What is the normal reading for a car air conditioning pressure gauge?
2 Answers
The normal reading for a car air conditioning pressure gauge is 1.3 to 1.7 MPa for the high pressure side and 0.1 to 0.25 MPa for the low pressure side. However, the normal pressure can vary depending on external environmental conditions. The functions of a car air conditioning system are: 1. To achieve cooling effects through the continuous phase change cycle of refrigerant; 2. To remove dust, odors, smoke, and toxic gases from the car's interior air, making it fresher, and to humidify the cabin air. Maintenance methods for car air conditioning include: 1. Avoid setting the temperature too low; 2. Control the direction of air vents; 3. Avoid prolonged use; 4. Occasionally use higher fan speeds; 5. Turn off the air conditioning when driving at low speeds.
As a car mechanic for over a decade, measuring AC pressure is part of our daily routine. Normally, when the compressor is running, the low-pressure gauge typically reads between 1.5 to 2.5 bar (20~35 psi), while the high-pressure gauge is around 15 to 20 bar (200~280 psi). These values aren't fixed—in summer heat, the high pressure might spike to 25 bar, and in winter, the low pressure could drop to 1.0 bar. To measure pressure accurately, keep the engine at 1500 RPM, set the AC to maximum fan speed and coldest setting, and ensure the fan is running properly. If the low pressure is below 1.5 bar, it's likely low on refrigerant; if the high pressure exceeds 25 bar, check if the condenser is clogged with debris. Remember, a large pressure differential may indicate an expansion valve issue, while low pressure on both sides often points to a refrigerant leak.
