Remove the front cover from the wall plate.

TYPE or MODEL Number is located on inside of front cover.

Links to additional information for 1F90 Series thermostats: 

• Replacement Homeowner's Manual/Installation Instructions
• Frequently Asked Questions (FAQ's) - 1F90-xxx Series thermostats

Quick programming guides for 1F90-xxx Series thermostats

• 90 Series 5+2/5+1+1 Day Models
• 90 Series 7-Day models