Koolaire Ice Machine Water Loss: SL#1 and SL#2 Flashing
Water Loss means the water trough did not fill within 4 minutes of the inlet valve energizing. The machine stops for 30 minutes and tries again. After 100 consecutive failures it locks out, and the SL#1 and SL#2 lights flash together.
High: the machine cannot make ice without water and locks out after repeated failures.
- Code
- Water Loss (SL#1 and SL#2 flashing)
- Maker
- Koolaire
- Equipment
- Ice machines
- Applies to
- Koolaire KT series control board
What does Koolaire Water Loss mean?
Ice is made from a trough of water, so the machine checks that the trough fills. When the inlet valve is energized, the board waits for the water level to be sensed. If the trough has not filled within 4 minutes, the machine stops for 30 minutes and then restarts. This can repeat many times. After 100 consecutive failures, the board locks out and the board shows SL#1 and SL#2 lights flashing at 1-second intervals (Water Loss). The long wait between tries gives a supply problem time to clear, such as a short interruption in the building's water. The manual lists no individual causes in this section. It gives the reset: press the On/Off button and start a new ice making cycle, or switch OFF and then ICE; if it restarts and the condition repeats, call for service. A lockout means the machine tried about two days of waiting.
Affected models and control systems
KT series modular ice machines from Koolaire, the KDT/KYT 0300A, 0400, 0420, 0500, 0700, 1000 and 1700, whatever the cooling type.
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
- SL#1 and SL#2 flashing together
- Trough empty or low
- Machine idle between 30-minute waits
Possible causes
Likely causes — what usually sits behind Water Loss on this control. A technician confirms which one it is before any part is replaced.
- A building water shutoff valve closed or a supply line frozen
- A clogged water filter or inlet screen cutting flow below what the trough needs
- An inlet valve that does not open when energized
- A float or level sensing part stuck so the board never sees the water
Safe checks before calling for service
- Check that the water supply valve to the machine is open.
- Check any external water filter and change it if it is overdue.
- Press On/Off and start a new ice making cycle.
- If the lights flash again, note whether any water enters the trough and call.
How a technician diagnoses Water Loss
- Read the lights and ask when the water was last working.
- Measure incoming water pressure and flow.
- Check the filter and inlet screen.
- Test the inlet valve coil and operation.
- Check the water level sensing circuit before replacing the board.
- Valve and level sensing circuits run on line voltage near water.
- Pressure and flow checks need gauges on the supply line.
- A lockout after 100 failures suggests a firm problem that tests must pin down.
How Water Loss differs from similar codes
Safety Limit 1 and 2 are about freeze and harvest timing; Water Loss shows both lights together and concerns the trough fill.
Technical reference
- Maker documentation
- Koolaire owner support
- Edition
- Part Number 000014142 Rev 04 07/22
- Models / control
- Koolaire KT series control board
- Section
- Section 3 Operation, Safety Limits (p. 27); Section 5 Troubleshooting, Safety Limit Feature (p. 41)
- 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 Koolaire ice machine error codes
Why does it wait 30 minutes?
It gives a short supply problem time to clear before trying again.
What does a lockout mean?
After 100 consecutive failures, the machine stops trying.
Can I reset it?
Press On/Off and start a new ice making cycle.
Need help with Koolaire Water Loss?
A technician confirms the cause on site and gives you the price in writing before any work starts.