Be careful!
There really are 2 different series of the 21's. The true Hobart Built units and the Whirlpool influenced units.
The '21' series came out in the early 80's and were the best Dishwashers Hobart designed EVER! They literally have a garbage disposer built into the pump housing. Not some flimsy spring or cutter knife, but a metal drain impeller with a sizing ring set up to break down anything that gets in its way. That impeller then fed the water and debris into the soil collection chamber and filtered that water through the very fine mesh filter you see under the washarm.During the rinse portions, the soil was washed down the drain.
The way to tell the True Hobarts from the WP models is that they all had the heating element in the sump next to the pump and all had the hot air blower/dryer setup under the tank. They also had the heat indicator light on the control panel. These units heated the was water in each cycle to 140 degrees with 1400 watts and then used the 700 watts to keep it hot.
The Whirlpool models were the ones with the exposed heating/drying element above the sump inside the tank and they did not interrupt the timer to heat the water. It was kind of hit or miss if it ever got to 140 since it would not interrupt the timer from advancing.These units also had the plastic blower unit in them and that water element doubles as the dryer element, cycling on and off during the drying phase. You could select no heat dry in either series.
The Superba, Patrician and Monterrey models were the only models with the rapid advance timers on them. The Monterrey was the same as the Superba and was probably a special unit made for specific appliance dealers as my aunt got one and I had to check with Hobart at the time to make sure of what it was since she wanted the top of the line only! And by the time WP got it, the Monterrey was gone.
They are great machines and will wash the pants off anything out there today and do it faster too!
Don't hesitate to take the Imperial..no matter what series you get, it will not disappoint you! Do get yourself a spare washarm support assembly as that was the only weak point in the whole line. The lower white nylon bushing in the support would often come loose and move up and block all the water to the lower arm after a few years, though many originals are still going strong.
Here are some pictures of what the control panel would look like. This is my KDC21D which was an upgraded model with all the features and cycles of the KDI model. This happens to be a 1986 model and was a Whirlpool inspired unit but has worked flawlessly since then!
