Arrived on site. Found faulty thermostat shutting down the unit. Bypassed the stat and the unit ran without shutting down. Customer had an old thermostat in cabinet. Quoted to install old stat or install new nest. Talked about service agreement to maintain equipment. Also found condensate line without a vent, and the condensate pump was not wired up properly. Customer declined all recommend repairs and just wanted the diagnostic. Reinstalled old nest and collected the diagnostic fee.