How do I read Ice-O-Matic LED indicator light codes?

Ice-O-Matic ICE-series cubers (CIM, ICE0250–ICE2100) and GEM Pearl Ice flakers diagnose faults through front-panel LED indicator lights rather than a numeric display: a Power LED, a Clean LED, a Water LED, and a Bin LED. Each LED has a normal state (solid blue) and a fault state (solid red, slow yellow flash, or fast simultaneous flash) that maps to a specific F/E/HI/LO condition family. The LED pattern plus the on-board service-mode codes printed in the service manual identify the fault — there is no scrolling alphanumeric display on most Ice-O-Matic ice machines.

What does Ice-O-Matic F5 mean?

F5 on Ice-O-Matic CIM-series ice machines is the cleaning-required service code: the Power LED is solid red and the Clean LED slow-flashes yellow (about once every six seconds), and the unit halts ice production. The control board has tracked accumulated run hours since the last cleaning cycle and locked the machine off until a full descale is performed. Recovery: mix Ice-O-Matic-approved cleaner to spec, hold the Clean button to enter the cleaning cycle, drain and sanitiser-rinse, then press and hold Power + Clean for three seconds to reset the controller. Replace the inlet water filter at the same interval to avoid recurrence.

What does HI mean on an Ice-O-Matic ice machine?

HI on an Ice-O-Matic high-pressure / high-temperature indicator means the system has tripped the high-pressure cut-out or the high-discharge-temperature switch — most commonly a dirty air-cooled condenser, a failed condenser fan motor, blocked airflow into the rear cabinet, or, on water-cooled units, a starved condenser water supply. Some larger ICE remote-condenser models also use HI to flag the remote condenser fan or pressure-switch circuit. Recovery: clean the condenser fins, verify fan-motor rotation, confirm at least 6 inches of clearance behind the unit, and on water-cooled units check the inlet supply pressure and the water-regulating valve before resetting power.

What does LO mean on an Ice-O-Matic ice machine?

LO on Ice-O-Matic ice machines flags a low-pressure / low-water condition: either the low-pressure refrigerant cut-out has opened (loss of refrigerant charge, frosted-up TXV, or extended low-ambient operation) or the inlet water supply has fallen below the minimum required for the freeze cycle. On the ICEU undercounter and large-cuber series, LO is wired in series with HI on the safety-control circuit, so the same indicator latches both pressure faults until reset. Diagnostic order: confirm water-supply pressure at the inlet hose first (the cheapest fix), then attach gauges to the low-pressure port to confirm a refrigerant-side problem before calling for an EPA-Section-608 sealed-system repair.

What does Ice-O-Matic F6 mean?

F6 on the Ice-O-Matic CIM and ICE-series controllers reports a freeze / harvest sequence failure: the machine cycled through the harvest stages but did not detect a successful ice drop within the expected window. Common root causes are a defective cube-thickness probe (sometimes called a water-level / harvest probe), a sticking water-distribution tube clogged with mineral scale, a cam-switch out of adjustment on older units, or a hot-gas valve that is leaking through and warming the evaporator during freeze. Per the ICE0250–ICE2100 service manual, the diagnostic flow is to verify the cam-switch, then the water-regulating valve, then the harvest probe before considering a control-board fault.

How are ICE-series cubers different from GEM Pearl Ice flakers?

Ice-O-Matic ships two distinct ice-machine families with different fault patterns. The ICE-series cubers (CIM, ICEU undercounter, ICE0250 through ICE2100 modular heads) make full or half-dice cubes via a vertical evaporator, water-distribution tube, and cube-thickness probe — they expose the LED-pattern + F/E/HI/LO code family covered above. The GEM Pearl Ice flakers (GEM0450 and similar) make small chewable nuggets via a horizontal auger inside a refrigerated cylinder and have their own auger-torque, bin-thermostat, and gearmotor diagnostics rather than the cuber's freeze / harvest backup-timer codes. Always confirm the family on the nameplate before mapping a fault to a code table.

How do I reset an Ice-O-Matic ice machine after a fault?

On most Ice-O-Matic ICE-series cubers, the manufacturer's documented reset is to remove the front service panel (two Phillips screws at the base), then press and hold the Power button and the Clean button simultaneously for three seconds — the LEDs flash blue and yellow to confirm the reset. Press Power once afterwards and both LEDs should return to solid blue for normal operation. A reset on a still-faulted machine just re-trips on the next cycle, so always identify and fix the root cause (dirty condenser, clogged filter, failed thermistor, scaled evaporator) before resetting; otherwise the controller will simply latch the same F/E code again within minutes.

