Oil cooling systems (OL and OW Series) are designed to circulate transformer oil and are used in applications where the temperature at the heat source exceeds the operational temperature limit of water-based coolants, or when special insulating properties are required within the coolant loop. The OL Series is a recirculating liquid to air heat exchanger that offers dependable, compact performance by removing large amounts of heat from a liquid circuit. The coolant is recirculated using a high-pressure pump to assure maximum flow rate. Heat from coolant is absorbed by a heat exchanger and dissipated into the ambient environment using brand name fan.

The OW Series uses facility water as a hot side heat dissipation mechanism, which increases the cooling capacity while maintaining form factor. The OW Series system is designed to operate using oil as coolant.