What rpm when adding refrigerant?

When adding refrigerant to a system, it's generally recommended to do so while the compressor is running at its normal operating RPM. This ensures proper mixing and absorption of the refrigerant into the system. Typically, the RPM will depend on the specific compressor design, but maintaining the manufacturer's specified RPM range is crucial for optimal performance and efficiency. Always refer to the equipment's service manual for the best practices specific to the system in use.