From the furnace what are the blue, white, green, red wires

The c in the furnace that is white is going to your condenser, it must stay. ADD the blue that goes to the tstat OR brown, which ever and then use that color on your new tstat and you will be fine. Always turn power off when changing stat

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you have to go to the furnace and match up the 4wire tstat wires to the thermostat so for instance say
RED-RED 24v
White-White heat
Green-Green fan
Blue-Blue will be Y for cooling

measure the voltage on coil of od contactor should be 24 volts

This is if you have gas furnace and central air conditioning.
Normally this is the way.
Red wire to R (or if your stat has Rc and Rh, wire to both of these
White wire to W
Green wire to G
Yellow wire to Y
Blue wire to C
If you want to check, before you connect to stat. Connect red and white (heat should come on)
the connect red and green (blower should come on) Normally yellow is for air conditioning and Blue is common DO NOT CONNECT ANY WIRE DIRECTLY TO BLUE, if blue is common it would short out fuse

In most cases, the wires are used as this: Red=Power, White=Heat, Green=Fan/Blower Motor, Yellow=A/C. The other wires, like the one hooked to the yellow will be the condenser wires going outside. The thing I'm not sure on, is that Honeywell Thermostats usually have the terminals marked with R,W,B,G,etc. If it does, then the wires will be as color coded and just hook them back up that way. You can also test to see if those wires are what they are supposed to be by jumping the wires. You can start with red since that is supposed to be your 24v power. Jumper red and green, you should get the blower motor on, jumper the red and white, you should get the heat to come on. Same goes for a/c as explained above. Any other questions, I will be glad to help.

I can give you a start, For heat only, R terminal on furnace to Red wire to R or RH terminal on thermostat. W terminal to White wire to W terminal on thermostat. G terminal to Green wire to G terminal on thermostat. This will get you heat but not air conditioning.

Red: Power (24 Vac) Green: Fan White: Heat Blue: Common
Now I would check those at the furnace BEFORE you hook the wires up.

For heat pumps........


R = Red wire (hot24v)
G = Green wire (blower motor)
Y = Yellow wire (AC condensor)
C = blue wire (common)
O = Orange wire (reversing valve)
W1 or W2 = White wire (emergency heat)


For gas furnace


W1 = white (gas furnace)
R = red
G = green
Y = yellow
C = blue

Try this.

A T-stat.

Orange = O
Red = R (with existing jumper)
Black = C
Yellow = Y
White =W1 (Or AUG)
Green =G

At airhandler/furnace.

Green = blower wire (usually green, double check with schematic)
(Green should not go to the HP.)
Orange to HP
Red to red and to HP
black to blue (or C) and to HP
White to W
Yellow to HP. (It may also go to a "float switch" if installed. but that will just be a safety switch on the drain pan in case the line clogs and it overflows.)

The green is typically used for the blower motor. (furnace only)

The orange is used for the reversing valve. (changes from AC to heat, is located in the HP only)

Blue is typically used for common (or "C") but they may have changed it to black due to a broken wire, or other problems.

The only wires going to the HP should be
Red
Blue/black
orange
yellow

Orange should not be going to the furnace at all.

HP wiring should be
Orange to orange or O
Red to R or red
Blue/black to blue or C
Yellow to Y

the normal wiring for stats is white=w=heat,red=r=24volts,green=g=fan,blue=c=common,yellow=y=cooling.
see what ties into your furnace board and match the terminals.