Performed ac diagnostic grass valley. 20 yr Heat pump split roof and attic. 230. Ac on and operational on arrival. Maintenance said reset breakers and system turned on. Turned down system a few degrees to test system 77 to 75, went into attic for roof access and system running. Left got my tools and back at the air handler opened up system. Tested blower capacitor 5@4.8 ok, no wiring looks to be burnt. Then shut the system off and re cycled system. System working correctly at this time. Dual capacitor ok 25-5. Contactor pitted and starting to burn but, working just fine. Refrigerant pressures ok. Not sure what kept it from working. Performed ac diagnostic on heat pump.