Furnace does not ignite, burner does not light, display shows E01 shortly after a call for heat.

Safety first: Turn off electrical power to the furnace and close the gas shutoff valve before removing covers. Wait for hot surfaces to cool.

Steps to check:

• Verify gas supply: Ensure the external gas cock to the Termet furnace is fully open. If other gas appliances are not working, contact your gas supplier.
• Inspect the ionization electrode: Remove the burner access panel. Locate the ionization/flame electrode near the burner on the Termet combustion chamber. Check for soot, oxidation, or cracks. Clean the electrode with fine emery cloth and wipe with alcohol. Ensure the ceramic insulator is not cracked.
• Check electrode position: The tip of the ionization electrode should be in the flame envelope as specified in the Termet service manual (typically 3–5 mm above the burner surface). Gently adjust if bent.
• Inspect burner: Remove the main burner assembly if accessible. Clean burner ports with a soft brush and compressed air. Do not enlarge the ports.
• Check wiring: Verify the ionization electrode lead is firmly connected to the control board terminal (often marked “ION” or similar on Termet boards). Look for damaged insulation or loose connectors.
• Reset and test: Restore power and gas, then reset the furnace according to the Termet user manual (usually by pressing the reset button or cycling power). Observe ignition. If E01 persists, the gas valve coil or control board may be faulty.

When to call a professional: If you suspect low gas pressure, a defective gas valve, or if you smell gas, stop and contact a licensed gas technician or Termet service center.