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Cooler Fan Won’t Start or Runs Slowly: Capacitor or Motor?
Nov
If the cooler pump runs but the fan doesn’t, or the fan is weak, the fault is usually the run capacitor or the fan motor. The capacitor is much cheaper, so it’s worth ruling it out first.
Safety: motors and capacitors are mains-voltage parts, and capacitors can hold a charge after the power is off. Diagnosis and fitting should be done by a licensed electrician or qualified cooler technician.
Symptom guide
| Symptom | Most likely |
|---|---|
| Motor hums but the fan doesn’t turn, and starts if spun by hand | Run capacitor |
| Fan runs slower than normal, or high speed sounds like low speed | Run capacitor (lost capacitance) |
| Motor shaft is stiff or seized when turned by hand (power off) | Motor bearings – replace the motor |
| Burning smell, trips the circuit breaker, or the motor is very hot | Motor windings – replace the motor |
| Loud rumbling or squealing | Motor bearings, or on belt-drive coolers a worn fan belt |
| Fault code on the controller and the fan won’t run (direct-drive models) | Motor, inverter or control box – needs a technician |
Matching a capacitor
Read the label on the old capacitor:
- Capacitance in uF (or mfd): must match, e.g. 25uF.
- Voltage rating: equal or higher, e.g. 450VAC.
- Size and leads: check that it fits the mounting space and suits the connections.
Shop Bonaire motors & capacitors, Brivis motors & capacitors or CoolBreeze motors & capacitors.
Matching a motor
Motors must match the cooler’s wattage, speed type (2-speed, multi-speed or variable-speed), shaft size, mounting and connector. The number on the motor label is often the motor maker’s number, which is different from the cooler manufacturer’s part number. Our product pages list both. See the part number guide.
Breezair Icon models use direct-drive brushless motors with a dedicated inverter drive, not a capacitor. See Breezair motors.
Browse all evaporative cooler motors & capacitors, or send us a photo of your motor label.
This guide is general information only. Always follow your cooler manufacturer’s instructions, and use a licensed electrician for any electrical work.
