Manitowoc Ice Machine Error Code E20: Water System
E20 means the control board of a Manitowoc Indigo ice machine saw a water-side pattern that does not make sense, such as the high water probe wet while the low probe is dry. Check that the water valve is open and any filter is not clogged, and look for overflow or a low reservoir. Then call us with what you saw.
Medium: overflow or water starvation can stop the machine, though it is often recoverable.
- Code
- E20
- 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 E20 mean?
E20 appears on Manitowoc Indigo ice machines without the NXT display when the board sees a water-side pattern that does not add up. The board watches water level probes, the inlet and dump valves and the evaporator outlet temperature, and it knows what each should be at each stage. It logs E20 when the picture contradicts itself. Examples from the manual include the high water probe sensing water while the low probe does not, an evaporator outlet below -10 F at about seven minutes into freeze, or the low probe being satisfied at the end of harvest. In practice the machine may overflow, starve for water or stop. Staff may see water running into the drain too long or a reservoir that never fills. The display text is E20. Because the pattern can come from scaled probes, a sticking valve, poor supply pressure or a sensor, a technician checks each part of the water path.
Affected models and control systems
Manitowoc Indigo series cubers with the non-NXT control board (Service menu > Event Log > View ELog). E20 is a water-system entry on the non-NXT board; other controllers use different numbers.
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
- Water overflowing or running too long
- Reservoir running low
- Ice production slow or stopped
- Slabs forming thin or unevenly
Possible causes
Listed in Manitowoc's documentation
- Water level probes for scale or wiring
- Inlet water valve and dump valve
- Water supply pressure and filter
- Evaporator outlet temperature sensor
- Reservoir and float area
Other likely causes — what usually sits behind error code E20 on this control. A technician confirms which one it is before any part is replaced.
- Mineral scale coating the probes so the board reads water that is not there
- An inlet valve that dribbles when closed and keeps the reservoir topped up
- A water filter cartridge that is overdue and limits flow
Safe checks before calling for service
- Check that the water supply valve is open and any filter is not clogged.
- Look for water overflowing or the reservoir running low.
- Follow the cleaning and descaling schedule from the owner's manual.
- Call us with what you saw.
How a technician diagnoses error code E20
- Read the Event Log for E20 and note which water pattern was recorded.
- Check supply pressure at the machine and the filter condition.
- Test the inlet and dump valves for sticking or leaking.
- Clean the water level probes and check their wiring.
- Verify the evaporator outlet sensor before replacing any part.
- Inlet and dump valves are energized at line voltage and sit near water.
- The entry can come from several different patterns, so reading the probe states needs the board's own data.
- Descaling requires cleaner, the right procedure and a rinse to protect the food zone.
How error code E20 differs from similar codes
E20 groups several water-side contradictions, whereas E19 refers only to the ice thickness probe.
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 E20?
Watch it. If water overflows or the reservoir runs dry, turn it off and call us.
Will E20 clear by itself?
A clean cycle may let it pass, but scale or a sticking valve brings it back.
Does E20 mean a leak?
Not necessarily. It means the water readings did not agree, and a technician finds out why.
Need help with Manitowoc error code E20?
A technician confirms the cause on site and gives you the price in writing before any work starts.