Manitowoc Ice SL#2 Error Code
Safety Limit 2 - harvest cycle ran too long (long harvest)
Source: Manitowoc Ice/ud0140a__man-ud-uy-ur-sm.pdf
What does Manitowoc Ice SL#2 mean?
Safety Limit 2 means the harvest time reached 3.5 minutes without the ice slab releasing. On UD/UY/UR machines the board energizes the water pump and extends harvest to seven minutes, then runs water-thaw cycles if the ice damper still will not open and close. After three consecutive seven-minute harvest/thaw cycles the machine stops; the SL#2 light flashes and the Service (wrench) light lights.
Symptoms
- SL#2 light on the control board flashes on and off at one-second intervals.
- Harvest takes much longer than normal and the ice slab is slow to release.
- The ice damper (curtain) does not open and close within the harvest window.
- Machine enters extended harvest and water-thaw cycles before stopping.
- Touch-pad Service (wrench) light is energized.
Common causes
- Ice slab not releasing from the evaporator (poor harvest assist, scaled evaporator).
- Ice damper or water curtain sticking, binding, or its switch/magnet failing to signal open/close.
- Harvest hot-gas valve not opening fully or insufficient harvest heat.
- Water/harvest assist (pump or inlet) not delivering water to free the slab.
- Evaporator scaling or poor heat transfer prolonging release.
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Diagnostic steps
Confirm the safety limit and reset
A flashing SL#2 on the control board indicates long-harvest shutdowns. Reset by pressing the On/Off button and starting a new ice-making cycle, then watch the next harvest.
Watch the ice damper open and close
Observe whether the ice damper opens and closes within the seven-minute harvest cycle. If it sticks or its switch/magnet never signals the position, free or repair the damper assembly.
Verify harvest heat and water assist
Confirm the harvest hot-gas valve opens and the water pump energizes during the extended harvest. Inadequate harvest heat or water keeps the slab bonded to the evaporator.
Inspect the evaporator for scale
Check the evaporator plates for mineral scale that prevents clean release. Descale per the manual if buildup is present, since scaling is a common long-harvest cause.
Run a harvest and time it
Start a cycle and time the harvest. A normal release well under 3.5 minutes confirms the fix; repeated extension into thaw cycles means the harvest fault persists.
When to call a professional
Call a qualified ice-machine technician if SL#2 keeps tripping after you have descaled the evaporator and confirmed the damper moves freely, because diagnosing the harvest hot-gas valve, harvest assist, or control-board harvest logic requires refrigeration gauges and electrical test tools. Three consecutive seven-minute harvest/thaw shutdowns indicate a harvest-system fault that a non-technician should not chase blindly inside a pressurized refrigeration circuit.
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