I am trying to install a new Honeywell model number rth221b. I have 4 wires coming out of my wall. One white, one red, one blue, and one green. How do I wire this thing. I tried by what a friend told me but my heater won't come on.

White red and Green are in your instructions that came with your thermostat but the blue does not jive with the regular color schedule. What kind of furnace are you trying to wire to?