3 sourced reports, with what to check before you buy. Each one links to the page it was reported on.
Costly or dangerous
Control panel/knob defect at 8 months — air fry mode won't set
An owner of an 8-month-old Double Stack reports the knob will not set air fry mode; the expert concludes a defect in the control panel or knob mechanism after standard troubleshooting failed.
What to check. If the mode-select knob stops responding within the first year, do not attempt DIY repair — file a warranty claim with SharkNinja promptly, as this appears to be a control-board/knob defect rather than user error.
Non-stick coating wears away rapidly even with plastic utensils and hand washing
A Spanish-market reviewer of the SL400EUCP (same Double Stack XL platform) reports the non-stick coating wearing away rapidly even with plastic utensils and hand washing only, including at the drawer edges that slide into the housing.
What to check. Treat the non-stick surface as fragile: avoid metal utensils, avoid dishwasher use, and inspect drawer edges regularly. If coating peels within warranty, claim replacement — this is a known surface-wear complaint on the Double Stack XL platform.
E error code — unit not functioning properly, requires service contact
The official SL400 manual (Azerbaijani edition) states an 'E' message on the display means the unit is not functioning properly and directs the user to contact customer service — indicating a recognized fault state requiring service.
What to check. If 'E' appears on the display, do not attempt reset loops — contact SharkNinja customer service directly, as the manual itself directs service contact for this error.
These reports come from the pages linked under each item: owner forums, repair guides and workshops. They are not a diagnosis of any one unit, and a careful check of the one you are buying still applies.
Text from the Kriko Air fryers catalog, version 0.1.2, under the CC-BY-SA-4.0 license.
