Automatic start-up condensate drain valves

For the most part, it is attempted to design the processes so that no sagging sections or ascending condensate lines will remain in them. In reality, however, it is often impossible, and it is necessary to direct the lines up and down. In the start-up phase, in particular, this may cause malfunctioning situations in the process, such as water hammers, when hot and cold water masses meet each other in the piping.

As an example, a very common situation may occur whereby a steam trap is installed after the steam distribution manifold but the condensate line is ascending. The steam trap will operate flawlessly as long as there is pressure in the system. When the shut-off valve of the steam manifold is closed, the pressure of the manifold also drops, the steam trap stops operating and the rest of the condensate remains in the manifold. In this case, there is a risk that the hot steam and the cold condensate meet each other and cause strong thermal water hammers in the manifold while the manifold is being started up again.

Spring-actuated valve for the discharge of depressurised lines

Exactly for the reduction of such malfunctions GESTRA has developed a self-operated pressure-controlled AK automatic start-up condensate drain valve.

AK can be set for opening, for example, at 1 bar. If the pressure in the piping exceeds the set pressure, AK is closed, but when the pressure drops and the steam trap stops operating, AK opens and discharges the rest of the condensate into the drain. Accordingly, in the start-up state the AK closes automatically after the set pressure has been achieved.

AK start-up condensate drain valves are perfectly suitable as automatic dischargers of the pipelines if there is a risk that the line can freeze in winter when there is no flow in the piping because of the depressurised state.


  • DN 15-25
  • PN 40
  • Laipoin, kiertein
  • C 22.8

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