Burner locks out with indication of flame present at wrong time (flame signal before or after allowed window)

Safety: Disconnect power before working on the burner or wiring.

Steps:

• Check for stray light: Ensure the burner front cover and inspection ports are closed and sealed so no external light reaches the photocell.
• Clean or replace photocell: Remove the Riello photocell and clean the lens. Inspect the body and wiring for damage. Replace if the plastic is cracked or discolored.
• Inspect wiring: Trace the photocell wires back to the control box. Look for pinched, melted, or shorted insulation. Repair or replace damaged wiring.

If false flame is still detected, the control box flame amplifier circuit may be defective and should be replaced.