R-Pro › Field cases › Air conditioning
Outdoor Fan Motor Bearing Replacement — Grinding Sound / Rotational Friction
Likely causes
Diagnose bearing wear (friction, noise, heat)
Check: **Field diagnosis**: 1) System OFF + breaker OFF. 2) Spin fan blade by hand → smooth = OK / stiff/catching/grinding = bearing wear. 3) Feel vibration/noise during rotation. 4) Touch motor shell for heat (slight warmth OK in normal operation; >50°C = bearing friction overheat). 5) User reports: 'grinding'/'squeaky'/'metallic' = classic bearing wear. **Progression**: friction → reduced rotation → low airflow → condensing pressure spikes → high-pressure cutout.
What to do: **Bearing replacement procedure**: 1) System OFF + breaker OFF + LOTO. 2) Remove fan guard/blade (mark blade orientation). 3) Detach motor assembly. 4) Remove both bearings together (uneven wear common). 5) **Check bearing part number** (OD × ID × thickness, e.g., 6202ZZ = 35×15×11 mm). 6) Same-number new bearing + correct grease (lithium grease, per motor spec). 7) Press-fit (bearing press or washer). 8) Reassemble motor → confirm smooth manual spin. **Quick lube** (emergency) = inject correct grease, but effect <2 weeks if wear is advanced.
**Field trick**: bearing wear typically discovered after 1+ year of progression (users don't notice). Spot-check by manual spin at season start = 1-minute diagnosis. **Number interchange**: 6202/6203/6205 etc. standard, available at Korean parts shops (KRW 5–30k each residential). **Replace both sides** mandatory; one-side only = imbalance. Whole motor assembly (KRW 150–300k) vs bearing swap (KRW 50–100k) = 5× savings. **Grease type matters** = follow motor spec (wrong grease = bearing damage).
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