I'm curious, and wonder if the old 4 was a flat bed, or sloped, like KA6's and larger. The new KAA-4 appears to have the same flat bed style stoker and feed motor as the KAA-2. http://keystoker.com/new.phphttp://keystoker.com/products.php#cfb
I must wonder if folks there at Keystoker ever look at their website. They list the KAA-2 as having one 3 x 14" grate ?????. Although I've never R&R'd them, it sure appears as though mine has three grates. They list the KAA-4 as having 4, so assuming that it IS a flat bed, perhaps it's stoker is similar to the 2's, but is wider, and actually has 4 grates, vs 3? Otherwise, how can they raise the btu from 76k net to 105k net?
p.s. - while in gripe mode, I'll add that they list hopper capacity as 200# one place, and 240# in another.
Yes, I wanted a 4, but they didn't offer them when I bought.