Ice-O-Matic Ice Machine Error 2: Thermistor Failure

What does Ice-O-Matic POWER LED slow flash mean?

The control board uses a sump thermistor to measure sump water temperature during the freeze cycle. The board uses that reading for its anti-slush function, shutting off the water pump at 36 F in the first 3 cycles and at 28 F at any time. If the thermistor fails, the board has no sump temperature to work with and flags the thermistor failure. In this case it shows as a slow flash of the POWER LED, and the manual notes that it appears in the off state only. The manual's code line says only that the thermistor has failed and names no action. It uses the thermistor for the anti-slush function, not to time the freeze or harvest, so the effect on ice production is specific rather than general. Without a proper reading, the pump shutdown that prevents slush cannot be triggered at the right temperature. Because the code line does not say whether the thermistor is open, shorted or only reading incorrectly, a technician has to measure it. Nothing the operator can do at the panel clears it.

Affected models and control systems

This applies to the Ice-O-Matic Elevation Series CIM modular cubers, models CIM0320 through CIM2046, from the Technical Service Manual dated 1/2020. Error 2 is shown by a slow POWER LED flash in the off state only.

Code numbers and their meaning can change between control generations. We match the full model and control before acting on a code.

What you may notice

• The POWER LED flashes slowly while the machine is off
• The machine may make slushy or poorly formed ice
• Ice quality changes without any other warning
• No other lights show a warning

Possible causes

Likely causes — what usually sits behind POWER LED slow flash on this control. A technician confirms which one it is before any part is replaced.

• The sump thermistor lead has been pinched or has failed where it passes into the water
• The thermistor connection at the control board is loose or corroded
• Scale or damage on the sump has affected the thermistor

Safe checks before calling for service

How a technician diagnoses POWER LED slow flash

1. Read the flash pattern and confirm Error 2.
2. Check the thermistor connection at the board and the lead along its run.
3. Measure thermistor resistance and compare it with the chart.
4. Compare the reading with the actual sump temperature.
5. Replace the thermistor if it fails, then confirm the anti-slush shutdown happens at 36 F and 28 F.

How POWER LED slow flash differs from similar codes

Error 2 is the thermistor failure, shown as a slow flash in the off state, while Error 1 is a quick red flash about cycle times.

Technical reference

Maker documentation

Ice-O-Matic owner support

Edition

1/2020

Models / control

Elevation CIM board

Section

Control Board section, Error Codes (p. 27); Troubleshooting note on the High Pressure Cut-out

Checked

October 2026

We use the maker's document to read the code and do not reproduce it. Always confirm the complete model and control before applying these steps.