R-Pro › Field cases › Air conditioning
AC Compressor Overload — Thermal / Current Protection
Likely causes
Identify overload cause (overcharge, low clearance, start cap, compressor itself)
Check: Run current = exceeding 1.2× nameplate RLA = overload. Compressor shell temp >90°C = overheating. Loud start noise/judder = bad start capacitor or single-phase lockup. Internal thermal protector = self-reset in 30 min–2 hr. Repeated trips = winding insulation or mechanical fault.
What to do: Measure run current with clamp meter. >1.2× nameplate RLA = stop and trace cause. Compressor shell >90°C = check ventilation, clearance, overcharge. Single-phase lockup = try replacing start capacitor. Megger insulation <1 MΩ = replace compressor. Never force restart.
Compressor = most expensive part (USD 200–700 residential). Restarting without fixing overload cause = permanent damage. Insulation <1 MΩ = replace compressor. New compressor swap = vacuum + weighed charge + filter-drier mandatory.
All 565 cases work offline in R-Pro, with error codes for 62 brands and P-T data for 108 refrigerants.
Open R-Pro →