Lower sash parts
A contractor from Denver, Colorado says:
March 8, 2016
I am attempting to repair a lower sash on a prism window. If you raise the sash there is nothing that prevents the bottom of the sash from coming out of the tracks and swinging freely. I don't know if it is a side balance or some sort of guide.
Paul from SWISCO responded:
March 9, 2016
Most Prism windows use coil springs for their window balance systems. You might have a broken bottom pivot bar like the 26-336, which would explain why the sash swings out at the bottom. Can you confirm?