Error code reference

Sub-Zero Refrigerator Error Code 20

Defrost under-heat with no voltage feedback through Gray/White wire at defrost start.

SourceSub-Zero UC-24 Refrigerator - Service Manualp. 3-20, 8-2, 8-4

Sub-Zero codes Sub-Zero refrigerator codes

Diagnostic procedure

The full 20 procedure

Step 1 is visible so you can confirm you are on the right page. The remaining steps, the ones that tell you whether to actually replace a part, unlock with any pass.

MyPros+ · DiagnosticsStep 1 preview

First diagnostic step

With cold evaporator (<10°F/-12°C), initiate Manual Defrost, then initiate Diagnostic Mode and observe evaporator temp; if temp exceeds 45°F (7°C) and defrost lasts longer than 5 minutes, error is false: clear it. Otherwise check continuity of Grey/White wire from defrost heater to J2 on control board.

SourceSub-Zero Original: Prior to Serial 3603000: Service Manualp. 8-2, 8-4

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Where this code is documented

27 manuals in the MyPros+ library document this code for Sub-Zero refrigerator.

Models covered by the manuals that document this code

More models are covered than are listed here.

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The full 20 procedure

Where this code is documented

Models covered by the manuals that document this code

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