It looks like the sill if the window needs to be shimmed up In the middle.

Thanks for the response. Any shimming would raise the sill and the rail the window rolls on because they are one piece. This gap can be filled with the piece in photo 2 and in photo 3 you can see how the window on the rail could slide across this piece and therefore seal it to prevent air loss or insects entering. The problem is that this piece is too big for some of the windows so im trying to find it in different sizes but with no luck.

https://blainewindow.com/

The part when used in a marine environment might be called a “window channel sweeper”. Used on my old boat’s sliding side windows, the sweeper pushed the water out of the track when opening the window.

Thanks again for you response toddinmnand sorry if my response or my understanding was not clear. The house is brick and concrete. The windows are pvc with each window having a fixed sash and a rolling sash that sit inside a pvc channel (Sills?) that forms the window frame. The sashes sit on rails about 1 inch off the bottom of the pvc channel on the bottom and about 1/2 inch between the top sash and the top pvc channel. The pvc channels are level and both ends and the center have the same 1 inch gap. Im sure Kommerling knows exactly whats needed but unfortunately they dont respond to my request for help so i was hoping that someone here could give good avise.

Thanks Jim Mat. When I search this in google I dont see anything simular however since we live in south florida Im going to go to the marine shops and see what they have.

Why don't you just call the manufacturer and ask them to drop a few of the weatherstripping interlocks in you to the mail? I would guess they have a bucket of those on the fabrication line as they are designed to work with their extrusions.

Tried that but the manufacturer does not respond to our emails or calls. This is why im asking you guys for help. I have actually tried that with Kommerling Mexico , USA and Germany with no success. Believe me Im only here as a last resort.

I searched and came up with nothing. Might have to make your own parts.

Thanks for checking.

Call these guys too. They probably have something that is readily adaptable that can just be cut down with a multi-tool to fit your space constraints.

https://blainewindow.com/

This is an ancient post but theyre called window dust pads. If you search for "sliding window dust pads" youll find them!