| AC Not Cooling (Blowing Warm Air) |
Low gas, faulty capacitor, dirty cooling coils, or stuck compressor |
Operating suction pressure, capacitor microfarads, outdoor unit heat release |
Filter wash, capacitor replacement, or leak repair + gas recharge |
| AC Unit Not Starting At All |
Blown fuse, PCB power supply failure, remote sensor fault, or tripped MCB |
Incoming 230V line voltage, PCB transformer, fuse continuity |
PCB repair, wiring repair, or breaker replacement |
| Water Leaking from Indoor Unit |
Choked condensate drain pipe, tilted indoor bracket, or dirty cooling fins |
Drain tray cleanliness, drain hose slope, coil icing levels |
Drain flushing, indoor re-alignment, deep foam cleaning |
| Loud Humming or Rattling Noise |
Worn blower bearings, loose cabinet screws, or outdoor fan blade obstruction |
Motor shaft play, compressor rubber mounting cushions, blower balance |
Blower lubrication/replacement, tightening mounting pads |
| Carrier AC Displaying Error Code |
Sensor open/short circuit, communication error between indoor and outdoor |
Thermistor resistance (kOhm), interconnecting 4-core cable signals |
Replacing room/coil sensor, PCB communication IC repair |
| Frequent Tripping of Electrical MCB |
Compressor winding short, grounded capacitor, or overloaded circuit |
Compressor terminal resistance (C-S-R pins), insulation mega-ohm test |
Capacitor replacement or compressor rewinding/replacement |