Exam 55: Air-Conditioning Diagnosis and Service

Electronic leak detectors are being discussed. Technician A checks for leaks with the engine off, the shop doors closed, and the overhead fans turned off. Technician B checks for leaks outdoors with the engine running. Who is correct?

The compressor on a vehicle has seized. Besides the new compressor, what other component should also be replaced?

All R-12 test hoses have a Schrader core depressor in them.

Technician A says all the refrigerant oil in the A/C system is contained inside the compressor. Technician B says the oil circulates throughout the entire A/C system and at any given moment each component holds a small amount of oil. Who is correct?

____________________ testing provides a measure of an air-conditioning system's operating efficiency.

Technician A stores recycled refrigerant in emptied new refrigerant tanks. Technician B stores recycled refrigerant in UL-approved containers. Who is correct?

Refrigerant is lighter than oxygen.

Technician A says the refrigerant oil container should not be opened until it is time to use it and should be capped immediately after use. Technician B says after the system has been opened, compressed air should be used to flush dirt, moisture, and old refrigerant oil out of the system. Who is correct?

A/C parts replacement is being discussed. Technician A says if the system has been open for more than two minutes, the entire system must be completely evacuated and a new accumulator must be installed. Technician B says if the compressor has internal damage the condenser may need to be flushed and the receiver/dryer or accumulator replaced. Who is correct?

What should you do if you suspect that an alternative refrigerant has been used in the A/C system?

The filling level of a refrigerant container should never exceed _____ percent of the container's gross weight rating.

In an R-134a system, pressure and performance testing are the only ways to identify low refrigerant levels.

What are the four types of air-conditioning system problems?

Identify three safety hazards to be aware of when working with refrigerant.

Leaks in the evaporator core are generally caused by the corrosive combination of ____________________ and refrigerant, which combine to form hydrochloric acid.

What device does a computer-controlled A/C system use to monitor system pressure?

The ____________________ is a test instrument used to check the coil of a compressor clutch.

A vehicle is being diagnosed for poor A/C performance. The engine is started, and when the system is set to MAX A/C, the compressor engages normally. When the temperature control knob is moved from hot to cool, only hot air blows out of the A/C outlets. Technician A says there is a problem with the air duct system or the controls. Technician B says the system is low on refrigerant. Who is correct?

Why must air be removed from the A/C system during servicing?

An R-12 to R-134a conversion procedure is being discussed. Technician A says leak-test the system and conduct a performance test prior to removing the R-12. Technician B says leak-test the system and conduct a performance test after charging the system with R-134a. Who is correct?