WE PURCHASED A HOUSE THAT THE PREVIOUS OWNER DID NOT HAVE THE MANUAL TO THE GAS FIRED WARM AIR FURNACE. I'M A LITTLE CONFUSED ON THE DIRECTION AIR DUE TO THE CONFIGURATION AND NOT HAVING ANY INSTRUCTIONS. AIR FILTERS SPECIFY TO POINT TOWARDS THE BLOWER, BUT THE LARGE DUCT GOES THE OPPOSITE DIRECTION. THE MODEL IS A GE 21LD125B2A. A MANUAL WOULD SOLVE ANY PROBLEMS THAT I MIGHT HAVE IN THE FUTURE AND AT LEAST INSTALL THE AIR FILTER CORRECTLY. I HAVE GONE ONLINE AND READ MANY FORUMS, BUT NONE ADDRESS THIS MODEL AND CONFIGURATION.