Checked high and low volt connections at indoor and outdoor Poured 2 gal of water down drain line Checked charge Delta t of 22 79 return 57 supply T stat was set for 72 customers home was 79 all day unit finally turned on shortly before my arrival I found the old t stat had the code for low battery displaying Went ahead and replaced t stat with a t-4 Honeywell the customer was given at the original install left system on in cooling upon departure