ASE ASE Heating & Air Conditioning 3

Question 1

What is the purpose of the receiver-drier in an A/C system that uses a thermal expansion valve (TXV)?

Accepted Answer

Stores liquid refrigerant and absorbs moisture with desiccant

Answer

The receiver-drier stores excess liquid refrigerant, filters debris, and uses a desiccant bag to absorb moisture that could damage the system.

Question 2

When performing an A/C performance test, the technician should check the temperature differential between which two points?

Accepted Answer

Center dash vent outlet and ambient air

Answer

A properly functioning A/C system should produce air at the center dash vent that is 35–45°F cooler than the measured ambient temperature.

Question 3

What does a low high-side pressure and a low low-side pressure indicate in an A/C system?

Accepted Answer

Refrigerant undercharge

Answer

Both pressures being low simultaneously is the classic symptom of an undercharged system due to refrigerant loss from a leak.

Question 4

Which type of blower motor speed control uses a variable resistance to reduce voltage to the motor at lower speed settings?

Accepted Answer

Resistor block

Answer

A blower motor resistor block drops voltage by adding resistance in series with the motor, reducing speed at lower fan settings.

Question 5

What is the MOST common cause of A/C system contamination that requires flushing the entire system?

Accepted Answer

Compressor failure that sends metallic debris through the system

Answer

A failed compressor can scatter metal particles throughout the A/C system, requiring complete flushing to prevent new component damage.

ASE Practice Test