Ice Machine Won’t Stop Making Ice
When your ice machine won’t stop making ice, it keeps harvesting batch after batch even though the bin is already full — and instead of shutting off, it overfills the bin until cubes jam the chute, melt over the door, and pool water across your floor. This fault shows up on every style of commercial ice maker we service: Hoshizaki and Manitowoc modular cubers feeding a separate bin, Scotsman flakers and nugget machines, undercounter self-contained units behind the bar, and large half-batch and full-batch cubers in busy kitchens. Armus Refrigeration diagnoses and repairs ice machines that won’t shut off for restaurants, bars, supermarkets, c-stores, and schools throughout New Bedford, Fall River, Dartmouth, and the rest of Southeastern Massachusetts and Rhode Island. Because an overflowing bin wastes water and energy every hour and creates a slip-and-sanitation hazard, we treat it as urgent — we are EPA-608 certified, available 24/7, and rated 5.0 on Google.
What’s likely happening
- The bin thermostat or bin sensor that is supposed to read “bin full” and end the cycle has failed, so the machine never receives the signal to stop and keeps making ice.
- On mechanical-bin-thermostat machines, the sensing bulb or capillary has lost its charge or drifted out of calibration, so it reads “empty” even when the bin is packed solid with cubes.
- A float switch or water-level/bin-level float has stuck in the down or “call for water” position, holding the machine in a continuous run instead of letting it cycle off.
- The control board has a stuck relay or failed output, energizing the compressor and water valve nonstop regardless of what the bin control is telling it.
- An infrared or thermistor-style bin sensor is fouled with mineral scale, slime, or splashed water, so it never “sees” the ice stack and keeps the machine harvesting.
- The bin-full sensing path is mechanically blocked — a bent ice deflector, mispositioned curtain, or cubes bridging past the sensor — so full ice never interrupts the beam or pushes the paddle.
- Miswired, shorted, or corroded control wiring between the bin thermostat, float switch, and control board is sending a constant run signal even though every component looks fine.
What Armus checks & fixes
- We confirm the symptom first — verify the bin is genuinely full and the machine is still harvesting — then trace whether the run command is coming from the bin control, the float switch, or the control board.
- We test the bin thermostat with a meter: check resistance/continuity as we cool the sensing element, and replace a bin thermostat or bin sensor that won’t open its contacts when ice is present.
- We inspect and free the float switch — clean scale and slime off the float, verify it travels freely and the contacts make and break, and replace a stuck or corroded float switch or water-level assembly.
- We clean the bin-full sensor on infrared or thermistor machines, clear any ice bridging or curtain/deflector misalignment blocking it, and confirm a full stack now triggers a clean shutoff.
- We diagnose the control board by checking that the shutoff input from the bin control actually de-energizes the compressor and water-valve outputs; we replace a board with a welded relay or dead input rather than chase ghosts.
- We check the wiring harness and connectors between bin control, float, and board for shorts, corrosion, and chafed insulation, and repair anything sending a false continuous run signal.
- We run the unit through several complete freeze-and-harvest cycles, fill the bin to the sensor, and confirm the machine shuts off and restarts correctly before we leave — and we descale the water system if scale was the root cause.
Why this happens
Every commercial ice machine runs a freeze-and-harvest loop: the evaporator builds a slab or batch of cubes during the freeze cycle, then a hot-gas valve diverts hot discharge refrigerant back across the evaporator to warm it just enough to release the ice into the bin. That loop is only supposed to repeat until the storage bin fills. The component that ends it is the bin control — either a mechanical bin thermostat with a sensing bulb mounted in the bin, or an electronic bin sensor (thermistor or infrared) — which tells the control board “bin full, stop.” When the machine won’t stop making ice, that shutoff signal is missing or being ignored, so the loop never terminates and the bin overfills.
On Hoshizaki and similar mechanical machines, a bin thermostat senses the cold of ice piling up against its bulb and opens its contacts to halt the cycle. If the bulb loses its refrigerant charge, the capillary kinks, or the thermostat drifts out of calibration, it never opens — the machine reads a perpetually “empty” bin and keeps harvesting. On electronic machines, a thermistor or infrared bin sensor does the same job, but mineral scale, slime, or a splashed lens can blind it so it never registers the full ice stack.
The float switch plays a parallel role on water management and, on some designs, bin and water-level sensing. A float that sticks down — usually from scale buildup or a sliming sump — keeps calling for water and keeps the unit running. Hard water is the common thread here: Southeastern Massachusetts and Rhode Island water leaves heavy scale on floats, sensors, evaporators, and water valves, and that scale is frequently what jams the very component that is supposed to shut the machine off.
Finally, the control board ties it all together. Even a perfect bin thermostat and a free float can’t stop a board with a welded relay or a failed shutoff input — the board keeps the compressor, hot-gas valve, and water valve energized regardless. A real diagnosis has to separate a stuck mechanical sensor, a fouled electronic sensor, a stuck float, miswiring, and a failed board, because each one looks identical from the front of the machine: a bin that keeps overflowing with ice.
Equipment we service
We repair this on every type of commercial refrigeration:
How we fix it — our process
- Confirm and observe: we verify the bin is actually full and the machine is still cycling, watch it run through a freeze-and-harvest, and note exactly when it should have shut off but didn’t.
- Test the bin control: we check the bin thermostat or bin sensor with a meter — resistance, continuity, and whether it opens when ice/cold is present — and inspect for scale, slime, ice bridging, or curtain/deflector misalignment fooling it.
- Check the float and water side: we inspect the float switch for stuck travel and contact failure, clean off scale, and confirm it makes and breaks correctly.
- Verify the control board: we confirm the shutoff input de-energizes the compressor and water-valve outputs, and check the wiring harness between bin control, float, and board for shorts or corrosion.
- Repair and descale: we replace the failed bin thermostat, sensor, float switch, or control board, and descale the water system if hard-water scale was the underlying cause.
- Verify the fix: we run several complete cycles, fill the bin to the sensor, and confirm the machine shuts off and restarts on its own before we leave.
Service area
Armus Refrigeration handles ice machine won’t stop making ice for restaurants, markets, c-stores, schools, and commercial kitchens across New Bedford, the South Coast, the South Shore, Cape Cod, Greater Boston, and Rhode Island — including:
Frequently asked questions
Why won’t my ice machine shut off?
Why is my ice bin overflowing?
Can a bin sensor or bin thermostat be replaced same day?
Is it safe to keep running an ice machine that won’t stop making ice?
Could hard water be making my ice maker run nonstop?
Brands We Service
We repair and maintain every major commercial refrigeration & ice brand.