That is the first KA home model, the KD10. You can tell them by the lack of an escutcheon around the door handle. It has no warm up purge (that came on the 12s)so the hot water for the wash fill is cooled off by the cast iron pump and wash arm as well as the tank and the dishes. KA recommended hot water at 160F and even that gave washes at about 105-110F. If you are going to put really dirty dishes in this machine, let it go through the 5 minute wash and after the drain, restart it with fresh detergent after again running the hotest water to the tap near it. It's not that the water power in this machine is not great, it's mainly that it does not wash at high enough temperatures to give great results on all but the softest soils and the 5 minute wash cycle is too short to have much chance to do a lot with tougher soils. Two 5 minute washes should give better performance, sort of like with the higher rated Hotpoint of the same period.
In their early years, Hobart touted their experience making institutional machines as qualifications for making home dishwashers. The trouble was that their institutional machines were pretty much kept in continuous operation which kept the small undercounter machine hot. The other machines had gas, steam or electric hot water boosters to keep the wash solution hot and health codes mandating 180F final rinse water. Also, restaurants practically wash the dishes before they are put in the DW to save on detergent and the dishes were freshly soiled so any food left on the dishware was easily washed away. A home machine is used at most once after each meal and then cools off so you don't have the benefit of successive loads using the heat built up in earlier loads. Even though the 15 series machines did not use supplemental heat for the wash, the two preceding fills warmed up the machine so well that it was among the best performing machines when tested by CU.