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Manitowoc SM-50 ice machine keeps freezing up
I have a 2-3 year old Manitowoc SM-50 undercounter machine that keeps freezing up. When the ice production begins to dwindle (like every 6 months) I do a thorough cleaning per the manual. This time after doing it, it will drop 2-4 batches of ice, then the entire bottom of the evaporator ices up, creating a 1/2″ to 1″ thick slab of ice under the cubes, locking the cubes in place and not allowing them to drop. I shut the machine down and allowed it to thaw. That evening I inspected it to the best of my abilities, thought everything looked good, then restarted the machine, thinking the big freeze was a fluke. It began to drop ice, but the next morning the bin was once again empty and the bottom or the evaporator was again frozen. I shut it down, let it thaw, and re-cleaned/sanitized the ice pockets on the bottom of the evaporator. Same results… drops a couple batches, then freezes up.
Anyone have a clue as to what’s up? I’m not a professional refrigeration guy, but being in construction my whole life, I usually have a pretty good grasp on DIY maintenance… not this time, though.
Any help would be appreciated.
Matt
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7 Replies
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First clean the machine with Manitowic cleaner. Not a aftermarket one. Then dry the evaporator and inspect it with a light. Look for a haze on the back of the plates and that the cube separators are fully seated to the back plate.
I’m enclosing a tech manual for the machine. But be careful to only use the parts that refer to the SM 50. On Page 145 it a trouble chart. Being as they don’t use a plate probe to trigger harvest, This machine times the cycle with a thermistor. Also harvest is critical to water flow. If pressure is low it will do what your saying. The water fill valve does have a filter.
Also check with a level if the machine is level. Very important with Manitowoc machines for proper harvest.
This is the manual; 80-01111-9_Handbook.book
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Thanks for the manual, and for the added details. I’m not gonna have time to mess with it until this weekend, but I’ll update this thread with my results when I do.
Thanks again, fixbear.
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Fixbear,
Totally cleaned the entire machine again, paying particular attention to the top of the evaporator (which I honestly never even got to on previeous cleanings, not knowing magic was happening above the ice accumulator). Overnight I got 1/4 bin full, but upon inspection, the bottom of the evaporator was completely iced up again.
After I descaled and sanitized this time, the evaporator was still hazy looking, despite all the scrubbing. Could I have screwed it up beyond repair by using non-manitowoc descalers the first tiem I did a thorough cleaning on this thing? Otherwise the unit is leveled perfectly and water pressure is not an issue. If so, that’s a pretty costly rookie mistake.
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With a wooden edges tool, See if it comes off by scaping or not. If it will come off, run a extended clean cycle to remove the calcium. If not, and the evaporator is etched/pitted, you may have to replace the evaporator. And yes, non OEM cleaners will do that. Especially the old contour cube Scotsman’s.
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BTW, Do you have adequate water filtration on this machine? Ice machines and coffee equipment have to have low minerals to survive any length of time.
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I have a fairly clean water source, but no softener. Our water supply is from a pond (very rural area) which goes through a floating filter on the pond, a carbon filter in the house, and another chlorinator before being dispersed to all the water fixtures. Never had any significant issues with calcium buildup in any basins or bowls, and it’s never been a cause to poorly functioning fixtures or equipment
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Four consecutive descaling cycles followed by a sanitizing cycle and I finally have a full bin of ice. I appreciate the insight, Fixbear.
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