The present disclosure describes a recovery boiler startup burner assembly that can mitigate the harmful effects of smelt fouling, airflow interference, and operator exposure to hot air from the furnace and win box through use of an extractable startup burner and an isolation chamber engaged to a windbox. The present disclosure also describes a method for safely extracting a startup burner from an active recovery boiler as has method for inserting an extractable startup burner into a recovery boiler during operation.