Answers · Ice that comes out wrong
Why Are My Ice Cubes Hollow?
The short answer
Sub-Zero ties hollow cubes to low water pressure, a spent filter or a dirty condenser, and the first two begin with checks an owner can make.
Check in this order
- Fit a new Sub-Zero cartridge if the water filter indicator is showing.
- Switch the unit off, reseat the cartridge fully, then switch it back on.
- Open the fridge's shut-off valve all the way: try the next cabinet, a nearby sink or the basement.
- Replace any in-line or whole-house filter feeding the fridge once its date has passed.
- Note when the condenser was last cleaned; Sub-Zero's Classic guide wants it done every six to twelve months.
Past this line it is a technician's job Sub-Zero Repair Tacoma, (206) 472-1140
Behind the answer
The ice maker opens its water valve for a set fill, so anything that slows the flow puts less water in the mold, and the cube comes out thin or empty in the middle.
Where the house runs on reverse osmosis or a private well, Sub-Zero’s answers raise a pressure booster or regulator. That is plumbing ahead of the fridge, not a part inside it.
Related questions
Can I test the water pressure at the fridge myself?
Sub-Zero offers no gauge or procedure for checking water pressure and sends owners to a plumber. Depending on the model, the supply has to hold between 20 and 100 psi or between 35 and 120 psi, and on reverse osmosis it must also stay steady.
When do hollow cubes need a technician?
When a fresh Sub-Zero filter has had a day, the valve is fully open, any in-line filter is new and the cubes still come out hollow. Then the fill and pressure get measured at the unit. Sub-Zero Repair Tacoma takes that call 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