This product, Honeywell RTH2310 has the WORST install user guide I have ever come across because of the following points:
1. There is no discussion as to how to wire up older two wire thermostats - one black and one white wire.
2. There is no description on hoe to remove the front plate so you can access the wiring terminals - there is a reference to it as you reassemble the thermostat after you have installed it.
3. Missing totally is how to change the display temperature form Fahrenheit to Centigrade and this involves a call to customer support.
Get with the program Honeywell and write usable manuals with your products or has the art of writing died?