I arrived for a possible recall on a system throwing codes. I spoke with the homeowner and found that the system is throwing a code of DF. I explained that the DF means it’s in defrost and the system will take 5-15 minutes to go through its defrost completely. I recommended to let the system finish its defrost cycle completely before turning thee system off. I the system is taking to long in defrost the manufacture specifications state to add all new refrigerant back in from 0 and to change the defrost sensor. I made this known to the homeowner and we decided to see how it runs for now.