





Fan runs but moves little or no air — failed motor has lost rotor torque and can no longer drive the blower wheel effectively.
Worn or dry bearings cause grinding, rattling, or high-pitched squealing when the fan is switched on or during continuous operation.
Motor receives power and hums but the shaft does not rotate — seized bearings or a shorted winding prevent the rotor from turning.
Exhaust fan is completely dead even though voltage is confirmed at the switch — motor windings are burnt out and require replacement.
Imbalanced or damaged blower wheel causes strong vibration and rattling in the fan housing, often combined with reduced airflow.





💡 Pro Tip: How to Know Your Vent Fan Motor Has Failed
Your part is likely the culprit if you notice any of the following:
⚠️ Fan runs but produces little or no airflow — motor has lost torque
⚠️ Loud grinding, rattling, or squealing noise on startup or during operation
⚠️ Motor hums but blower wheel does not spin — bearings seized
⚠️ Fan completely dead with power confirmed at the switch — motor burnt out
🔍 Technician Tip: Before ordering, visually inspect the motor for rust staining, burnt smell, or shaft wobble. Verify your existing unit's CFM rating (50 CFM) and confirm mounting stud spacing (1-7/8" on center) matches. The SM550 fits the vast majority of older NuTone/Broan 50 CFM C-frame housings — but always cross-check your original part number against the replaces list above.
📦 What's in the Box
✅ 1× SM550 Vent Fan Motor (120V / 50 CFM / 3000 RPM, C-frame, with 2-prong plug)
✅ 1× FB460 Blower Wheel / Fan Blade (4.5" flat/paddle style)
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Disclaimer: Compatibility information, part numbers, and model fitment data on this page are sourced from manufacturer databases and third-party references. While we strive for accuracy, please verify your appliance model number before ordering. Heima is not responsible for errors or omissions in compatibility listings.
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