What causes normal low pressure but low high pressure in a car's air conditioning system?
2 Answers
Normal low pressure but low high pressure in a car's air conditioning system is caused by a malfunction or damage to the air conditioning compressor. This type of issue usually requires replacing the compressor with a new one. In a vapor-compression refrigeration system, the compressor is one of the main components. The compressor's role in the refrigeration system is to pressurize the gaseous refrigerant and then send it to the condenser for cooling and condensation. The main causes of compressor damage include: 1. Contaminants or particulate matter in the air conditioning system being sucked into the compressor; 2. Excessive refrigerant or lubricating oil in the system, leading to liquid slugging and damage; 3. The compressor operating at excessively high temperatures or for prolonged periods; 4. Insufficient oil in the compressor, causing severe wear; 5. Slippage of the compressor's electromagnetic clutch, resulting in excessive friction and heat; 6. The compressor being underpowered for the system; 7. Manufacturing defects in the compressor.
A few days ago while driving, I noticed the air from the AC wasn't as cool as before. After checking the pressure, I found the high side was low while the low side remained normal. This is likely due to some compressor issues, such as internal wear or leakage, preventing proper refrigerant compression. Another possibility is that the condenser is clogged with dust, causing poor heat dissipation and resulting in insufficient pressure. I recall forgetting to clean the condenser during the last maintenance, which led to reduced AC efficiency. This issue becomes more noticeable in hot weather, as the compressor is under greater stress and more prone to damage. I recommend regular checks of the AC system, especially cleaning the condenser and ensuring the refrigerant level is adequate. If the pressure remains consistently low, it's best to visit a professional repair shop promptly to prevent further damage and ensure driving safety.
