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killybeggs · Jan 6, 2007, 06:16 PM

I am trying to install a Honeywell programmable 7400 "universal" thermostat.

My current system does not match the wiring colors on the 7400.

Current system is a trolatemp by honeywell. The terminal colors are: WROBGY This is an oil forced air heat and AC system with 2 zones.

The terminals on the for a non heat pump system are:
RC R W Y G C Y2 W2

What goes where?

Any help greatly appreciated. Honeywell is closed and it's going to get pretty cold tonight with no heat.

Thanks:)

NorthernHeat · Jan 7, 2007, 08:08 AM

I need to know where all the wires connect at the furnace since installers don;'t always follow the rules. Typical non-heatpump connections are. Red wire to Red and jumpered to Rc. Green to G, White to W, and yellow to Y. A lot of installers use Blue for Y, something you will have to figure out.

T-Top · Jan 7, 2007, 07:22 PM

I agree with northenheat no one wires the same. R and RC should have a jumper if only one transformer is being used. (most of the time the red wire ) . G, is the blower wire (green), W or W2 (white) is the heat, Y (yellow wire) is cooling. Blue black or brown may be common ( C ). Need moore info gas heat - heat pump or what.