32°F = 0°C. 9/5°F = 1°C.
c (Dalton's) - CORRECT ANSWER The law that applies to the total pressure exerted by a mixture of gases or vapors is called ____ Law. a. Boyle's b. Charles' c. Dalton's d. Newton's d (6.28 x 10^18) - CORRECT ANSWER A coulomb is a charge of ____ electrons. a. 6. b. 628 c. 628 Million d. 6.28 x 10^ b (electron flow) - CORRECT ANSWER An ampere is a measurement of ____. a. electrical charge b. electron flow c. opposition to current d. potential energy b (force that moves electrons through a circuit) - CORRECT ANSWER Voltage is best described as the ____. a. amount of power being used in a circuit b. force that moves electrons through a circuit c. magnetic field surrounding a conductor d. resistance to the flow of electrons
b (resistance) - CORRECT ANSWER Current in a circuit is limited by ____. a. heat b. resistance c. temperature d. voltage a (conductor) - CORRECT ANSWER A substance that permits the free movement of electrons is called a(n) ____. a. conductor b. insulator c. resistor d. semiconductor c (A short, large-diameter conductor) - CORRECT ANSWER Which of the following conductors would have the least resistance? a. A long, large-diameter conductor b. A long, small-diameter conductor c. A short, large-diameter conductor d. A short, small-diameter conductor c (double) - CORRECT ANSWER If the voltage in a circuit is doubled and the resistance remains the same, the current will ____. a. drop to zero b. be cut in half c. double d. stay the same
