Burner starts but flame is unstable and goes out, followed by lockout

Safety: Isolate power and close the gas valve before working on the burner. Wait for the furnace to cool.

• Clean ionisation electrode: Remove and clean the electrode tip with fine abrasive pad to remove oxidation. Ensure the electrode is positioned correctly in the flame envelope as specified by Hoval.
• Check grounding: Verify that the burner plate and control panel earth wires are securely fastened to clean metal surfaces. Tighten loose screws and remove corrosion.
• Inspect burner head: Remove the premix burner head and check for blocked ports or corrosion. Clean with a soft brush and vacuum. Do not use sharp tools that may damage the burner surface.
• Check combustion air path: Ensure the combustion air intake and fan housing are free of dust and debris that could disturb the flame.
• Test operation: Restore gas and power, reset the lockout, and observe the flame through the inspection window. If the flame remains unstable or the fault recurs, a technician must check gas valve settings and the control board.