How do I know if the batteries are low? 18 November 2021 11:29 Updated If batteries are low, the Smart Valve LED light will start flashing yellow and you will receive a notification from the app. Related articles How do I replace batteries? Smart Valve Installation and Configuration Wizard Where should the Smart Valve be located? How does the Smart Valve work? How can I change the room temperature via the Smart Valve? Comments 0 comments Please sign in to leave a comment.