What Causes Excessive High Pressure in Car Air Conditioning?
2 Answers
The reason for low pressure and high pressure in the air conditioning system is poor circulation, blockage in the dryer filter; kinked connecting pipes; throttle valve not fully opened; or four-way valve not properly aligned. Below are specific details about car air conditioning pressure: 1. Under normal conditions: When the compressor operates at 1500-2000rpm, the high pressure should be around 1.5-2.0mpa, while the low pressure should be around 0.15-0.35mpa. 2. High ambient temperature around the vehicle: The high pressure may reach around 2.5-2.8mpa, but generally should not exceed 3.1mpa, otherwise pressure protection will be triggered. To ensure safe operation of the air conditioning compressor, most vehicle air conditioning systems are equipped with a pressure protection switch. When the system pressure is too high or too low, the switch will be triggered and stop the compressor.
A couple of days ago, I helped my friend check his car's air conditioning and found the high pressure was way too high. The main issue was the condenser being extremely dirty, completely covered with leaves and insect remains on the outside, making heat dissipation impossible. Additionally, the cooling fan was broken and couldn't keep up at high speeds, causing the whole system to struggle. Overcharging the refrigerant is also a big problem, causing the pressure to spike directly. The most troublesome case I've encountered was a stuck expansion valve, where the refrigerant blocked in the pipes created a pressure cooker effect. Such issues need immediate attention; otherwise, the compressor could be completely ruined, and the repair costs could amount to half the car's value.
