Furnace will not start; no burner ignition, lockout indicated on IVT control display

Safety first: Turn off electrical power to the IVT furnace at the breaker and close the gas shutoff valve before touching any internal components. Allow the unit to cool.

• Check gas supply: Verify the manual gas shutoff valve to the furnace is fully open. If other gas appliances are also not working, contact your gas supplier.
• Inspect ignition electrode: Remove the burner access panel. Locate the ignition electrode on the IVT burner assembly. Check for cracks, heavy carbon buildup, or a broken ceramic insulator. Clean the tip gently with fine emery cloth and ensure the electrode gap and position match the IVT service manual.
• Check flame sensor: On many IVT furnaces the flame sensor is integrated or mounted adjacent to the ignition electrode. Remove the sensor, clean the metal rod with fine steel wool, and reinstall ensuring a solid connection to the control board harness.
• Verify wiring: Inspect the harness from the IVT main control board to the gas valve and ignition module for loose plugs, corrosion, or damaged insulation. Reseat all connectors firmly.
• Reset lockout: Restore power, open the gas valve, and follow the IVT manual to reset the lockout (usually by cycling power or pressing the reset button on the control). Observe ignition. If the code returns, the gas valve coil or ignition module may be defective.

Do not attempt to adjust internal gas valve settings yourself. If ignition still fails, contact a qualified IVT service technician.