Principle
What is the function of an AC?
The function of an AC is to cool and dehumidify the air inside the vehicle.
Name a basic component of AC.
Compressor, condenser, evaporator, or expansion valve.
What is a common AC problem?
A common problem is low refrigerant levels due to leaks.
Why is refrigerant important?
Refrigerant is crucial for absorbing and releasing heat in the AC system.
What is the first step in diagnosing AC issues?
Check the temperature of the air coming from the vents.
What does the compressor do?
The compressor circulates the refrigerant and compresses it to a high-pressure gas.
What does the condenser do?
The condenser cools and condenses the refrigerant from a gas to a liquid.
How often should AC be serviced?
At least once a year or as recommended by the manufacturer.
What is R-134a?
R-134a is a common refrigerant used in automotive air conditioning systems.
How do you check the refrigerant level?
Use a pressure gauge connected to the AC service ports.
Explain the refrigerant cycle.
The refrigerant cycle involves the evaporation of refrigerant in the evaporator, compression in the compressor, condensation in the condenser, and expansion through the expansion valve.
What role does the evaporator play?
The evaporator absorbs heat from the cabin air, cooling the interior.
Describe a refrigerant leak.
A refrigerant leak occurs when the refrigerant escapes from the system, leading to reduced cooling efficiency.
Explain the impact of refrigerants on the environment.
Some refrigerants can deplete the ozone layer or contribute to global warming.
What tools are required for AC repair?
Common tools include manifold gauges, refrigerant recovery machines, and leak detectors.
What is the purpose of the expansion valve?
The expansion valve regulates the flow of refrigerant into the evaporator.
What is a TXV (thermal expansion valve)?
A TXV regulates the amount of refrigerant entering the evaporator based on its temperature and pressure.
How can you tell if the AC is low on refrigerant?
Symptoms include warm air blowing from the vents and frost forming on the evaporator.
What is the purpose of recycling refrigerant?
Recycling refrigerant prevents environmental contamination and conserves resources.
Explain the role of the pressure gauge.
The pressure gauge measures the refrigerant pressure in the system to identify issues.
Describe how heat exchange occurs.
Heat exchange occurs as the refrigerant absorbs heat from the cabin air in the evaporator and releases it outside through the condenser.
Explain the function of the accumulator
The accumulator stores excess refrigerant and helps prevent liquid refrigerant from entering the compressor
What are the signs of a failing compressor?
Signs include unusual noises, lack of cooling, and fluctuating pressure readings.
Describe the difference between R-134a and R-1234yf.
R-134a has a higher global warming potential than R-1234yf, which is more environmentally friendly. R-1234yf is newer.
What should you do if the AC blows warm air?
Check for low refrigerant, inspect for leaks, and ensure the compressor is functioning.