R-Pro › Field cases › Air conditioning
Capacitor μF Measurement — LCR Meter / Multimeter Capacitance Mode
Likely causes
Discharge residual voltage + select test mode
Check: **Safety**: power OFF + breaker OFF + discharge across terminals with insulated screwdriver (10–15 sec). NEVER measure with power on (shock/equipment damage). **Tool choice**: LCR meter (precision, 1% error) vs multimeter capacitance mode (convenient, 5–10% error). Residential = multimeter sufficient (actual ±6% tolerance). **220V single-phase compressor uses both Start and Run**. Start cap = 35–80 μF / 250V/370V. Run cap = 7.5–50 μF / 370V/440V. Rating printed on nameplate or body.
What to do: **Procedure**: 1) Multimeter to capacitance mode (F or μF). 2) Connect leads to both terminals. 3) Read after display stabilizes. **Pass/fail**: within ±6% of rated = OK. Outside ±6%, ∞, or 0 = bad (replace). **Bulged/leaking/burst** = visual is enough, replace immediately. **Replacement**: match μF, voltage, pinout (higher voltage OK, lower NOT). **Discharge again after measurement** (the multimeter charges it). **Log**: nameplate rating, measured value, replacement date in report.
**Field trick**: multimeter + capacitance mode = used by 90%+ of Korean techs as the common tool. LCR is for R&D/precision. **Residual voltage accidents are common** = always short with insulated screwdriver before work. **R-32 new inverters** = caps degrade less visually/capacitively, but EMI filter caps also exist = inspect those too. **Part prices**: residential start cap KRW 5–30k, run cap KRW 10–50k (Korean market).
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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