Ok, I've done this before...but I screwed up this time:rolleyes: I desided to change over to a Programable thermo, and just unhooked everthing and didn't pay attention to where everything was.:banghead:

So I know I started with 4 wires hooked up to

RC, W, G, and Y

Wire colors are Red, White, Green, and Blue

I hooked it back as

Red to RC/RH (has jumper)
White to W
Green to G
Blue to Y


Now the fan blows but the condenser dosn't kick on, so no cold air:( What happened? Did I blow something?

This for a Lennox HVAC system.

Breaker was not triped:rolleyes:

...It depends...:scratch:

...Did you turn off the breaker first...If you didn't you may have blown a fuse or a reset at the unit itself..;)

I did turn the breaker off first yes;) Where would the fuse be? On the condencer or the unit itself?

...Depending on a bunch of variable's, the easiest way to usually find it is at the power into the unit...It is required to have a quick disconnect at the unit...It may be a breaker in a box or a quick "pull" disconnect...

..If it has a quick "pull" disconnect, what is left in your hand when you pull it, usually will hold 2 fuses...One of these usually will fail if the breaker was on...

..If you don't find a breaker or quick disconnect as required, sometimes the equipment will have a disconnect at the inside of the service panel...

...Thats about it for me ..and the direcions for the T-stat's will generally tell you your wiring procedure and if you need the jumper or not.....:dunno:

Y should go to Y so you might check to see if its in the wire wrap, just cut short so you cant see it. Last time I checked, Blue was used as a power wire from the furnace to the tstat so you didnt have to use batteries. Hook the yellow up the yellow, and see if that helps. Blue is just a common and unless it is connected at the furnace (most 4 wire situations are not) it will not do anything. The red jumper is needed, let it be

i have no yellow:(

In the furnace on the main board, what is the blue hooked to? There should be two sets of tstat wire coming in, one will just have two wires (red and white typically) the second will have 4 (from tstat). Tell me what all 4 are connected to.

There are only 4 wires at the thermostat. Blue, Green, White and Red.

I'll have to check the actual unit.

ok...Blue wire went to a tan wire that looks like it goes to the condenser I hooked this to Y

Is it working?

There is a board inside of the furnace where all the wires meet. Is this tan wire (prob an old yellow) that you are talking about there? A pic would help

It just a rats nest of wires:rolleyes: I'm waiting to finish up getting a Washer/Dryer hooked up first in the closest next to it, before I turn it on again.

That rats nest is us HVAC guys way of making LOTS of money off of you guys ;)

So the A/C is working again. I'm not sure if it was wired wrong or what:rolleyes: Anyway, he said we needed two things.

1. a Low voltage disconect box.
2. a bigger breaker for the unit.

as long as it's working, I'm fine for right now though:(

IF wired but a normal person
Rc/RH Is usually red With a jumper One leg of the 24 volt
G Is green For fan
W is white and for heat
Y Is usually yellow For A/C
C is blue for common if your using a thermostat without batteries
or with batteries as a back-up



for a heat pump is different
Rc/Rh is red one side of 24volts
W is white is for heat
G is green is for fan
y is yellow isor A/C
O is ORange is for Crossover valve at Condenser
B is for black thermostat and goes out to condenser
C is either blue or black and is common from tramsformer