ASE A7 Heating Air Conditioning Practice Test

46. During a performance test on a CCOT A/C system, the manifold gauge set indicates that the low side pressure is high and the high side pressure is low. These test results indicate:

  • A. A frozen expansion valve.
  • B. A bad compressor.
  • C. A restricted condenser.
  • D. A clogged receiver drier.

46.

Answer A is wrong. The thermostatic expansion valve meters refrigerant in TXV air conditioning systems. A CCOT (cycling clutch orifice tube) system has a fixed orifice tube that meters a fixed amount of refrigerant.

Answer B is correct. A high low side and a low high side indicates a faulty A/C compressor, whether it is a CCOT (cycling clutch orifice tube) or a TXV (thermostatic expansion valve) system.

Answer C is wrong. A restricted or clogged condenser produces high discharge pressure.

Answer D is wrong. A receiver drier cleans and removes moisture from the refrigerant in TXV thermostatic expansion valve systems.

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47. A vehicle's passenger heating system is set to MAX HEAT but blows warm air only. All of the following will cause this condition EXCEPT:

  • A. An air pocket in the heater core.
  • B. A restricted heater control valve.
  • C. A weak engine cooling fan motor.
  • D. A clogged heater core.

47.

Answer A is wrong. An air pocket in the heater core reduces performance and results in a gurgling sound under the dash.

Answer B is wrong. A restricted heater control valve results in low heater performance.

Answer C is correct. A weak engine cooling fan motor results in engine overheating and poor air conditioning performance.

Answer D is wrong. A clogged heater core blocks flow, affecting the system's performance.

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48. The fixed orifice tube is removed from the high side of a CCOT air conditioning system. Metal debris is clogging the inlet screen. This metal debris is MOST likely caused by:

  • A. A ruptured desiccant bag.
  • B. The evaporator core.
  • C. A worn compressor.
  • D. The condenser.

48.

Answer A is wrong. Gummy or gooey debris in the orifice tube's inlet filter is usually a ruptured desiccant bag inside the accumulator.

Answer B is wrong. The evaporator core is not likely causing the metal debris.

Answer C is correct. Metal debris in the orifice tube's inlet filter is most likely caused by compressor wear.

Answer D is wrong. The condenser is not likely to cause metal debris. Flush the system and replace any faulty components.

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49. Technician A says an expansion valve reduces refrigerant pressure as it enters the evaporator core. Technician B says the expansion valve is fastened to the inlet port of the evaporator core. Who is correct?

  • A. Technician A
  • B. Technician B
  • C. Both A and B
  • D. Neither A or B

49.

Answer A is wrong. There are two types of metering devices used in today's vehicles: the (TXV) thermostatic expansion valve and the (FOT) fixed orifice tube.

Answer B is wrong. An externally equalized expansion valve is fastened to the inlet port of the evaporator, and the sensing bulb is fastened to the outlet port.

Answer C is correct. Both technicians are correct.

Answer D is wrong. The gas inside the sensing bulb expands as the temperature increases, causing the diaphragm to move a pintle, allowing refrigerant to enter the evaporator.

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50. Technician A says evacuating an air conditioning system will remove air, debris, and moisture. Technician B says to evacuate the system whenever it's been exposed to the atmosphere. Who is correct?

  • A. Technician A
  • B. Technician B
  • C. Both A and B
  • D. Neither A or B

50.

Answer A is wrong. Evacuating a system will remove moisture. Flushing the system will remove debris and metal.

Answer B is correct. Always evacuate the system if exposed to the atmosphere.

Answer C is wrong. Technician B is correct.

Answer D is wrong. Technician B is correct.

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ASE A7 Heating Air Conditioning Quiz
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