Thermostat or app indicates low battery; display may dim or become unresponsive intermittently.

Safety: No mains voltage is involved in battery replacement; it is safe for users.

• Install new batteries: Open the thermostat, remove old AA cells, and insert two fresh alkaline AA batteries from a reputable brand. Do not mix old and new batteries.
• Inspect contacts: Check the metal battery contacts for white or green corrosion. If present, gently clean with a cotton swab lightly moistened with isopropyl alcohol. Allow to dry fully.
• Check orientation: Ensure the + and − ends of the batteries match the markings inside the thermostat.
• Restart thermostat: After installing batteries, wait 1–2 minutes for the thermostat to reconnect to the Relay and app.

If low‑battery warnings return within days using quality batteries, the thermostat’s power circuitry may be faulty and the thermostat should be replaced.