What Causes High Pressure in Car Air Conditioning?
2 Answers
The reason for low suction pressure and high discharge pressure in the air conditioning system is due to poor circulation in the system, clogged dryer filter; kinked connection pipes; throttle valve not fully opened; or four-way valve not properly switched. Below are specific details about car air conditioning pressure: Under normal conditions: When the compressor operates at 1500-2000 rpm, the high pressure should be around 1.5-2.0 MPa, while the low pressure should be around 0.15-0.35 MPa. When ambient temperature around the vehicle is high: The high pressure may reach approximately 2.5-2.8 MPa, but generally should not exceed 3.1 MPa. Otherwise, the pressure protection will be triggered. To ensure safe operation of the air conditioning compressor, most vehicle air conditioning systems are equipped with pressure protection switches. When the system pressure becomes too high or too low, the pressure switch will be triggered and stop the compressor.
Last year, my old car's air conditioning wasn't cooling properly. When I took it in for inspection, they said the high pressure was too high. The mechanic explained that the most common cause is poor heat dissipation, such as when the condenser is completely clogged with willow catkins and dust, or when the cooling fan isn't spinning fast enough, preventing heat from dissipating and causing the pressure to skyrocket. Additionally, overcharging the refrigerant can also cause the pressure to spike, and another possibility is a blockage or air in the air conditioning lines. In my case, the condenser was too dirty, and cleaning it thoroughly fixed the issue. Before long trips in the summer, it's really important to check, especially for older cars which are most prone to this problem. Excessively high pressure can easily damage the compressor, leading to costly repairs that hit the wallet hard.
