NME454, 654 & FME504, 804
SERVICE DIAGNOSIS
Symptom | Possible Cause | Probable Correction |
No ice is made, nothing operates | Unit off due to no power | Restore Power |
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| Unit off due to master switch in OFF | Switch master switch to ON. |
| position. |
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| Unit off due to low water level. | Check water supply, filter, strainer, |
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| float valve. Correct water supply. |
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| Unit off due to ice level sensors | Check/clean ice level sensors. |
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| Unit off due to scale on water level | Clean water level sensor. |
| sensor. |
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| Unit off due to high pressure control | Check for water interruption (water |
| open. | cooled) or fan motor failure (air cool). |
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| Auger motor hums but does not turn. | Auger can’t turn. Circuit board has not |
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| yet shut unit down. |
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| Unit is shut down | Circuit board has shut ice machine |
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| down due to high auger motor amp |
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| draw. Check for cause of high amp |
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| draw, including bearings, gearmotor |
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| condition and scale on auger and in |
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| evaporator. |
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| Low pressure control open | Auger not turning due to: motor |
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| failure; auger relay failure on circuit |
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| board; or gears stripped. Check drive |
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| train. |
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| TXV restricted or not metering. Check |
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| bulb temperature. |
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| Lack of refrigerant. Check for leak. |
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| Check for a restricted system |
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| No power to circuit board. | Check harness |
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| Hi or low pressure cut outs open |
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| Circuit Board gear motor relay will not | Check, replace board |
| close |
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| Water level or ice level sensor failed. | Check, replace sensor |
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No ice, auger motor is turning | Compressor contactor coil is open | Check/replace contactor |
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| Compressor will not start | Check start capacitor. |
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| Check start relay |
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| Check compressor windings |
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| Circuit board compressor relay will | Check, replace board |
| not close. |
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Unit makes ice, but very slowly. | High discharge pressure because of a | Clean the air filter and condenser. |
| dirty condenser |
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| Low capacity because the auger and | Clean the water system |
| evaporator are coated with mineral |
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| scale |
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| Low suction pressure due to low | Locate leak. Recover refrigerant, |
| refrigerant charge | repair leak, replace dryer, evacuate |
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| and weigh in the nameplate charge |
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January 2007
Page 22
