R-Pro › Field cases › Air conditioning
AC Weak Cooling — Outdoor Fan Stopped / Slow Speed
Likely causes
Step 1 — Check fan motor, capacitor, blade
Check: Fan stopped = discharge pressure spikes → high-pressure cutout within 5 min. Measure motor winding resistance (single-phase 0.5–5 Ω per manual) — ∞ = open. Run capacitor capacitance (within ±6%). Blade = check for insects/bird nest/bent/cracks. Inverter fan = verify PCB DC signal.
What to do: Power OFF + breaker OFF first. Measure motor winding resistance with multimeter (single-phase 0.5–5 Ω, open = ∞). Run capacitor capacitance (within ±6%). Blade = check insect/bird nest/bend/crack. Inverter fan = measure PCB DC output. Identify faulty part, then proceed to replacement step.
Summer = bird nests common (dark interior). Pre-season inspection mandatory. Bent/cracked blade = crack expands during rotation, risk of housing damage. Replace immediately. Motor open/cap fault = often replaced as a unit (parts hard to separate).
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