Tech performed ESA on 1 system. Tech found no challenges with system operation, tech did find system in level, not allowing water to drain properly out of drain pan, a decent amount of rust has formed and system is only 3 years old. May need to send install team out to adjust system. Check and see if we installed system, no recent installation in previous invoices. Delta T was only 15 degrees, when install team comes out, pressures may need to be checked. System back up and running upon departure.