Troubleshooting
AC Compressor Problems: Warning Signs and Repair Options
12 March 2026 • 7 min read
How to tell whether your compressor is genuinely failing, what tests a technician should run, and when replacement beats repair.
Symptoms that point to the compressor
Not every cooling failure is the compressor, but these signs raise the suspicion.
- Outdoor unit hums but the compressor does not start.
- MCB trips within seconds of the compressor kicking in.
- Loud rattling or metallic grinding from the outdoor unit.
- Compressor body extremely hot and cutting off repeatedly.
Tests before you accept a replacement quote
Insist on three readings: run capacitor value, winding resistance across all three terminals, and insulation resistance to the body. Many compressors declared dead only need a capacitor or overload protector.
Repair or replace the whole AC?
Under 8 years old and otherwise sound: replace the compressor. Over 10 years, with rusted coils and repeated leaks: a new inverter unit usually pays for itself in electricity savings within a few seasons.