Q: What does “back check” mean on heavy duty door closers?

A: “Back Check” stops the door slamming open; two examples:- on an external door in a windy location back check prevents the wind from “picking up” and opening the door (which might damage the frame at the hinges); or when there is a wall at 90° from the door back check stops damage to the wall & door handles by  preventing slamming open.  It’s a standard feature on both the Geze TS4000 door closer and the Geze TS2000NVBC, it’s an optional extra with the Geze TS2000 .