PRODUCT UPDATE:
Update as of 12 SEP 2024
The customer should be able to see the UV light in a dark black room.
They need to open the panel, remove the filter, and turn the unit on.
The UV light needs to warm up, so after a few seconds, and with the filter door still open, they should see a bluish green glow coming from the bottom of the unit where the base of the filter would be.