What are common faults in oil burner ignition transformers?

Common faults include insulation breakdown, cracked ceramic insulators, moisture ingress, degraded secondary windings, loose electrical connections, and overheating. Symptoms often include weak or intermittent spark, buzzing noise, failure to ignite fuel, or repeated burner lockouts. Because ignition transformers operate at high voltage, degradation can progress rapidly, and replacement is often safer and more reliable than repair once faults are detected.