Diedrich IR-12 exhaust diameter

[Gila]

It seems like some older model year Diedrich IR-12's required a single 5" or 6" ID exhaust duct, but I just learned that the 2014 IR-12 requires an 8" ID instead. Does anyone know what year Diedrich enlarged the exhaust port on the IR-12 to 8"?

 

[sae]

they increased the BTU/hr rating but I'm not sure if this alone accounts for the need for a larger exhaust

 

[Gila]

Just heard back from their tech support: the 8" exhaust outlet began with model year 2007.