Why charge the ac unit on the low side?

Charging the AC unit on the low side is important because it allows for a more accurate measurement of the refrigerant levels and system pressure. The low side is where the refrigerant is in a vapor state, making it easier to assess the system's performance and avoid overcharging. Additionally, charging on the low side helps to prevent potential damage to the compressor, which can occur if the refrigerant is added on the high side. This method ensures a safer and more efficient charging process.