Heat and no heat!
No Kitchenaid ever heated its water until the advent of the 15 series and that was only in the Superba models. We are talking standard undercounter units and not the portables which were unique to themselves and had features that would not always be the same as the regular undercounter machines. The later series of 16 and 17 machines were nearly the same with the heating feature only on the Superbas but I do remember a KDI-16 that did have a sump heater but only 700 watts which I converted back to a KDS15 for my Aunt because the 15 tank had a minor leak in the sump. It worked just as well as the 15 with the added feature of a constant rinse but sure took a long time to heat up the final sani rinse to 180 as compared to the standard heater at 1400 watts. Members like Combo52 and others who serviced the domestic lines could vouch for all the stranger combinations that KA produced over the years. And as John often points out, Hobart was probably the last to join the bandwagon when it came to heating the circulating water to a specific set point. Something now needed with the inferior detergents available now.
The 18's continued the heat only in the Superbas as well but once the 19 and higher series came out which preheated the water, all models had some sort of heat source in the sump including all the earlier models of the 21 series. The later 21 units had the sump heater for the Superbas and the Imperial and Custom models had the raised element over the bottom of the tub which also acted as the heat source for the drying portion of the cycles.This carried over into the 22 and 23 series as well, with the 23 series finally having the wash temp delay which insured that you had at least 140 degree water circulating before the timer would advance.
Drying has always been achieved by means of a fan forced heating system with an externally mounted heating element and in later years, on lower level models, a fan forced system that had the water heating element as the heat source which would turn on and off at intervals during the drying sequence.
Energy saving drying was first introduced in the all of the 17A models and continued on the 18, 20 and all later models. Only the 19 series lacked the optional button to turn off the heated dry because there was NO heated dry on it at all. It used the residual heat of the dishes and tank to dry the dishes. As many members always point out, drying results could be enhanced with the use of a drying agent and even still it could be lackluster at best.
So long answer short, no tank heat on the 10's, 11's or 12's but they always had heated dry!
