Manitowoc ice machine won’t dump ice Just freezing into thick block

[fixbear]

You haven’t stated whether the machine locks out. If it has, there will be a code and the harvest light will be flashing. turn the machine off, then on and watch the harvest light. It will flash 1 or 2 times and repeat. That tells us where to look. But I’m going to comment on the most often problem without it.

Has the ice thickness probe been disturbed or the wire from it to the control board? That is what tells the machine that it has made ice and 6 minutes later initiate harvest. The machine then does not go back to icemaking till the evaporator cover opens and trips the ice harvest switch. (Magnetic reed switch) So either that sensor is open or dirty (electrically grounding), or the controller has a problem.

Important,; the machine has to be level with a level both front to back and side to side. When cleaning the ice sensor probe, It has to be well rinsed and I like to wipe it down with alcohol after a cleaning. They tend to get a surface film on them that is conductive from the minerals in the water. Or residual acid from cleaning.

You can test the probe three ways. When the machine is running and starts icemaking (freeze cycle) watch the bottom LED (harvest). As it starts making ice it will initially flicker then stay on longer. When the board sees it solid for 6 seconds it determines that the ice is thick enough to start harvest. But it will continue to freeze for 6 more min. The second way is to use a jumper. turn the machine off and connect between the probe and touch the evaporator as you watch the harvest light. This method has the advantage of also testing the evaporator grounding. The third way is to take a ohm meter, open the control box power off, test for continuity between the probe and 1F terminal on the left side of the board just above the Molex plug.