Air Conditioning Repair Car Air Conditioning Repair 4

Question 1

Which electrical component engages and disengages the AC compressor on most conventional systems?

Accepted Answer

Electromagnetic clutch

Answer

The electromagnetic clutch magnetically couples the compressor pulley to the compressor shaft when energized, allowing the compressor to be driven by the serpentine belt only when needed.

Question 2

A manifold gauge shows high-side pressure of 350 psi and low-side pressure of 10 psi on a hot day. What does this pattern suggest?

Accepted Answer

Blocked orifice tube or expansion valve

Answer

Extremely high discharge pressure combined with very low suction pressure is a classic sign of a restriction (blockage) in the metering device, starving the evaporator of refrigerant.

Question 3

What is the correct procedure for adding refrigerant to a car AC system that is slightly low?

Accepted Answer

Add refrigerant as a liquid to the low-side port with the engine running and AC on

Answer

Refrigerant is added as a gas (or low-pressure liquid from an inverted can) to the low-side service port with the engine running and AC on max, never to the high side.

Question 4

What is a common symptom of a failed or slipping AC compressor clutch?

Accepted Answer

AC does not cool at all and compressor pulley spins freely without engaging the hub

Answer

A failed clutch coil or worn friction disc allows the pulley to spin without driving the compressor, so the system produces no pressure differential and no cooling.

Question 5

How does an orifice tube system differ from a TXV system in refrigerant metering?

Accepted Answer

An orifice tube is a fixed restriction; a TXV dynamically modulates flow based on superheat

Answer

The orifice tube is a simple fixed-diameter metering device, while the TXV continuously adjusts refrigerant flow to maintain a set superheat at the evaporator outlet.

Air Conditioning Repair Practice Test

Air Conditioning Repair Practice Test

Air Conditioning Repair Car Air Conditioning Repair 4