Furnace runs but produces no heat; supply air is cold

Safety: Turn off power and gas before internal checks.

• Check thermostat settings: Ensure the thermostat is set to HEAT and the setpoint is above room temperature.
• Verify gas supply: Confirm the manual gas shutoff valve near the IVT furnace is open and other gas appliances work.
• Look for error codes: Check the IVT display for any active fault codes and address them first.
• Reset furnace: Turn off power for 30 seconds, then restore. Some lockouts clear with a power cycle. If the burner still does not light, the gas valve or ignition system may require professional diagnosis.