Outdoor Water Solutions FCU0039 Freeze Control System Self-regulating unit monitors changes in line pressure and automatically unfreezes any blockage When added to any ows wind-driven aeration system, the freeze control system will keep the line from freezing and allow airflow to continue Hinder ponds from freezing and reduces the need to break ice in winter months. FCU0039 Self-regulating unit monitors changes in line pressure and automatically unfreezes any blockage When added to any ows wind-driven aeration system, the freeze control system will keep the line from freezing and allow airflow to continue Hinder ponds from freezing and reduces the need to break ice in winter months.