NAPA Heating and Air Conditioning 5

Question 1

Under the Clean Air Act, what is required for a technician to service motor vehicle A/C systems for pay?

Accepted Answer

EPA Section 609 certification

Answer

Section 609 certification is required to service MVAC systems and buy small cans of refrigerant for professional use.

Question 2

What safety characteristic of R-1234yf requires special service equipment and procedures?

Accepted Answer

It is mildly flammable (A2L classification)

Answer

R-1234yf is classified A2L, mildly flammable, so equipment meeting SAE J2843 and unique fittings are required.

Question 3

On a hybrid vehicle with a high-voltage electric A/C compressor, why must the correct specified oil (often POE) be used?

Accepted Answer

Wrong oil can reduce electrical insulation and create a shock or failure risk

Answer

The oil contacts the motor windings, so conductive or incorrect oil can compromise high-voltage insulation.

Question 4

Why is a deep vacuum pulled on an A/C system after it has been opened for repair?

Accepted Answer

To remove air and boil off moisture at low pressure

Answer

Lowering pressure lowers water's boiling point so moisture vaporizes and is removed along with air.

Question 5

Which component should typically be replaced whenever an A/C system is opened for major repair or has been left open to the atmosphere?

Accepted Answer

Receiver-drier or accumulator

Answer

The desiccant in the drier or accumulator saturates with moisture and must be replaced to protect the system.

NAPA - National Automotive Parts Association Certified Mechanic Practice Test