Sub-Zero Classic BI Code 10-F-00: freezer coil thermistor open

What 10-F-00 means

On electronic-control Classic Built-In units like the BI-36UFD/S, 10-F-00 means the freezer evaporator thermistor is open. That sensor sits on the freezer cooling coil and tells the board when defrost has melted the ice. With an open circuit the board cannot see the coil temperature, so defrost timing becomes a guess. In time frost may pile up behind the freezer panel and the freezer can lose some of its cold.

Common causes of 10-F-00

A disconnected plug at the freezer evaporator sensor
A broken wire near the coil, often where ice has stressed it
An open freezer evaporator thermistor

✓ One safe check you can try

1. Look for heavy frost on the freezer rear panel. 2. Make sure the freezer door closes fully and the gasket is clean. 3. Reset the breaker once. 4. If frost grows, transfer frozen food to a cooler with ice before the visit. 5. Do not scrape the coil area.

! Why to stop there

The sensor is clipped to the coil behind the freezer panel
Scraping ice can pierce refrigerant tubing
Defrost has to be confirmed after the sensor is restored

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 Refrigerator codes

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 50Sub-Zero 600 and 700 Series Code 50: Refrigerator compressor running too long 41Sub-Zero 648PRO Code 41: Zone compressor or wiring problem

10-F-0010-F-00 questions

Why does the freezer evaporator sensor matter?

It ends each defrost cycle. Without it the board may stop defrost too soon, leaving ice on the coil, and the freezer slowly loses airflow and cold.

Is 10-F-00 related to 10-R-00?

They are cousins. F covers the freezer coil sensor and R the refrigerator coil sensor on the Classic BI. Both 00 codes mean the circuit is open.

Do you melt the frost too?

Yes. We clear the coil safely, repair the open sensor circuit, and run a defrost to check that the coil clears completely. You approve a written price before we begin.