Sub-Zero UC-24 Code 08: freezer evaporator thermistor

What 08 means

On UC-24 undercounter models with a freezer section, the UC-24F and UC-24CI for example, code 08 tells you the freezer evaporator thermistor read open, shorted for 10 or more seconds, or kept reporting temperatures that did not add up. That sensor tracks the freezer cooling coil and guides defrost. Built-in 600/700 refrigerators also print 08, yet their chart is separate from the undercounter one. Owners usually notice frost or ice building inside the freezer, longer run times, or a slow loss of cold.

Common causes of 08

A freezer evaporator sensor connector that is loose or wet
Sensor wire damaged by ice or rubbing near the coil
A freezer evaporator thermistor that has failed
A control board that misreads a good sensor

✓ One safe check you can try

1. Check the freezer for thick frost on the back or floor. 2. Make sure the freezer door seal is not torn or folded. 3. Do not chip ice from the back wall. 4. Restart the unit at the breaker after one minute off. 5. If ice keeps building or 08 shows again, book service.

! Why to stop there

The coil and its sensor are behind a panel near refrigerant tubing
Sharp tools used on ice can puncture the coil
Defrost and sensor checks need a meter and a temperature reference

Opening a panel yourself does not automatically cancel a manufacturer warranty, but it can cause accidental damage, and some manufacturers set their own service conditions. Check your warranty terms, or ask us, before deciding.

→Same appliance

Other Undercounter & Drawers codes

05Sub-Zero UC-24 Code 05: refrigerator cabinet sensor reading 06Sub-Zero UC-24 Code 06: refrigerator evaporator sensor issue 07Sub-Zero UC-24 Code 07: freezer cabinet thermistor reading 22Sub-Zero UC-24 Code 22: no defrost voltage feedback 23Sub-Zero UC-24 Code 23: defrost overheat without feedback 50Sub-Zero UC-24 Code 50: refrigerator compressor runs too long 21Sub-Zero UC-24 Undercounter Code 21: defrost overheat EE + Service flashingSub-Zero UC-24 Undercounter EE with "Service" Flashing: temperature sensor problem

0808 questions

Why does my UC-24CI freezer keep icing up with code 08?

The evaporator thermistor tells the control when to defrost the coil. If it reads open or shorted, defrost does not happen on time and ice builds up across the coil and back wall.

Is code 08 different from code 07?

Yes. Code 07 is the freezer cabinet sensor that measures air temperature. Code 08 is the freezer evaporator sensor on the cooling coil. They sit in different places and are tested separately.

What will the repair include?

We clear the ice safely, test the sensor and its wire, and confirm a defrost cycle runs. The price is written before work, and the repair carries our 30-day workmanship warranty.