Wiring diagrams for Honeywell thermostats can be found on the Honeywell website by entering the thermostat's model number and viewing the PDF version of the owner's manual, which contains wiring instructions and diagrams on wiring. Wiring diagrams may also be found on websites such as DIY House Help.
When purchasing a new thermostat, buyers may want to ensure that the new thermostat requires the same amount of wires as the old thermostat. Some newer model, programmable thermostats use 5 wires or more. Any additional wires required for the new thermostat need to be installed before attempting to install the device itself, or it may not work as it should.
When searching online for a wiring guide, thermostat owners should be sure to search using their model number. It may be helpful to label wires when removing them from the old thermostat, as they may differ in color from those referenced in the new thermostat's wiring guide. To install the new thermostat, simply connect the labeled wires with matching letters on the new thermostat's terminal. To do this, loosen screw terminals on the thermostat, and insert stripped wires into appropriate slots. Tighten all screws, and push the excess wire back into the wall.