Why is air conditioning pressure important?

The air-conditioning system is based on the refrigerant circuit, which undergoes compression and expansion processes followed by heat exchange. The system pressure plays a key role in the proper functioning of these processes. Too high a pressure can lead to overheating of the system, damage to the compressor or condenser. Too low a pressure results in a decrease in cooling capacity and can also cause air or moisture to be drawn into the system, leading to corrosion and other damage.

A/C system pressure depends on the type of refrigerant (R134a or R1234yf), ambient temperature and system load (e.g. fan speed).

Indicative pressure values:

Low pressure (low pressure side – after expansion of the medium):

At an ambient temperature of 20-25°C: 1.5-2.5 bar.

At higher temperature (30-35°C): 2.0-3.0 bar.

High pressure (high pressure side – after refrigerant compression):

At ambient temperature of 20-25°C: 8-12 bar.

At hot weather (30-35°C): 12-17 bar.

It is worth remembering that the above values may vary depending on the vehicle specifications and the type of A/C system.

What do incorrect pressure values mean?

1. Pressure in the high-pressure system too high:

Causes: excess refrigerant in the system, blocked condenser or radiator fan and insufficient heat transfer in the condenser.

Consequences: Overloading of the compressor, risk of damage to system components.

2. Pressure in the high-pressure system too low:

Causes: insufficient refrigerant, leakage in the system and damage to the compressor.

Consequences: Lack of effective cooling.

3. Pressure in low pressure system too high:

Causes: Contaminated evaporator, excess refrigerant, problem with expansion valve.

Consequences: Inefficient cooling, excessive load on the compressor, blockage of lines in the system.

4. Too low pressure in low pressure system:

Causes: refrigerant leakage, malfunction of expansion valve and blockage of lines in the system.

Consequences: Lack of cooling, seizing of the compressor.

Summary

The correct pressure in a car’s air conditioning system is the key to its efficient and trouble-free operation. Both too high and too low pressure can lead to serious technical problems. Therefore, regular inspection, servicing and care of the system’s tightness are essential.