Boiler will not fire, control display indicates 'Hard Lockout' and may show an associated fault code, requires manual reset.

Safety first: Turn off power to the boiler and close the gas shutoff valve before removing any covers. If you smell gas, evacuate and contact your gas supplier or fire department.

Step-by-step:

• 1. Note the lockout condition: Many Weil-McLain controls (e.g., Ultra, ECO, GV90+, Evergreen) will show 'Hard Lockout' plus a sub-code. Record this for reference.
• 2. Check gas supply: Verify the manual gas shutoff valve to the boiler is fully open. Confirm other gas appliances in the home operate normally. If not, contact the gas utility.
• 3. Inspect flame signal path: Remove the burner access panel and visually inspect the flame sensor/igniter assembly for cracks, heavy oxidation, or soot. Clean the flame rod with fine emery cloth and wipe with a clean dry cloth.
• 4. Check vent and air intake: For condensing models (Ultra, ECO, Evergreen), inspect PVC vent and intake pipes for blockages (ice, leaves, nests). Clear any obstructions and ensure terminations are not submerged in snow.
• 5. Reset the control: Restore power, then press and hold the reset button on the boiler control or user interface as specified in the manual. Observe the ignition sequence.
• 6. If lockout returns: Do not continue resetting. Persistent hard lockouts indicate a combustion, gas valve, or safety circuit problem that must be diagnosed with a combustion analyzer and manometer.

When to call a professional: If the boiler repeatedly enters hard lockout, or if you suspect gas valve, control board, or combustion issues, contact a qualified Weil-McLain service technician.