Sub-Zero Designer Code 10-1-10: Zone 1 coil sensor circuit open

What 10-1-10 means

Sub-Zero Designer integrated units, including the DET3050CI and DEC3050R, use 10-1-10 to report an open Zone 1 evaporator thermistor. This sensor sits on the cooling coil and tells the board when frost has cleared during defrost. With the circuit open, the board loses that signal and has to guess when to end defrost. Owners may notice nothing at first, then see frost building on the coil cover or Zone 1 slowly losing cold.

Common causes of 10-1-10

A loose plug at the Zone 1 evaporator thermistor
A wire broken near the coil, where ice and movement stress it
An open Zone 1 evaporator thermistor

✓ One safe check you can try

1. Check the back panel of Zone 1 for frost buildup. 2. Keep the door closed and the seal clean. 3. Do one breaker reset. 4. If frost is heavy, unload food into a cooler before the visit. 5. Do not chip ice off the coil cover.

! Why to stop there

The sensor is clipped to the coil behind the rear panel
Chipping frost can puncture refrigerant tubing
Defrost timing needs to be verified after the fix

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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Other Refrigerator codes

41Sub-Zero 648PRO Code 41: Zone compressor or wiring problem 81Sub-Zero 700-2 Code 81: Variable-Speed compressor fails to start 82Sub-Zero 700-2 Code 82: VS compressor controller needs replacement 88Sub-Zero 700TF Code 88: Board and compressor controller not talking 80Sub-Zero 700TF Code 80: No inverter feedback after a board change ddSub-Zero 600 and 700 Series Display dd: Diagnostics switched off deSub-Zero 600 and 700 Series Display de: Diagnostics enabled 23Sub-Zero 600, 700 and 648PRO Code 23: Defrost overheat with no feedback

10-1-1010-1-10 questions

What does an evaporator thermistor do?

It reads the coil temperature so the board knows when defrost has finished. Without it, defrost may end too early or run too long, and Zone 1 cooling suffers over time.

Why is frost building after 10-1-10 appeared?

With the coil reading lost, defrost cycles can stop short and leave ice behind. That ice blocks airflow, which is why Zone 1 slowly warms. We repair the sensor circuit and clear the frost properly.

Can I melt the frost myself?

Keeping the door closed and unloading food is fine. Please do not pry or chip ice from the coil area; the tubing is thin. We melt it safely during the visit.