Summit freezer display briefly shows dF or "DEF" and cooling pauses.

Information: The dF/DEF indication on many Summit digital freezers is normal and simply means the unit is in a defrost cycle.

What to do:

• Do not unplug the freezer: Allow the defrost cycle to complete. It typically lasts 15–30 minutes.
• Check for excessive frost: If dF appears very frequently and frost builds up on shelves or walls, there may be an underlying defrost or door seal issue. Inspect the door gasket and ensure the door is closing properly.
• Monitor temperature: The interior temperature may rise slightly during defrost but should return to normal once the cycle ends.

When it's a problem: If the unit seems stuck in defrost (warm interior, compressor never runs), then the control or defrost circuit may be faulty and should be diagnosed as in the E3/E4 scenarios.