A heat exchanger is primarily used for cooling the hydraulic fluid of the intensifier pump. Typically the hydraulic oil temperature must be kept below 120° F (49° C). The heat exchanger will require a consistent water flow of 0 to 8 gpm (0 to 30 liters per minute) at an inlet temperature not exceeding 70° F in order to keep the hydraulic fluid at the proper temperature. Actual volume of water will depend on the pump selected. As many pumps are thermostatically controlled, when the pump is cool, it may be that no water is required.

This cooling water must go to drain. The cost of this water must be balanced against the costs of the other two cooling options (air-over-oil and chiller), which would not have any water going down the drain.

Public utility water is usually acceptable for cooling purposes. In situations where the water contains heavy mineral deposits, the exchanger tubes may eventually become restricted by particle buildup. If this is a chronic problem, pre-filtration and/or water softening may be necessary.

Depending upon plant setup, ambient temperature can also be a factor in cooling the hydraulic fluid. Additional cooling may be required if the intensifier and/or heat exchanger is confined to a small, high-temperature space.