Sub-Zero Classic BI and Designer Code 10-2-00: freezer or Zone 2 thermistor reads open

What 10-2-00 means

Sub-Zero uses 10-2-00 on Classic Built-In models such as the BI-36U/S and on Designer units like the DET3050CI. On the Classic BI it means the freezer cabinet thermistor is open; on Designer it means the Zone 2 thermistor is open. The control loses the reading for that space and switches to a timed fallback, so freezer or Zone 2 temperatures can drift and ice cream may soften or items may overfreeze.

Common causes of 10-2-00

A loose plug at the freezer (BI) or Zone 2 (Designer) thermistor
A wire pulled apart behind the freezer liner
An open thermistor

✓ One safe check you can try

1. Put a thermometer in the freezer or Zone 2 and check it after two hours. 2. Keep the drawer or door shut and make sure it closes fully. 3. Reset the breaker once. 4. If 10-2-00 returns, pack frozen food tightly or move it to another freezer.

! Why to stop there

The thermistor is mounted behind the freezer liner
Probing wiring requires power on and panels off
A failed reading can come from the board as well, which needs testing

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.

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10-2-0010-2-00 questions

Does 10-2-00 mean my freezer is warming up?

Not always. The board runs on a timed backup, so the freezer may stay cold for a while. Check with a thermometer; anything above zero degrees Fahrenheit is a reason to move food.

Why does Designer say Zone 2 instead of freezer?

Designer models number their compartments as zones, and Zone 2 is the second one. The Classic BI simply calls it the freezer. Both readings are open.

What warranty do you give on the fix?

Our workmanship is covered for 30 days. Before any work, we explain which part of the sensor circuit is open, what it takes to fix, and give you a written price to approve.