Nate Heat Pump Test Exam with Verified Answers The three processes that transfer heat energy are conduction, convection and ________ a. Concentration. b. Radiation. c. Refraction. d. Static pressure. - CORRECT ANSWER -Radiation Which of the following factors affects a customer's level of comfort? a. Air movement. b. Humidity. c. Temperature. d. All of the above. - CORRECT ANSWER -All of the above A cooling load calculation estimates the sensible heat gain of a structure. The maximum sensible capacity of a cooling -only system should be within ______% of the calculated value. a. ± 10% b. + 10% c. + 15% d. + 30 % - CORRECT ANSWER -+ 15% The maximum sensible cooling capacity of a heat pump should be within _____% of the calculated sensible heat gain of the structure with a large heating load. a. ± 10% b. + 15% c. - 25% d. + 25% - CORRECT ANSWER -+ 25% The combined output of a heat pump and its auxiliary heat should not exceed the calculated heat loss of a home by more than _____. a. 10% b. 15% c. 20% d. 25% - CORRECT ANSWER -15% What amount of auxiliary electric heat is needed when the output of a heat pump on a design day is 18,800 Btuh and the heat loss of the home is 29,700 Btuh? a. 2.1 kWh. b. 3.2 kWh. c. 5.0 kWh. d. 10.9 kWh. - CORRECT ANSWER -3.2 kWh What effect does raising the pressure in a sealed system have on refrigerant? a. It becomes difficult to subcool the liquid refrigerant. b. It becomes more difficult to superheat the refrigerant vapor. c. The refrigerant's boiling point decreases. d. The refrigerant's boiling point increases. - CORRECT ANSWER -The refrigerant's boiling point increases What is the primary danger to people near an accidental refrigerant release or spill? a. Blurred vision caused by the refrigerant vapor coming in contact with the eyes. b. Changes in weather patterns caused by global warming. c. Damage to the food chain caused by decreased ozone levels in the stratosphere. d. Suffocation caused by the heavier refrigerant displacing the oxygen in the air. - CORRECT ANSWER -Suffocation caused by the heavier refrigerant displacing the oxygen in the air The maximum temperature at which refrigerant may be stored is _______°F when the container is no more than ____% full of liquid. a. 120°F 60% b. 125°F 60% c. 125°F 80% d. 135°F 80% - CORRECT ANSWER -125°F 80% Boiling of refrigerant occurs in which system component? a. Compressor. b. Condenser. c. Evaporator. d. Metering device. - CORRECT ANSWER -Evaporator Why is superheat necessary in a system that utilizes hermetic compressors? a. It insures that dry vapor reaches the compressor so that mechanical damage does not occur. b. It increases system capacity significantly. c. It prevents liquid refrigerant from gassing the metering device. d. Superheat is necessary only when open compressors are being used. - CORRECT ANSWER -It insures that dry vapor reaches the compressor so that mechanical damage does not occur. When the heat load on an evaporator increases, what is the effect on the system? a. Suction pressure decreases and discharge pressure increases. b. Suction pressure increases and discharge pressure decreases. c. Suction pressure and discharge pressure both decrease. d. Suction pressure and discharge pressure both increase. - CORRECT ANSWER -
Suction pressure and discharge pressure both increase What type of energy is transferred when work is done in the condenser? a. Latent heat energy. b. Sensible heat energy. c. Both latent and sensible heat energy. d. Neither latent nor sensible heat energy. - CORRECT ANSWER -Both latent and sensible heat energy What is the primary function preformed by the thermal expansion valve? a. It maintains the correct superheat in the hot vapor leaving the compressor. b. It maintains the correct superheat in the suction vapor leaving the evaporator. c. It maintains the proper subcooling level in the liquid refrigerant. d. It prevents flash vapor bubbles from developing in refrigerant entering the evaporator. - CORRECT ANSWER -It maintains the correct superheat in the suction vapor leaving the evaporator Which component pumps the refrigerant through the system and raises the vapor temperature? a. Accumulator. b. Compressor. c. Condenser. d. Evaporator. - CORRECT ANSWER -Compressor How are hermetic compressor motors cooled? a. Air drawn around the compressor shell by the condenser fan. b. With water circulated through tubing wrapped around the compressor shell. c. With suction vapor drawn from the evaporator. d. With a combination of air and water. - CORRECT ANSWER -With suction vapor drawn from the evaporator.
Suction pressure and discharge pressure both increase What type of energy is transferred when work is done in the condenser? a. Latent heat energy. b. Sensible heat energy. c. Both latent and sensible heat energy. d. Neither latent nor sensible heat energy. - CORRECT ANSWER -Both latent and sensible heat energy What is the primary function preformed by the thermal expansion valve? a. It maintains the correct superheat in the hot vapor leaving the compressor. b. It maintains the correct superheat in the suction vapor leaving the evaporator. c. It maintains the proper subcooling level in the liquid refrigerant. d. It prevents flash vapor bubbles from developing in refrigerant entering the evaporator. - CORRECT ANSWER -It maintains the correct superheat in the suction vapor leaving the evaporator Which component pumps the refrigerant through the system and raises the vapor temperature? a. Accumulator. b. Compressor. c. Condenser. d. Evaporator. - CORRECT ANSWER -Compressor How are hermetic compressor motors cooled? a. Air drawn around the compressor shell by the condenser fan. b. With water circulated through tubing wrapped around the compressor shell. c. With suction vapor drawn from the evaporator. d. With a combination of air and water. - CORRECT ANSWER -With suction vapor drawn from the evaporator.
