In domeniul instalatiilor, "to dump" se foloseste des si in sensul de "to release", "to transfer quickly"; also colloquial for "to direct"
In concluzie, este vorba despre directionarea aburului, prin intermediul bypass-ului, direct care condensator, fara a fi trecut prin turbina. Este un proces repetitiv, de cele mai multe ori folosit la pornirea turbinei. Aburul va fi recirculat cazan-turbina-condensator-cazan de un numar de ori pana ce ajunge la parametrii necesari trecerii prin turbina.

O explicatie mai amanuntita:
Bypassing the steam around the turbine allows the steam to attain the desired qualities before being routed through the turbine. No steam bypass results in the firing rate of the boiler being reduced, which could lead to tube failures. The bypass system allows the boiler to be fired at full capacity without introducing large thermal gradients in the thick walled components such as the boiler drum and any separators or flash tanks.
In order to protect the reheater tube banks from overheating, the steam is routed around the turbine into the cold reheat piping. This type of arrangement ensures that the boiler can remain in operation during a load rejection, which keeps the safety valves from lifting, and keeps other equipment from tripping allowing immediate reloading of the turbine.