Diagnosis
A solid red power button light indicates a filter installation or detection error. The unit's safety system has locked operation.
How to Fix It
Power off the unit and unplug it. Remove the front filter cover. Take the filter out completely. Re-insert the filter, ensuring the cloth filter sleeve's handle is centered and the entire filter is seated flat and straight against the back wall. Snap the cover back on firmly until all clips engage. Plug the unit back in and press the power button. The light should turn white.
If That Didn't Work
Inspect the black plastic filter frame for any cracks or damage, especially near the top center. A broken frame prevents proper sensor contact. You will need a replacement filter.
Heads Up
Never operate the purifier without a filter installed. The red light is a mandatory safety lock, not a suggestion.