Thermostat displays 'Low Battery' or beeps periodically

Safety first: No need to power down HVAC for battery replacement, but avoid shorting battery terminals.

Steps to troubleshoot:

• 1. Remove thermostat: Gently pull the Resideo thermostat straight off the wall plate.
• 2. Replace batteries: Install new, high-quality alkaline batteries of the specified size (often AA). Do not mix old and new batteries.
• 3. Inspect contacts: Check battery contacts for corrosion. Clean lightly with a dry cloth or pencil eraser if needed.
• 4. Reattach thermostat: Snap the thermostat back onto the wall plate, ensuring it seats fully.
• 5. Consider adding C wire: If batteries drain quickly, consult the manual about adding a C wire or C-wire adapter so the thermostat can be powered from the HVAC system.

When to call a professional: If the thermostat still reports low battery immediately after replacement, the battery holder or internal power circuit may be faulty and the thermostat may need replacement.