Exam 55: Heating and Air Conditioning Diagnosis and Service

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?

Toyota recommends the use of leak-detecting dyes.

Describe the purpose of the evacuation process.

When evacuating an A/C system, the vacuum pump should remain on and connected to the system for at least 30 minutes after reaching _____ inches of mercury (in. Hg).

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

Technician A always wears safety glasses when working on air-conditioning systems. Technician B makes sure there are no open flames in the area prior to working on the A/C system. Who is correct?

Technician A says the cabin air filter should be replaced every 12,000 to 15,000 miles (19,300 to 24,140 km)or once a year. Technician B says some cabin air filters have a charcoal layer for odor absorption. Who is correct?

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

Which statement best defines the term evacuation?

When an orifice tube A/C system has remained open for any length of time, the ____________________ should be replaced.

A compressor clutch that chatters when the A/C is off could be caused by _____.

Which does not cause excessive heat?

Technician A says the oil level of the compressor should be checked every year. Technician B says the system should be charged only after it has been completely evacuated. Who is correct?

Why must the work area be well ventilated when working on refrigeration systems?

Technician A says evacuating (pumping down)an air-conditioning system removes air and moisture from the system. Technician B says evacuating (pumping down)an air-conditioning system must be done anytime the system has been opened for repairs. Who is correct?

During a performance test, both the low-side and high-side pressures are below normal. What would cause this problem?

EPA certification is required to purchase R-12.

Which statement about orifice tube systems is false?

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

Refrigerant is lighter than oxygen.