York Insufficient Airflow / Undersized Blower Speed

Furnace runs but house does not reach set temperature; supply air feels weak.

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Safety Warning

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.

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Possible Causes

Dirty filter, Slow or failing blower motor, Incorrect blower speed tap, Blocked return ducts

How to Fix / Troubleshooting

Safety: Turn off power before adjusting blower wiring.

  • Replace filter: Install a new filter of the correct size and MERV rating. Very high MERV filters can restrict airflow on some York furnaces.
  • Check blower wheel: Remove blower assembly and inspect the wheel for dust buildup on the blades. Clean with a brush and vacuum.
  • Blower speed tap: On PSC motor models, verify that the heating speed tap (often labeled HEAT on the board) is not set to the lowest speed. Adjusting speed should be done per York installation instructions or by a technician.
  • Return air: Ensure return grilles are not blocked and that doors are not creating pressure imbalances that starve returns.
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Repair Difficulty

Medium 3/5

Required Part

Blower Motor
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