A liquid receiver service valve is in which position to finish charging with the compressor on?

The liquid receiver service valve must be in the back seated position to finish charging with the compressor running. When the valve is back seated, it allows the flow of liquid refrigerant into the system while keeping the compressor operational. This position helps to ensure that the receiver is filled appropriately without affecting the pressure in the compressor or causing backflow that could lead to damage or inefficiencies in the system.

Using the back seated position allows for safe and effective charging, as it helps maintain pressure and avoids sending vapor back into the compressor, which can occur if the valve is not properly seated. This is particularly important in systems where precise refrigerant levels are critical for proper operation. The compressor can continue to run without risking the introduction of unwanted vapor phases that might impair its functionality. Thus, the back seated position is essential for successfully completing the charging process while the compressor is on.