How to clean a commercial ice machine
Cleaning is the single most effective repair on a commercial ice machine. Scale is behind most of the faults owners pay technicians for, and the manufacturers spell out exactly how to remove it. The details differ by brand, and the differences matter.
Wear liquid-proof gloves and goggles — Hoshizaki's instructions require both. Never use ammonia-based cleaners, which Hoshizaki warns can damage the machine. Never mix descaler and sanitiser: Manitowoc says to keep them separate. Don't leave the machine unattended with its panels off.
Cleaning and sanitising are two different jobs
- Descaling (what manufacturers call "cleaning") uses an acid-based cleaner to dissolve mineral scale from the evaporator, water trough, pump, sensors and distribution tubes. Scale is what makes ice stick, floats jam and sensors misread.
- Sanitising kills the bacteria, slime and mould that grow in the water system and bin.
Every manufacturer runs them as separate cycles, cleaner first, then sanitiser.
How often
| Brand | Manufacturer's minimum | Notes |
|---|---|---|
| Hoshizaki (KM) | At least once a year | Much of the industry works to every 6 months. Air filters every 2 weeks |
| Manitowoc | At least every 6 months | Air filter monthly |
| Scotsman (Prodigy) | At least twice a year | De-scale reminder defaults to 6 months of power-on time; can be set to 4 |
| Ice-O-Matic | Descale at least twice a year, no more than monthly | Sanitise after every descale. Hard water: set the reminder to 3 months |
These are floors. Hard water, a hot room, and kitchens with flour, yeast or grease in the air all need more. Manitowoc adds a useful rule: if a machine needs cleaning more often than every six months, have the water tested. Frequent scale is a water problem, and filtration costs less than ever more frequent cleaning.
Which cleaner
Each manufacturer names its own products and amounts. Use the one your manual names, at the quantity it gives:
| Brand | Descaler | Sanitiser |
|---|---|---|
| Hoshizaki | Hoshizaki Scale Away — 14 fl oz into the water tank on a KM-340 to KM-901 | Plain chlorine bleach, no additives — 0.78 fl oz on the same models |
| Manitowoc | Manitowoc liquid descaler (#000005162), or powder descaler packets for modular cubers. Flakers and nuggets use the separate Metal Safe descaler (#000005164) | Manitowoc liquid sanitiser (#000000084), or powder rinse packets |
| Scotsman | Scotsman Clear 1 scale remover — from 8 oz on a C0322 to 24 oz on a C1448–C2648 | As your manual specifies |
| Ice-O-Matic | The products and quantities in your model's manual | |
Older Manitowoc manuals list cleaner 9405463 and sanitiser 9405653; the current product guide uses the numbers above. Hoshizaki's sheet also gives a stronger mix for badly scaled machines: 5 oz of Scale Away per gallon of warm water.
What "nickel-safe" means, and why it matters
Many cube machine evaporators are plated — Manitowoc describes its modular cubers as having electroless nickel evaporators. The plating gives the ice a smooth surface to slide off at harvest. An aggressive cleaner can attack it, and an evaporator that has lost its plating holds onto ice. That is a very expensive part to damage with a cheap bottle.
"Nickel-safe" cleaners are formulated for plated evaporators. Nu-Calgon's, a citric and phosphoric acid product introduced in collaboration with Manitowoc, is labelled for all makes including nickel- and tin-plated evaporators. With no manufacturer instructions, Nu-Calgon gives 5 fl oz per gallon of system water, and 3 oz per gallon for soaking parts. But if your manual names a product, use it: Manitowoc tells owners to use only its own descaler and sanitiser.
Step by step
The order is the same on every brand. The buttons and timings differ, so keep your model's cleaning instructions to hand.
- Empty the bin. Remove all the ice — Hoshizaki's first step. On a dispenser, dispense the remaining ice and turn the dispenser off.
- Start the clean cycle and add the descaler to the water trough or tank when the machine calls for it. See the brand notes below.
- While it runs, soak the removable parts — water curtain, distribution tubes, trough where removable — in a descaler solution, and scrub with a soft nylon brush. Manitowoc's remedy for a scaled ice thickness probe is a 10-minute soak in cleaning solution, then sanitising. Avoid wire brushes on the evaporator.
- Rinse. Flush the descaler out completely before sanitising. Mixing the two produces a chemical reaction, not a stronger cleaner.
- Sanitise: run the sanitising cycle with the sanitiser added, and wipe or spray the bin, the inside of the cabinet and the parts you removed. Manitowoc says to wait 20 minutes after refitting parts before starting the sanitising step.
- Reassemble, close any cleaning valve, and return to ice making. On Hoshizaki KM models, the cleaning valve must be closed for normal ice making.
Brand by brand
| Brand | How the cycle runs |
|---|---|
| Hoshizaki KM | Switch to ICE for 3 minutes, add Scale Away, switch to WASH for 30 minutes. Sanitise on WASH for 45 minutes. Rinse: ICE 3 minutes, then WASH 5 minutes. Cleaning valve open for cleaning and sanitising, closed afterwards |
| Manitowoc | Clean and sanitise cycles take about 24 minutes each. Wait 20 minutes after refitting parts before sanitising. Never use high-pressure water jets |
| Scotsman Prodigy Plus | One-button clean: press Clean, it harvests for 3 minutes, drains, then pauses for you to add scale remover. About 35 minutes in all. Older Prodigy machines use a manual two-step process |
| Ice-O-Matic | Use the Clean button and follow your model's manual. The clean reminder is set by a switch: switch 3 ON changes it from 6 months to 3 |
Machine not making ice after a clean? The usual culprits are a curtain not refitted, a cleaning valve left open or the switch left on Clean; ice machine not making ice has the full checklist.
The parts a quick clean misses
- Water level sensors and float switches. Scale on these causes some of the most common fault codes: a scale-jammed float on a Hoshizaki gives three beeps, and scale bridging the probes on a Scotsman lights Sump Full with no water. See our Hoshizaki and Scotsman guides.
- Air filters. Hoshizaki: every two weeks. Manitowoc: monthly, with mild soap and water.
- The condenser. A clogged condenser stretches every cycle and works the compressor harder.
- Water filters. Scotsman says every 6 months, sooner if pressure drops. Ice-O-Matic extends its evaporator warranty to 7 years for machines on its filter programme. See ice machine water filters for sizing and the gallon limit.
- The bin. Scotsman says to sanitise it as often as local health codes require and every time the machine is cleaned. The FDA treats ice as food.
Signs it's overdue
- Cycles getting longer. A clean Scotsman cycles in 11–13 minutes at 70°F air and 50°F water. A machine that is slower than it used to be is usually scaled or has a dirty condenser.
- Ice sticking to the evaporator, or harvests taking longer.
- Water-related fault codes: float, water level and fill errors, long-freeze faults.
- Visible scale: white crust on the trough, curtain or distribution tubes. Pink or black slime means sanitising is overdue — see mold and pink slime in an ice machine.
Is it worth paying someone?
Routine descaling and sanitising is well within a trained staff member's reach and is the owner's responsibility under every major warranty — none of them pays for cleaning. 86 Repairs notes manufacturers recommend at least two preventive maintenance and deep-cleaning visits a year. A sensible split is in-house cleaning on schedule, with a technician's preventive maintenance visit once or twice a year to check what you can't see: the refrigeration side, the condenser and the controls. Scotsman's warranty excludes failures caused by not cleaning and maintaining the machine as its manual sets out, so keep a dated log.