Do you charge 410A freon as a vapor or liquid?

When charging 410A refrigerant, it is typically added as a liquid to the low side of the system. This approach helps ensure efficient charging and minimizes the risk of damaging the compressor. However, during the charging process, especially when the system is low on charge, it may be necessary to add it as a vapor to avoid flooding the compressor. Always follow manufacturer guidelines for the specific system in use.