Boiler will not fire, control display shows “Err 1” and burner never lights

Safety first: Turn off power to the boiler at the service switch and shut off the gas valve before removing any covers. If you ever smell gas, evacuate and call the gas utility or fire department.

• Check gas supply: Verify the manual gas shutoff valve to the boiler is fully open. Confirm other gas appliances in the home work. If not, contact the gas supplier.
• Reset the control: Locate the primary control (Burnham Sage, Beckett, Carlin, or Honeywell). Press and hold the reset button once only to clear lockout. If the boiler lights and runs normally, monitor it. If it trips again, do not keep resetting.
• Inspect flame sensor: Remove the burner access panel. Locate the flame rod/flame sensor. Gently clean the metal rod with fine emery cloth or a Scotch-Brite pad to remove oxidation. Reinstall and ensure the wire connection is tight.
• Check igniter and wiring: Inspect the spark igniter or hot surface igniter for cracks, heavy deposits, or broken ceramic. Check the ignition cable for burns or cuts and ensure it is firmly seated on both the igniter and control.
• Verify burner ground: Ensure the burner chassis has a solid ground connection to the boiler and control. Tighten loose screws and clean corroded connections.
• Restore power and test: Turn power and gas back on, then call for heat at the thermostat. Observe ignition. If there is still no flame and Err 1 returns, the ignition control or gas valve may be defective and a qualified technician should test with a manometer and meter.