Atlantic Stuck Fan Operation

Blower runs continuously even when the thermostat is not calling for heat.

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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

Thermostat fan set to ON, Stuck fan relay on Atlantic control board, High limit switch open causing fan-only mode

How to Fix / Troubleshooting

Safety: Turn off power before accessing the control board.

Steps:

  • Check thermostat: Ensure the fan setting is on "AUTO" not "ON".
  • Observe furnace status: If the furnace recently overheated, the blower may run to cool the heat exchanger until the limit switch resets.
  • Inspect control board: If the blower never shuts off, even after cooling, the fan relay on the Atlantic control board may be stuck closed and the board may need replacement.

Note: Continuous blower operation can also be configured intentionally on some models; verify user settings.

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Repair Difficulty

Medium 3/5

Required Part

Main Control Board (PCB)
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