Furnace attempts to start but locks out with code 1, no flame established

Safety first: Isolate electrical power and shut off the gas supply before opening the combustion chamber. Only qualified personnel should work on gas components.

Basic checks (user/installer level):

• Check gas supply: Ensure the gas cock to the Intergas furnace is open and that other gas appliances in the property work. If there is no gas to any appliance, contact your gas supplier.
• Reset the boiler: Restore power and press the reset button. Observe whether the unit attempts ignition (you may hear clicking) and then goes back to code 1.

Technical checks (qualified technician only):

• Inspect ignition electrode: Remove the burner cover. Check the Intergas ignition electrode for cracks, heavy oxidation, or soot. Clean gently with fine emery cloth and ensure the ceramic is intact.
• Verify electrode gap and position: Adjust to manufacturer specification (typically 3–4 mm gap and correctly positioned in the gas stream).
• Check ignition cable: Inspect the high-voltage lead from the PCB to the electrode for damage or tracking marks. Reseat both ends firmly.
• Measure gas inlet pressure: Using a manometer, confirm correct inlet pressure at the gas valve while the boiler attempts to fire. Adjust or correct supply issues as per Intergas installation manual.
• Check flame detection circuit: If ignition spark is present and gas pressure is correct but flame is not detected, test the flame sensing electrode and associated wiring back to the PCB. Replace the electrode or PCB as required.

Do not repeatedly reset a boiler that fails to ignite; unburned gas can accumulate. If in doubt, stop and call a certified Intergas service technician.