ASE A7 Heating Air Conditioning Practice Test

36. During a visual inspection an oily spot is found on a hose leading from the compressor. Technician A says there may be a refrigerant leak in the system. Technician B says today's R134a systems use mineral oil instead of the older R12 compatible PAG oil. Who is correct?

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

36.

Answer A is correct. Finding an oily spot on an A/C hose is a quick and easy way to spot a refrigerant leak. Closer inspection and testing will be necessary.

Answer B is wrong. Today's R134a air conditioning systems require PAG oil. Mineral oil is compatible with R12 refrigerant.

Answer C is wrong. Technician A is correct.

Answer D is wrong. Technician A is correct.

Snapshot of a scan tool display.

37. The inputs of a 134a refrigerant system in a passenger car are scanned. The display is shown above. Which of the following is correct?

  • A. The system has been overcharged with refrigerant.
  • B. The system has an undercharge.
  • C. The outside air temperature is preventing compressor clutch operation.
  • D. None of these statements are correct.

37.

Answer A is wrong. The system has an acceptable charge.

Answer B is wrong. The charge is sufficient.

Answer C is wrong. Most systems prevent compressor clutch operation when the temperature is in the thirties.

Answer D is correct. None of these are correct.

38. A refrigerant service station is used to recover, evacuate and recharge an air conditioning system. Technician A says the needle on the gauge should not increase and should remain steady after the recovery process is complete. Technician B says if the needle moves more than .01 inches of mercury after the evacuation process is complete, the system should be inspected for leaks. Who is correct?

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

38.

Answer A is wrong. The needle should remain steady after recovery. If there’s an increase in pressure it's likely there’s refrigerant left in the system.

Answer B is wrong. After the evacuation process is complete, the system is allowed to rest a specified amount of time. If the needle moves, the system should be inspected for leaks.

Answer C is correct. Both Technicians are correct.

Answer D is wrong. Both Technicians are correct.

39. A vehicle has poor air conditioning performance. The customer has added R134a refrigerant to the system. Technician A says to use a refrigerant identifier. Technician B says refrigerant mixtures are not recommended, but will not affect system pressures. Who is correct?

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

39.

Answer A is correct. Use a refrigerant identifier to identify R12, R134a, R22, hydrocarbons and air.

Answer B is wrong. This mixture increases the system's high pressure side, resulting in high head pressure. This causes premature compressor failure.

Answer C is wrong. Technician A is correct.

Answer D is wrong. Technician A is correct.

40. An air conditioner with an expansion valve performs poorly only during the hottest times of the day. Technician A says the receiver drier may be saturated. Technician B says there may be moisture in the refrigerant. Who is correct?

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

40.

Answer A is wrong. Both technicians are correct.

Answer B is wrong. Both technicians are correct.

Answer C is correct. The receiver drier contains a desiccant that must be changed after it's been exposed to moisture. If saturated with moisture, the excessive moisture in the drier will flow to the expansion valve and freeze, reducing system performance. Poor system performance is most noticeable during the hottest times of the day.

Answer D is wrong. Both technicians are correct.