Answers · Ice that comes out wrong
Why Are the Cubes Getting Smaller?
The short answer
Smaller cubes mean less water reaches the mold at each fill, and Sub-Zero's lists point first at a tired filter and at low water pressure.
Check in this order
- Check the cartridge's age: Sub-Zero's Classic guide rates it for 750 gallons or a year, whichever comes first.
- Replace it if the indicator is lit or it is past that; discard the first ice.
- Turn the fridge's shut-off valve fully open, especially after any work under the sink.
- Swap out an expired in-line or whole-house filter upstream of the fridge.
Past this line it is a technician's job Sub-Zero Repair Tacoma, (206) 472-1140
Behind the answer
Each harvest is eight cubes, every two to three hours. A short fill leaves that count alone and shrinks each cube, so the bin looks busy while the pieces get smaller.
No panel button fixes it. Max Ice, on Classic, Designer and PRO models, only speeds production up; the fill setting is a service adjustment.
Related questions
Are small cubes the same as a slow ice maker?
Not quite. Sub-Zero expects an empty bin to take one to two days to fill, so a slow bin can be normal. Cubes visibly smaller than they used to be are a separate sign, and Sub-Zero's troubleshooting ties that one to the water side.
Could the ice maker itself be the cause?
Yes, once the filter, the valve and the pressure are ruled out. Sub-Zero lists a water valve not working properly and an incorrect fill setting among ice maker faults, and neither is an owner job. Sub-Zero Repair Tacoma tests both; book on (206) 472-1140.
- Signed
- Marta Fennimore
- Role
- Refrigeration technician — ice systems and water supply
- In the trade
- 12 years
- Holds
- EPA 608 certified
- Checked
- Sep 18, 2026