A Answer A is correct. A leak in an A/C hose is usually indicated by an oily spot on the hose.

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

C Answer C is wrong. Technician A is correct.

D Answer D is wrong. Technician A is correct.

A Answer A is wrong. A stuck open expansion valve can freeze the suction line and may damage the compressor.

B Answer B is wrong. A low refrigerant charge would likely leave the line warm to the touch.

C Answer C is wrong. A stuck closed expansion valve would leave the hose warm to the touch and may draw the system into a vacuum.

D Answer D is correct. This is a normal condition.

A Answer A is wrong. The accumulator is located on the low side of the system..

B Answer B is wrong. It prevents excess liquid from entering the compressor.

C Answer C is wrong. It contains a desiccant designed to absorb any moisture in the system.

D Answer D is correct. An accumulator is used on a CCOT or Cycling Clutch Orifice Tube type system.

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

B Answer B is wrong. This mixture increases the systems high pressure side resulting in high head pressure. This causes premature A/C compressor failure.

C Answer C is wrong. Technician A is correct.

D Answer D is wrong. Technician A is correct.

A Answer A is wrong. Both technicians are correct.

B Answer B is wrong. Both technicians are correct.

C Answer C is correct. The receiver drier contains a desiccant that must be changed after it has been exposed to moisture. Moisture will freeze in the expansion valve reducing system performance.

D Answer D is wrong. Both technicians are correct.