Unit shuts down during or after harvest; control board beeps four times repeatedly
Safety Warning
This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.
If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.
Possible Causes
How to Fix / Troubleshooting
Safety First: Disconnect power before accessing internal components. Avoid bending refrigerant lines.
- Locate thermistors: On most Hoshizaki models, there is an evaporator thermistor clipped to the evaporator plate and sometimes a discharge line thermistor on the compressor discharge line.
- Inspect mounting: Ensure each thermistor is firmly clipped to clean metal surface. If loose or hanging, reattach with the proper clip or thermal compound as specified by Hoshizaki.
- Check for damage: Look for cracked sensor heads, cut wires, or corroded connectors. Repair or replace damaged wiring.
- Test resistance: With power off, disconnect the thermistor from the board and measure resistance with a multimeter. Compare to Hoshizaki service manual temperature/resistance chart (e.g., around 5–10 kΩ at room temperature depending on model). Replace if readings are far out of spec or open/shorted.
- Reset and monitor: After replacing or reseating thermistors, restore power and reset the unit. Monitor operation through at least one full freeze and harvest cycle.
When to call a technician: If thermistors test good but the 4-beep code persists, the control board’s temperature sensing circuit may be defective or there may be a true high-temperature condition due to sealed system issues.
Repair Difficulty
Required Part
We may earn a commission from links on this page.