I have a thermostat that has labels, not letters eg: 7.5, heat, cool, fan etc. The wires going to the thermostat are not your standard colors. I know what each of my wires are for, but I need to know what the letters represent on the back of my new Honeywell rth221. I know G means green, but what part of the system is it for? I need to know this for each of the letters.

Thanks everyone.

G blower activation
R power
W heat
Y cooling

If able to , I would open Air Handler and check what the Letters corespond too.
Red is common from transformer, Mostly I see White for Heat, Green for Blower Fan, Blue for Cool, or Yellow.

I see I'm a slow typest.