Boiler attempts to start, you may hear the fan and clicking, but burner does not light and control shows 'Ignition Failure' or similar message.

Safety first: Shut off power and gas before removing burner or gas valve covers. Do not attempt to adjust gas valve internals.

• 1. Listen and observe: On a call for heat, confirm the inducer or blower starts, then listen for the igniter (clicking for spark or glowing for hot surface). If there is no ignition attempt, suspect the igniter or control.
• 2. Inspect igniter: With power off, remove the Weil-McLain OEM igniter. Look for cracks, white spots, or broken ceramic. For spark igniters, check electrode gap and cleanliness. Replace if damaged.
• 3. Check wiring: Verify the igniter harness is firmly connected to the control board and not pinched or burned.
• 4. Confirm gas supply: Ensure the manual gas shutoff is open. If other gas appliances work but the boiler does not, the boiler gas valve or control may be at fault.
• 5. Reset and test: Restore power and call for heat. If the igniter glows or sparks but there is still no flame, shut down and call a professional—gas valve and combustion adjustments require licensed service.