Balance knife shoe issue.

Question

I installed the 15-014 lock show and installed my window as well. However, when I pull the window down, the knife shoe stays at the bottom of the track and doesn't come up with the window. It stays jammed at the bottom of the track. What makes the knife withdrawal and rise up with the window? The knife is engaged into the channel and stays locked in place.

Tom · Accepted Answer

What might be happening is that the shoe is stuck in the locked position, meaning the knife itself is bracing it against the window track. It needs to be depressed so that it stays unlocked while the window is in operation. Usually the weight of the sash does this automatically, though. I would check to make sure that the sash is seated properly.