I have a Manitowoc qd0322a ice machine and trying to do anything that everything to figure out what is wrong. I had a technicain come out and he said that I needed a new water pump, so I replaced that.
The ice machine keeps going into harvest mode. If I disconnect the thickness probe then the ice machine makes ice but obviously the cubes freeze over the probe, but at least I know that it can produce ice. When I plug in the thickness probe, the machine just goes into harvest mode.
I have even tried a new thickness probe but thats not it.
The original problem was essentially the same thing. The ice machine would start up but then it just goes into harvest mode. The tech said that the water pump was not going fast enough and not pumping enough water up to the evaporizor in time, so the machine was reaching its 3.5 minute limit.