2 ton heatpump system at least 11 years old. R22 freon. Replaced open fuse link that allowing electric heat package to turn on to aid heatpump in colder weather. Tested heatpump and checked freon. Was unable to test defrost due to high outdoor temperature. Left quote for new system due to age 9f current system. Electric panel must be upgraded before any installation of new system. Part number SL075B