Care · Seasonal
Descaling an Undercounter Ice Machine on Los Angeles Water
An undercounter ice machine spends its life wetting the same surfaces: water under pressure, a spray into inverted cups, a harvest, a drain. Whatever the supply carries in dissolved mineral stays behind on those surfaces, and mains water here is not soft.
Written byElena Sandoval
- Role
- Refrigeration technician — cabinet, door and seal work
- In the trade
- 24 years in the trade
- Certification
- EPA 608 certified
Scale rarely stops a machine outright. It slows the spray, leaves the cups shallow and turns clear cubes cloudy, so the bin fills later every week and nobody can say when it started. The cure is a cycle the machine already has built into it, run with the cleaner Sub-Zero makes for it and nothing else.
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Clear the evaporator first
Touching CLEAN starts a two-minute harvest that drops whatever ice is still sitting on the evaporator. Doing it in this order means the cleaner meets metal rather than a half-frozen slab of last night's production.
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Empty the bin
Take every cube out of the storage bin. The guide asks for that before anything reaches the spray area, and an empty liner is far easier to wipe down while the cycle runs itself.
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Wait three minutes, then four ounces
When the CLEAN light flashes, lift the water shutters and pour four ounces of undiluted Sub-Zero ice maker cleaner straight into the spray area. Use nothing else, and keep it off your skin: the manual for the older 315I says plainly that this cleaner contains acids.
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Let the whole cycle finish
A ten-minute clean runs, then eight rinses, roughly half an hour in all. The CLEAN light goes out when the machine is satisfied. Cutting it short leaves cleaner in something that is about to make ice.
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Run the sanitiser the same way
Touch CLEAN again, wait the three minutes, and add a tablespoon of sanitiser at the shutters. Same ten minutes, same eight rinses. This is the half of the job that gets skipped.
While you are down there
How often does the machine actually need this?
Sub-Zero asks for a clean and a sanitise every six months on the UC-15I, and its guide adds that poor water quality can mean doing it sooner. The filter runs to the same six-month mark. If yours is closer to quarterly before the cubes clear, ring LA Sub-Zero Repair Pros on (310) 919-2538.
Does a water softener help with mushy cubes?
No, and Sub-Zero says so directly: softeners are not recommended for its ice makers. The older 315I manual goes further, warning that on a very hard supply a softener tends to give soft, white cubes that clump in the bin. Have the water tested and treated for what it actually carries, rather than for a guess.
Where the figures come from
- Sub-Zero UC-15I(P) Ice Maker Use and Care Guide — the cleaning and sanitising sequence, the six-month interval, and the water filter count
- Sub-Zero Models 315I and 315IP Operations Manual — the acid content of the ice maker cleaner, and what softened water does to cube quality