andersen operator set

The 39-389 operator has long arms, but you said you needed short arms. Could the 39-390 be better for you?

I know some customers have used these newer style operators to replace their old discontinued Andersen hardware without and problem, but some reported having issues. Specifically, we heard from some customers that the window sash wouldn't close all the way. My thought is that the operator may need to be installed at a certain distance from the window sash. To be honest, I can't be sure as I've never done it myself, but it may be worth keeping in mind. Try it normally first to see if it works fine.