The furnace has power but does not respond to the room thermostat; no heating demand is indicated.

Safety: Turn off power before altering control wiring.

• Check thermostat settings: Ensure the room thermostat or programmer is set to 'heat' mode and the temperature is above the current room temperature.
• Override timer: Set the programmer to 'constant' or 'manual on' to rule out timing issues.
• Check batteries: If using a wireless thermostat, replace the batteries and ensure the receiver shows a signal.
• Inspect wiring: A professional can verify that the thermostat wires are correctly connected to the Chaffoteaux control terminals and are not broken.