Status LED on Concord furnace is solid ON with no flashing; furnace may or may not operate.

Note: A steady ON LED on many Concord furnace control boards indicates normal operation or standby, not a fault.

Checks:

• Thermostat settings: Ensure the thermostat is set to HEAT and the setpoint is above room temperature. Replace thermostat batteries if applicable.
• Call for heat at board: Check for 24 VAC between R and W terminals at the furnace control board when there is a call for heat. If no voltage, the issue is upstream (thermostat or wiring).
• Fan-only mode: If the blower is running but there is no heat and the LED is steady, the thermostat fan switch may be set to ON instead of AUTO.

Action: Correct thermostat settings or wiring as needed. No part replacement is required if the furnace operates normally when called.