Sub-Zero Classic BI Code 10-R-00: open thermistor on the fresh-food coil

What 10-R-00 means

Classic Built-In models with electronic control, the BI-36U/S being one, display 10-R-00 when the refrigerator evaporator thermistor is open. This sensor is attached to the refrigerator cooling coil and reports coil temperature to the board, which needs it to manage defrost on that side. With the circuit open, the board loses the coil reading. Ice can gather behind the refrigerator rear panel, and the fresh-food section may start to feel less cold.

Common causes of 10-R-00

An unplugged refrigerator evaporator sensor
A wire break close to the refrigerator coil
An open refrigerator evaporator thermistor

✓ One safe check you can try

1. Check the refrigerator section temperature with a thermometer on a middle shelf. 2. Look for frost or ice on the rear panel. 3. Reset the breaker once. 4. If the reading rises above 40 degrees, move dairy and meat to a cooler.

! Why to stop there

The sensor is behind the refrigerator evaporator cover
Ice near the coil hides thin refrigerant tubing
We need to confirm defrost works on both sides 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.

→Same appliance

Other Refrigerator codes

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 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

10-R-0010-R-00 questions

What is the R in 10-R-00?

On the Classic BI, R stands for the refrigerator evaporator. The F codes cover the freezer coil. So 10-R-00 means the refrigerator coil sensor circuit is open.

Why is my refrigerator side warming?

Without a coil reading, defrost may leave ice behind. That ice blocks airflow, so the fresh-food section slowly loses cold. We clear the ice and restore the sensor circuit.

Is the repair covered?

Our labor carries a 30-day workmanship warranty. Before we start, you get a written price that includes the sensor or plug if one is needed, plus the time to clear any ice.