FIELD CAS-4 COMBUSTION AIR SYSTEM

Howdy! Thank you for posting your query about the Honeywell TH3210D1004 thermostat. To change the batteries, first, remove the thermostat assembly from the back mounting section by applying even pressure. Second, remove the AA alkaline batteries and replace them with the new one. Please pay attention to the positive and negative marking, in order to install the batteries in its proper direction. Lastly, reinstall the thermostat assembly. You may refer to this installation guide for more information. Thank you for choosing PlumbersStock. Have a great day!

Hi! Thank you for your query about the Honeywell TH3210D1004 thermostat. No, the batteries are optional. It provides backup power to the display in case of power interruption. Please see page 9 operating manual for more information. We hope this helps. To order, simply click the "Add to Cart" button once you get there, fill in the required fields, and we will take care of the rest. Thank you for trusting PlumbersStock. Have a great day!