R-Pro › Field cases › Air conditioning
AC Completely Inoperative — Power, Breaker, Compressor, PCB Diagnosis
Likely causes
Step 1 — Check power, breaker, outlet (most common cause)
Check: Check whether AC dedicated breaker is tripped at panel. If in trip position (middle), never reset immediately — find trip cause (overload/short/leak) first. Voltage: single-phase 220V ±10%, three-phase 380V ±10%, phase balance within 3%. Outlet/plug = check for discoloration, rust, looseness.
What to do: Simple trip (cause cleared) = OFF→ON reset. Repeated trips = check compressor insulation (megger ≥1 MΩ), wiring shorts, faulty start capacitor. Burnt/melted outlet = replace immediately (fire risk). Low voltage = contact utility/building manager.
Power/breaker = root cause in ~60 of 100 cases. Compressor insulation <1 MΩ on megger = replace compressor (coil short). Never force repeated reset — fire/shock hazard. Inverter PCB = use built-in self-diagnostic codes (separate case).
All 565 cases work offline in R-Pro, with error codes for 62 brands and P-T data for 108 refrigerants.
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