The hood and duct are separate systems
A blower can run while airflow remains weak because of loaded filters, a damaged wheel, a control problem, a closed damper or resistance in the household duct.
Appliance service can identify faults inside the hood, while building duct conditions may require a separate ventilation provider.
Speed and noise provide clues
Note whether every fan speed works, whether the motor sound changes and whether vibration or scraping is present. These observations help separate control problems from mechanical ones.
Stop using the hood if there is smoke, sparking, loose wiring or a burning odor.
What to send before service
Provide the brand and model, hood style, mounting height and whether safe access requires a ladder. A photograph of the installation can help the office confirm coverage.
This information is general and is not a substitute for model-specific instructions or professional diagnosis. Stop using an appliance if there is a risk of fire, electrical shock, gas, flooding or injury.