Diagnosis
The unit has an auto-off safety timer. On some models and firmware versions, the Dehydrate function has a maximum run time limit (often around 4-6 hours) to prevent overheating during extremely long, low-power runs.
How to Fix It
For dehydration runs longer than the limit, you'll need to restart it manually. Set a timer for yourself just before the limit (e.g., 4 hours), check the progress, and press Start again to begin a new cycle. There's no way to disable or extend this timer.
If That Didn't Work
If it's turning off in significantly less time (like 30 minutes), the internal overheating fuse might be tripping due to blocked vents. Ensure the rear air intake and the top exhaust vents are completely free of dust, grease, or kitchen clutter.
Heads Up
Dehydrating creates a lot of moisture. Always use the provided mesh screen on the tray for anything with small pieces or liquids to prevent drips into the base. Never run it in an enclosed cabinet or right up against a wall.