Hoshizaki KM and KML cubers (beep alarm control board)
Hoshizaki cubers with a control board that counts out faults as beeps, plus green LEDs that step through fill, harvest, freeze and pump-out. The beep count tells you which safety tripped.
What it is: Modular and undercounter cube ice machine. Covers KM-322/522/622MAK, KM-330/530/730MAK, KM-930/1130MAK2, KM-231B/301B, KM-350/420/520/660M (JZ boards) and the KML F and H series.
Key combo: Count the beeps. Reset with the ALARM RESET button on the control board, power on.
Hoshizaki KM and KML cubers (beep alarm control board) error codes
| Beeps | Meaning | Likely cause | How to reset |
|---|---|---|---|
| 1 | High evaporator temperature (above about 127 °F / 53 °C) | Harvest stuck on: hot gas valve or relay stuck, hot water getting in, shorted thermistor | Press ALARM RESET on the control board with power on (careful: live terminals). |
| 2 | Harvest backup timer (harvest over 20 min twice in a row) | Open thermistor, hot gas valve not opening, expansion valve or liquid line valve leaking by, low charge, weak compressor | Press ALARM RESET on the control board with power on (careful: live terminals). |
| 3 | Freeze timer (freeze longer than the timer setting twice in a row) | Float switch stuck up, water valve or hot gas valve leaking by, pump not pumping, expansion valve fault, low charge, weak compressor | Press ALARM RESET on the control board with power on (careful: live terminals). |
| 4 | Bin control shorted (KML with mechanical bin control only) | Wiring between control board and bin control | Repair or replace the harness, then press ALARM RESET. |
| 5 | Bin control open (KML with mechanical bin control only) | Wiring between control board and bin control | Repair or replace the harness, then press ALARM RESET. |
| 6 | Low control voltage (about 92 VAC or less) | Supply or transformer problem | Red POWER LED goes off. Resets by itself once voltage is back in range. |
| 7 | High control voltage (about 147 VAC or more) | Supply problem or wiring fault | Red POWER LED goes off. Resets by itself once voltage is back in range. |
How to enter service / parameter mode
- Check the dip switches are at the factory settings in the manual for your model.
- Move the control switch to ICE. The red POWER LED should come on with a beep.
- Watch the green LEDs step through the 1-minute fill, harvest, freeze and pump-out. Compare the timings with the table in the manual.
Other useful key presses
| Task | How |
|---|---|
| 1-minute fill | Water valve LED only. |
| Harvest | Compressor, hot gas and water valve (or pump for harvest assist). Typical 1 to 20 min. |
| Freeze | Compressor, fans, pump and liquid line valve. Minimum 5 min, up to the freeze timer. |
| Output test (KML) | Switch S3 runs each relay in turn so you can check the board. |
Notes
- Dip switches are factory set per model. Changing them can affect performance and warranty; check the table in your manual before touching them.
- The KM-350 to 660M manual covers two board versions; alarm beeps are the same.
- Freeze-up detection on some MAK boards shows as a blinking POWER LED rather than a beep count.
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: Hoshizaki service manuals: KM-x22 / xx30MAK(2), KM-231B / 301B, KM-350–660M (JZ) and KML F / H series. Always check the manual for your exact model and software version.
ServiceModes is not affiliated with Hoshizaki or any other manufacturer. Written in our own words from the manufacturer's documentation.