Remove the front cover from the wall plate.

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

or on wall plate

Links to additional information for 1F90 Series thermostats: 

• Replacement Homeowner's Manual/Installation Instructions
• Frequently Asked Questions (FAQs) - 1F90 Series thermostat Operation
• 1F92/1F94 Heat Pump Terminal Cross Reference
• 1F90/1F97 Isolation Transformer Installation Instructions
• Remote Sensor Troubleshooting Guide - F145-1049 and F145-1170

Quick programming guides for 1F90 digital programmable thermostats:

• 1F90/1F91/1F92, 5 + 2 Day thermostat models
• 1F94/1F97 7-Day thermostat models
• 1F95 7-Day thermostat model