For this job I performed an evaluation originally scheduled as a a double ST. I completed all portions of the ST but had to evaluate the bigger unit that serves the upstairs area due to low delta and low refrigerant reading on gages. Leak detector went off several times in the evaporator coil but could not pin point an exact spot. I spoke about options between adding refrigerant but the risk of it exasperating the issue and potentially making the leak worse, replacing the evaporator coil as a repair and adding refrigerant once done but informed homeowner of potential near future failures due to age of the unit and considering it has been running with low refrigerant, or replacing the entire unit due to outdated current refrigerant and age of the unit itself. Home owner requested an email of the repair and refrigerant options and a CA to be scheduled between 10-12 Saturday to give an exact estimate for a whole system replacement. Thank you for choosing comfort experts, have a great day!