What is the CFM of my Heil furnace Model NDGG100DF01
Serial # L874250516

Depends on the speed of the air handler blower. They can be set a number of ways. Typically there are 3 speed settings, marked on the motor. Low, medium and High. You may have a blower with more speeds and thus more CFM. Look at the motor, it will show you what color combinations you can use for the different speeds. You would use a velometer to determine CFM