Exhaust steam flows into the top of the exchanger as cool water enters the heat transfer coil from the bottom and flows upward toward the top of the exchanger.

The steam is cooled upon contact with the heat transfer coil containing the cool water and condenses, transferring its latent heat. As a result, the temperature of the water in the coils rises.

The resulting condensate drips down to collect in the base of the exchanger. Once the condensate level rises high enough, it flows over the top of the drain pipe and is discharged.