How to Change the Battery in a Honeywell Thermostat
Honeywell thermostats are highly regarded for their advanced design and exceptional reliability, making them popular choices for home HVAC systems. These don’t normally have a lot of performance issues, so replacing the batteries is likely to be one of the only maintenance tasks you’ll need to handle. If you’re looking for instructions on how to do so, this guide on how to change the battery in a Honeywell thermostat explains the process from start to finish.
This guide is for Honeywell Home TH6210U2001 T6 Pro programmable and RTH111 non-programmable thermostats, as well as FocusPRO™ models, such as the TH5110D and TH5220D non-programmable units.
Supplies
- 2 AAA Alkaline Batteries
- 2 AA Alkaline Batteries (FocusPRO™ units, except the TH5110D)
The low battery warning message appears about two months before the batteries die completely. Even if the warning doesn’t appear, be sure to install new batteries at least once a year, or before leaving home for more than a month.
Directions
- Step 1. Turn off the HVAC system - Reduce the risk of short circuits or accidental activation of the system by powering down your heating and cooling system before proceeding.
- Step 2. Access the old batteries - Reach the old batteries by pulling at the bottom of the wall plate on Honeywell Home units and then flipping it over. For FocusPRO™ models, press down on the tab at the upper right-hand corner to release the battery compartment and then pull it out.
- Step 3. Remove the old batteries - Pull the existing batteries out of the unit. Be sure to check local regulations on how to dispose of used batteries.
- Step 4. Position the new batteries - Place the new batteries into the back of the wall plate on Honeywell Home units and into the battery holder for FocusPRO™ models. Remember to orient them properly based on the + and - signs.
- Step 5. Install the batteries - Reconnect the wall plate to the wall mount on Honeywell Home models and reinstall the battery compartment on FocusPRO™ units.
- Step 6. Check the installation - Turn the HVAC system back on using the thermostat switch. If the display lights up, the batteries are installed correctly. If not, double-check the orientation of the batteries and ensure they’re fully seated.
- Step 7. Restore the settings (if needed) - Reset preferences if necessary. Most settings are stored in permanent memory, so only the day and clock should need to be adjusted. Refer to your owner’s manual for detailed instructions on how to do so.
- Step 8. Resume normal operation - You may now use the thermostat normally.