When should I clean an Ice-O-Matic ice machine?

Ice-O-Matic recommends a full descale-and-sanitise cycle at least every six months on most ICE-series and GEM machines, and more often (every three months) in hard-water installations or high-throughput foodservice sites. Indicators that cleaning is overdue include slow ice production, hollow / soft / cloudy cubes, the F5 cleaning-required service code on CIM units, and a slow yellow flash on the Clean LED. Use only Ice-O-Matic-approved nickel-safe cleaner and follow with a sanitiser rinse — household descalers and vinegar can void the warranty and damage the nickel-plated evaporator surface.

When should I call an authorised Ice-O-Matic technician?

DIY tasks for Ice-O-Matic owners and on-site maintenance staff include condenser cleaning, water-filter replacement, the documented Clean cycle and reset for F5, and clearing accumulated bin ice that has triggered the bin-full thermostat. Call an EPA-Section-608-certified refrigeration technician for any HI / LO fault that returns after the basic checks (sealed-system diagnosis, leak repair, brazing, TXV replacement), for repeat F6 / E5 / E6 faults that survive a thermistor swap, for any code involving the control board itself, or whenever the unit is still under Ice-O-Matic factory warranty — unauthorised sealed-system repairs void coverage on the entire refrigeration circuit.

Quick Answer

Ice-O-Matic ICE-series cubers and GEM Pearl Ice flakers diagnose faults through front-panel LED indicator lights plus F-prefix (faults — F5 cleaning, F6 harvest), E-prefix (errors — E5 thermistor, E6 water/condenser probe), and HI / LO (high or low pressure / temperature / water) service codes. Reset by holding Power + Clean for three seconds after fixing the root cause.

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Ice-O-Matic Troubleshooting Assistant

Q: What does Ice-O-Matic E5 or E6 mean?

On Ice-O-Matic ICE-series cubers, E5 typically points to the harvest / freeze-cycle thermistor or evaporator probe being open, shorted, or out of range — the controller cannot terminate freeze on temperature and trips a fault. E6 typically reports a water-system or condenser-side probe / float fault: insufficient flow at the inlet valve, a stuck water level float, or a remote-condenser water-regulating valve out of adjustment. Diagnostic flow: ohm out the suspect thermistor disconnected at the board against the model's resistance-vs-temperature table, verify water flow from the inlet, then check the cam-switch and water-regulating-valve adjustments per the service manual before considering board replacement.

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By Nichita Herput

Co-founder & CEO · Reviewed May 2026

What error codes does Ice-O-Matic display?

Cleaning-required service code on CIM-series — Power LED solid red, Clean LED slow-flashes yellow about once every six seconds. Run the documented descale-and-sanitise cycle, replace the inlet water filter, then hold Power + Clean for three seconds to reset.

Freeze / harvest sequence failure — the machine did not detect a successful ice drop within the expected window. Check the cube-thickness probe, water-distribution tube for scale, cam-switch adjustment, and hot-gas valve for leak-through before considering a board fault.

Cam-switch / water-regulating-valve adjustment fault per the ICE0250–ICE2100 service manual; verify the cam-switch contacts and the water-regulating valve setpoint before checking refrigerant charge.

Machine-does-not-enter-harvest fault — check the purge valve, suction-line temperature, and the freeze-termination thermistor along the documented service-manual flow chart.

Water-trough level / ice-bridge thickness fault — confirm the water trough is filling to the correct level and that the ice bridge is forming to spec; adjust the water-regulating valve and verify the harvest probe.

Harvest / freeze thermistor open, shorted, or out of range — ohm the suspect probe disconnected at the board against the model's R-vs-T table and replace if out of spec.

Water-system or condenser-side probe / float fault — insufficient inlet flow, a stuck water level float, or a remote-condenser water-regulating valve out of adjustment.

Cube-thickness / harvest-probe fault on ICE-series cubers — the controller cannot detect ice bridging across the probe; clean mineral scale, verify probe wiring, and replace the probe if the resistance is out of spec.

High-pressure / high-discharge-temperature trip — most commonly a dirty air-cooled condenser, a failed condenser fan motor, blocked rear-cabinet airflow, or starved water-cooled supply. Clean the condenser and verify fan rotation before resetting.

Low-pressure / low-water trip — either the low-pressure refrigerant cut-out has opened (loss of charge, frosted TXV) or the inlet water supply has fallen below the minimum. Confirm water pressure first, then attach gauges before calling for sealed-system service.

Common questions about Ice-O-Matic equipment

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