Armstrong Air Blower Control or Limit Cycling Without Heat

Furnace blower starts and stops repeatedly without burner ignition; cool air may blow briefly.

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

Stuck fan relay on control board, Faulty fan timer, High limit opening and closing rapidly, Miswired G circuit

Steps to check:

Observe LED codes: Look for any limit or fault codes on the Armstrong Air control board.
Thermostat fan mode: Ensure the thermostat fan is set to AUTO.
Inspect G wiring: Disconnect the G wire at the furnace. If the blower cycling stops, the thermostat or wiring is causing intermittent fan calls.
Replace control board: If the blower relay is chattering or the fan timer is erratic, the integrated control board may need replacement.

Hard 4/5

Integrated Furnace Control Board

Check Price on Amazon

We may earn a commission from links on this page.