DIAGNOSIS This is almost always a power supply or outlet issue, not a dead unit. Check the basics first.
FIX Ensure the power adapter is firmly plugged into the port on the back of the purifier AND into a working wall outlet. Try a different outlet in another room. Listen for a faint click when you press the power button.
IF THAT DIDN'T WORK Inspect the power adapter cable for any kinks or damage. Try a different 36V DC power adapter with the correct polarity if you have one, but the official one is recommended.
HEADS UP The Core 300 has no physical power switch; it's all via the touch panel. If the outlet and cable are good and it's still dead out of the box, contact Levoit for a replacement—it's likely a defective unit.