Bosch Combustion Fan or Inducer Noise

Furnace emits a high-pitched whine or loud humming during operation

This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.

If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.

Possible Causes

Worn fan bearings, Debris in fan wheel, Fan wheel rubbing housing, Loose mounting screws

Safety: Switch off power before removing panels.

Visual check: Access the combustion fan on the Bosch unit. Inspect for debris or foreign objects in the wheel and remove them.
Mounting: Tighten all screws securing the fan to the housing and the housing to the chassis.
Wheel clearance: Spin the wheel by hand to ensure it does not rub. If it does, the fan may be bent and require replacement.

Persistent bearing noise indicates the fan assembly should be replaced.

Medium 3/5

Combustion Fan Assembly

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