So I was gonna replace my gas furnace filter today before the cold weather
starts, or at least the cold night weather. But for the life of me I can't
find any information on or about my gas furnace - except for the brand and
the date of installation. Heck, even the filter is one of those freeform
washable filters that doesn't have a cardboard border with the dimensions on
it (basically just a rectangular mat of green fibers that is totally
impregnated with dust and looks about a useful as a third tit). So I took
it out and measured it - it comes out to be 14x27

So I go out looking for a filter for it and no one I know of sells anything
even remotely like that size, 14x30 14x24 14x25 but not 14x27.

So anyway I have a Payne furnace installed in 1983, there is a wiring
diagram on the inside of the filter cover and that give a model number of
397H or 375A but that's it. There's nothing on the outside of the furnace
and nothing that I could see on the inside where the motor and burners sit.

So what's the story, the Payne homepage is about a useful as a 4th tit and I
couldn't pull anything up about a 375 or 397.