Ecobee Continuous Fan Operation

Thermostat shows 'Fan running' even when there is no active heating or cooling call

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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

Fan set to On instead of Auto, Fan minimum runtime configured, Stuck G relay on furnace control board, Miswired G terminal

How to Fix / Troubleshooting

Safety: Turn off power to the furnace/air handler before opening panels if hardware issues are suspected.

  • Step 1 – Check fan mode: On ecobee, ensure the fan is set to Auto, not On.
  • Step 2 – Review fan minimum runtime: In Comfort Settings, reduce or disable minimum fan runtime per hour.
  • Step 3 – Observe furnace board: If the fan runs even with G not energized, the blower relay on the control board may be stuck closed and the board may need replacement.
  • Step 4 – Verify G wiring: Ensure no unintended jumpers are present between G and other terminals at the furnace board.
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Repair Difficulty

Medium 3/5

Required Part

Furnace Control Board
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