EC 15 on Sub-Zero’s Undercounter Wine Storage series indicates a sealed-system problem — confirmed directly by Sub-Zero’s own support documentation.
Step 1: Power-Cycle the Breaker
Turn the home circuit breaker for the unit off for 30 seconds, then back on, and retest — Sub-Zero’s own recommended first step.
Step 2: Understand What “Sealed System” Means
This points to the compressor, refrigerant charge, or condenser fan — not a sensor or a seal — which is a meaningfully different (and more involved) repair category.
Step 3: Why This Isn’t DIY Territory
Sealed refrigeration system work legally requires an EPA-certified technician, and continuing to run a unit with a genuine sealed-system problem risks further compressor damage.
Step 4: Book Service
If the reset doesn’t clear it, visit our wine storage repair page — our technicians are EPA-certified for exactly this category of repair.