Furnace attempts to start but shuts down with E02, fan may run briefly, no stable flame.

Safety: Disconnect power and close the gas valve before opening the furnace.

• Check combustion air and flue: Ensure the air intake and flue terminal are not blocked by debris, snow, or nests. Termet sealed-combustion furnaces are sensitive to flue restrictions.
• Inspect burner and heat exchanger area: Remove the burner cover and visually inspect for rust flakes or debris falling onto the burner. Clean with a soft brush and vacuum.
• Check ionization electrode cable: Follow the cable from the electrode to the Termet control board. Ensure it is not damaged, wet, or loose. Reseat the connector.
• Observe flame (if inspection window is provided): After reassembly, restore power and gas. Watch the flame through the inspection glass. If the flame is lifting off the burner or pulsing before E02 appears, gas pressure or valve modulation may be incorrect.

Professional service recommended: Flame instability due to gas pressure or a defective gas valve requires a qualified Termet technician with a manometer and combustion analyzer.