What Causes Low High Pressure in Car Air Conditioning?

[Billy]

Car air conditioning low high pressure is caused by: 1. System issues: refrigerant leakage, blockage, dirty heat exchangers; 2. Electrical issues: abnormal operation of compressor, solenoid valve, four-way valve, or motor. Under normal air conditioning operation, the low pressure should be around 3bar and high pressure around 15bar. Note this refers to normal operation when the cabin blower is set to the fourth speed, radiator cooling fan runs at high speed, and external condenser has good heat dissipation. The car air conditioning system is designed to cool, heat, ventilate and purify cabin air, providing passengers with a comfortable environment, reducing driver fatigue and improving driving safety.

[DiJesse]

I've encountered the issue of low high pressure in car air conditioning several times, usually due to insufficient refrigerant, meaning there's a refrigerant leak. If there are too many leakage points in the system, the pressure won't rise, and the AC blows hot air, making it feel like the AC isn't on at all. Compressor failure can also cause insufficient high pressure, such as internal wear or a damaged electromagnetic clutch. Or, the AC lines might be blocked, especially if the condenser is too dirty or the expansion valve is stuck. A non-functioning condenser fan can also lead to this, as poor heat dissipation in high-temperature environments exacerbates the issue. I recommend not ignoring these problems—driving in hot weather is unbearable. Get the pressure gauge and safety valve checked at a professional shop as soon as possible. Regular cleaning of the condenser and fan can prevent many issues.

[GabriellaAnn]

As someone who frequently repairs cars, I must say that high pressure and low pressure are often caused by system issues. Refrigerant deficiency is common and requires checking for leaks; compressor failure prevents gas compression; clogged pipelines or filters restrict flow; condenser inefficiency reduces cooling; and expansion valve malfunction affects pressure balance. A pressure test tool can easily identify the issue, with high pressure ideally within the normal range. This problem not only affects cooling but also wastes fuel and increases engine load. Timely maintenance is key, especially checking refrigerant levels and component cleanliness before summer. Otherwise, minor issues can escalate, leading to more expensive and labor-intensive repairs.

[AlyssaMarie]

There are several reasons for low high pressure, mainly due to issues in the refrigeration system. Refrigerant leakage can cause a sudden drop in pressure, compressor wear can lead to poor performance on the high-pressure side, impurities in the pipes or a dirty condenser can cause blockages, expansion valve failure can prevent pressure regulation, or a non-functioning fan can result in poor heat dissipation. This reduces air conditioning efficiency, consumes more fuel, and is not eco-friendly. Keeping the system clean and performing regular maintenance can prevent most failures. Simply put, have a technician check it regularly, and don't wait until it's scorching hot to regret not having cold air.