ASE ASE Heating & Air Conditioning

Question 1

Which refrigerant is currently mandated for use in most new US passenger vehicle air conditioning systems?

Accepted Answer

R-1234yf

Answer

R-1234yf has replaced R-134a as the mandated refrigerant in most new US vehicles due to its lower global warming potential.

Question 2

What component in an automotive A/C system separates liquid refrigerant from vapor before it enters the compressor?

Accepted Answer

Accumulator

Answer

The accumulator, located on the low side between the evaporator and compressor, stores excess liquid refrigerant to prevent compressor damage.

Question 3

A technician finds a vehicle's A/C blows cold air at highway speeds but warm at idle. What is the MOST likely cause?

Accepted Answer

Faulty condenser fan

Answer

A faulty condenser fan reduces airflow at idle when ram air is absent, preventing proper heat dissipation and causing warm A/C output.

Question 4

What does superheat measurement indicate during an A/C system diagnosis?

Accepted Answer

Amount of refrigerant vapor above its boiling point at the evaporator outlet

Answer

Superheat is the temperature rise of refrigerant vapor above its saturation point at the evaporator outlet, used to verify proper evaporator flooding.

Question 5

When recovering refrigerant from an A/C system, a technician must use EPA-certified equipment per which regulation?

Accepted Answer

EPA Section 608

Answer

EPA Section 608 of the Clean Air Act requires certified recovery equipment to prevent venting of refrigerants to the atmosphere.

ASE Practice Test

ASE Practice Test

ASE ASE Heating & Air Conditioning