Scotsman NU100 / NU150 / NU220 / NU300
Undercounter cuber with an ice thickness sensor, magnetic bin-full switch on the ice slide and a condenser temperature sensor.
What it is: Undercounter cube ice machine. R404A undercounter cubers.
Key combo: No service menu. Faults show on the front lights and on the PC board LEDs.
Scotsman NU100 / NU150 / NU220 / NU300 error codes
| Code | Meaning | Likely cause | How to reset |
|---|---|---|---|
| Freezing + R1 lights blinking (SL1 and ZBL1 blinking on the board) | Freeze overtime five times in a row (each freeze over 60 min) | Short of refrigerant, defrost valve fault | Disconnect and repair. The machine harvests by itself after each 60-minute freeze until then. |
| R2 light on (SL1 blinking fast on the board) | Condensing temperature over 70 °C (160 °F) | Blocked condenser, room over 40 °C, fan fault | Once it cools below 70 °C, switch off at the power button, switch back on and wait 3 minutes for the water fill. |
| Bin full red LED on | Ice slide not back in place within 40 s | Bin is full | Clears when ice is removed and the slide resets. |
| Bin full red LED blinking | Bin full cleared within 3 minutes | Normal | Freeze restarts 3 minutes later by itself. |
Normal operating values
| Code | What it does | Range | Default / typical |
|---|---|---|---|
| Freeze cycle length | Normal range | — | 15–40 min |
| High side pressure | During freeze | NU100/220 15–26 bar; NU150/300 15–27 bar | — |
| Suction pressure | Falls during freeze to | all models | 5 → 2 bar (58 → 29 psi) |
| Refrigerant charge (R404A) | Factory charge | NU100/150 320 g; NU220 360 g; NU300 400 g | — |
Notes
- The ice thickness sensor does not work with non-conductive (for example RO) water.
For licensed technicians only. This equipment can involve mains voltage, high-voltage microwave circuits, gas and refrigerant. Isolate power (and gas) before opening panels, follow the manufacturer's manual and your local licensing rules (for example ARC refrigerant handling and electrical or gas licences). Wrong settings can spoil food or damage equipment. Check every value on the unit in front of you before changing it.
Based on: Scotsman NU undercounter ice machine service manual. Always check the manual for your exact model and software version.
ServiceModes is not affiliated with Scotsman or any other manufacturer. Written in our own words from the manufacturer's documentation.