When performing an engine pre-heat for refrigerant removal the technician should do what?

When performing an engine pre-heat for refrigerant removal, the technician should ensure that the engine is warmed up to optimal operating temperature to facilitate the proper flow of refrigerant. This involves running the engine for a specified period, typically around 10-15 minutes, while monitoring system pressures. Additionally, they should verify that all safety protocols are followed, including wearing appropriate personal protective equipment and ensuring proper ventilation. Finally, the technician should check for any leaks before proceeding with the refrigerant removal process.