Manitowoc Ice Machine Error Code E23: T3 Temperature Sensor
E23 means the T3 thermistor, which reads evaporator inlet temperature, is outside its valid range on a Manitowoc Indigo ice machine. Watch whether the slabs form evenly across the plate and make sure the water valve is open. Keep the entry number handy when you call us.
Low: the machine keeps making ice while the sensor is out of range.
- Code
- E23
- Maker
- Manitowoc
- Equipment
- Ice machines
- Applies to
- Indigo series (non-NXT) control board, Event Log (Service menu > Event Log > View ELog)
What does Manitowoc error code E23 mean?
On Manitowoc Indigo ice machines without the NXT display, E23 flags the T3 thermistor, which reads evaporator inlet temperature, as out of range. The control board uses T3 together with T4 to judge refrigerant feed. By comparing inlet and outlet it can tell whether the evaporator is being starved or flooded, which is what E07 and E08 report. If T3 gives a bad reading, those checks become unreliable. Staff may not notice anything at first, then see uneven ice or longer freezes, and the ice may still look fine in the beginning. The display text for the entry is E23. The sensor sits at the evaporator inlet, so the causes are physical: a loose connector, worn wire insulation, a sensor that has lost contact with the inlet line, or a thermistor that is open or shorted. A technician tests the sensor with a meter before touching the refrigeration side.
Affected models and control systems
Manitowoc Indigo series cubers with the non-NXT control board (Service menu > Event Log > View ELog). E23 concerns T3 at the evaporator inlet; T4 at the outlet has its own number, E24.
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
- Ice slabs uneven across the plate
- Longer freeze cycles
- Often nothing at first
- The E23 line in the Event Log
Possible causes
Listed in Manitowoc's documentation
- A loose T3 thermistor connector at the evaporator inlet
- Worn wire insulation near the evaporator inlet sensor
- A T3 sensor that has lost contact with the inlet line
- A shorted or open T3 thermistor
Other likely causes — what usually sits behind error code E23 on this control. A technician confirms which one it is before any part is replaced.
- Frost and moisture around the inlet connection gradually corroding the terminal
- A sensor displaced when the evaporator area was cleaned
- Insulation around the sensor missing, so the reading follows room air
Safe checks before calling for service
- Watch whether ice slabs form evenly across the plate.
- Make sure the water supply valve is open.
- Keep the machine clean and dry around the evaporator.
- Call us with the entry number from the log.
How a technician diagnoses error code E23
- Read the Event Log for E23 and check for E24 or valve entries.
- Inspect the T3 connector, wire and insulation at the evaporator inlet.
- Confirm the sensor is in firm contact and insulated.
- Measure thermistor resistance and compare it with the chart.
- Replace the sensor only after the reading proves it bad.
- The evaporator inlet area is cold and wet, which makes electrical testing risky for non-technicians.
- A bad T3 can hide or fake a starving-valve condition, so the readings must be verified.
- Comparing the resistance to a chart needs a meter and a reference thermometer.
How error code E23 differs from similar codes
E23 is the inlet-side reading, and E24 the outlet-side one; the board compares both to judge refrigerant feed.
Technical reference
- Document
- Indigo Series Technician's Handbook 000014794 5/17, "Event Log" p.87-91
- Maker documentation
- Manitowoc owner support
- Edition
- Part Number 000014794 5/17
- Models / control
- Indigo series (non-NXT) control board, Event Log (Service menu > Event Log > View ELog)
- Section
- Event Log: code list p. 87, Event Log Detail table pp. 88-91 (Service menu > Event Log)
- 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.
Related Manitowoc ice machine error codes
Can I keep running the machine with E23?
Yes, it will usually keep making ice, but the starving and flooding checks are less reliable.
Will E23 clear by itself?
A loose connector may come and go, but a worn wire or failed sensor stays out of range.
Does E23 mean low refrigerant?
No. It reports a bad sensor reading, not a refrigerant problem. A technician checks pressures separately.
Need help with Manitowoc error code E23?
A technician confirms the cause on site and gives you the price in writing before any work starts.