Boiler will not fire, display shows E01 lockout

Safety first: Turn off power to the boiler at the service switch and close the gas shutoff valve before removing any covers. If you ever smell gas, evacuate and contact your gas supplier or a licensed technician immediately.

• Step 1 – Reset and observe: Restore power, open the gas valve, and attempt a reset from the boiler control panel. Watch through the sight glass: you should see sparking and then flame. If E01 returns immediately, continue below.
• Step 2 – Verify gas supply: Confirm the manual gas shutoff valve to the Triangle Tube boiler is fully open. Check that other gas appliances in the home operate normally. If no gas to any appliance, contact the gas utility.
• Step 3 – Inspect ignition electrode and flame rod: With power and gas OFF, remove the burner access cover. Locate the ignition electrode/flame sensor assembly on the burner. Check for cracked porcelain, heavy soot, or corrosion. Clean the metal rod gently with fine emery cloth and wipe with a clean dry cloth. Reinstall, ensuring the gap and position match the manufacturer’s spec (do not bend excessively).
• Step 4 – Check wiring: Inspect the ignition cable from the control board to the electrode for burns, cuts, or loose connections. Reseat connectors firmly on the boiler control board and at the electrode.
• Step 5 – Gas valve check (visual only): Confirm the gas valve on the boiler is not physically damaged and that its electrical connector is fully seated. Do not attempt to adjust gas valve settings yourself.
• When to call a technician: If the boiler still shows E01 after cleaning the electrode and confirming gas supply, a licensed technician should test gas pressure, ignition voltage, and replace the gas valve, ignition electrode, or control board as needed.