WM 1-D hi temp!
If you look closely at the picture of the fill solenoid, you will see another valve next to the one in the picture. This makes it a Dual fill machine where incoming water of 140-160 degrees was required for the wash and the second valve was to be supplied with min. 180 degree water for the rinse. These were actually based on the 16/17 machines and originally came with the same sani-guard filters as the 16 and 17 machines.
The wash arm support was later modified from the original style which actually cut down the water pressure out of the Hydro-Sweep arm by removing the brass sealing ring/bearing and let a decent amount of water to leak by and back down into the wash impeller. The plastic filters were replaced by a stainless steel filter. But still, the water hit the top of the tank like someone was inside playing the drums.
The drain was pump assisted in that it flowed into the overflow tee below the machine and was really a gravity drain as well.If it had to pump up to a wall drain, it ran the risk of simply pumping the water back into the tank and then the machine would overflow because there was no float to stop the flow. Overflow was handled by the drain as seen in the above photos.
They were good,hard working and good cleaning machines. The really early ones had an inner door like the 15's but then the later ones came with a door like the 16/17's. Pump motors were the same as the 15-17 designs. Original machines even had a single push button on the right side but that was very quickly eliminated and replaced by a simplified design which was actuated by the door latch.
They would still make a good home machine and being a stainless tank, would last forever. And it was not until the WM5 series that there were models that retained the rinse water for the following wash. They did also produce a WMES-3 which had multiple cycles and may have saved the rinse water but it did not have an element in it either. Short lived machine and problematic.
