Abstract: An improved method of setting a packer in a geothermal well bore under pressure to allow isolation of the wellhead valve including the steps of connecting a lubricator to the wellhead above the valve with the improved packer of the present invention in the lubricator and with a string extending into the lubricator to connect to the packer, running the packer into the well bore below the valve, releasing the packer to allow well pressure to move the packer to set position, disconnecting and recovering the running string, removing the lubricator, repairing or replacing the valve attaching the lubricator, running and connecting the string to the set packer, equalizing pressure across the packer, unsetting the slips and recovering the packer from the well bore.