In an addition in my house before I moved in, a second furnace was installed way up on crawl space. The furnace is a Carrier Weathermaker 9200 and it was installed sideways (really 90 degrees counterclockwise from a normal standing position) just for perspective.
I called up the company that installed it way back when and while they still do exist they no longer travel to my neck of the woods so they can't come out to talk about the installation if their notes were even detailed enough and still kept from the installation.
But I had the instruction manual and so I was able to take off the front cover and then the cover for the area where the filter would normally be (as stated by the instruction manual). Now my other furnace uses disposable filters and I know what they look like. But for this one, I would imagine that they would use a reusable filter. When I open up the compartment, I don't see anything I would call a filter.
It is possible that based upon requirements of the space I suppose that the filter could be relocated to another part, but again looking over the unit, I don't see where that would be. According to the manual page I am posting, it should be #8, and I have a clear picture of that region.
Can you please tell me if you see a filter, and if not, where there might be one for this model?