This article walks you through how to turn on the lamp function for the UKU. The lamp function must be turned on in order for the light in the sauna to power on. 

Follow these steps to turn on the "lamp" function on the UKU controller:

• Hold down the HUUM UKU button for 10 seconds to pull up the main menu
• Scroll down to vent/lamp and press the button to select
• Make sure the lamp is on. If not, press the button to turn it on.
• Go back to the main screen that displays the internal temperature
• There should be a sun icon in the bottom right hand corner of your screen
• Now double tap the home button and the sun icon should become bolder