Thermostatic Controls - Trouble With Display

I am having a very similar problem. Prestige thermostat replaced from hunter programmable (previously was old mercury type). Have elec lennox furnace (around 30 yrs old)

Only had 4 wires, instead of buying 5 to 4 wire module it seemed simple enough to just run new 5 wire.

At old thermostat
Blue to Y
Green to G
White to W
Red to RC

Had this at furnace:
Blue wire labeled R to Red
Red wire labeled W1 to White
Black wire labeled G to Green
Yellow wire labeled 3 & Brown wire labeled X to Blue

my assumptions:
label 3 means nothing is yellow wire
label x means common

Tried this at furnace:
Blue wire labeled R to Red
Red wire labeled W1 to White
Black wire labeled G to Green
Yellow wire labeled 3 to Yellow
Brown wire labeled X to Blue
And this at Prestige Thermostat
Red to RC (jumper to R)
White to W
Green to G
Yellow to Y
Blue to C

Got a blank screen

Tried to attach the 5 wire to previous hunter thermostat using 5 wire,, got a magical puff of smoke out of the furnace compartment, said some expletives, wired the old 4 wire back up to the hunter thermostat and now continuous smoke from transformer, said some more expletives, so I shut everything down, no power to anything.

Two questions:
what did I do to my furnace?
What am i doing wrong with hooking up the Prestige thermostat?

Two questions:
what did I do to my furnace?
What am i doing wrong with hooking up the Prestige thermostat?

1- Sounds like you burned out the transformer, and hope you did not do any damage to the t-stat.

2-I had a hard time following of what you were doing, and I'm lost.

I think you got 3 and X mixed up, and that what caused a blank screen, and then you hooked up the told t-stat and shorted out the transformer.

What is the model # on the furnace?

Do you have A/C on the furnace? If so, there should be two wires meeting up at the furnace.

1 wire joins Y from t-stat. 2nd wire goes to common on the furnace.

Jay11J
thanks for the reply, had a hard time finding the post after it was moved, did I post incorrectly in that old post, same model Prestige thermostat as original post?

Sorry if my post was confusing, I Switched a mercury switch to a programmable earlier in the year and then recently got given a thx9000 prestige thermostat and trying to hook it up.

The model number of the furnace appears to be "E12Q2-15-1P"
(found this "unit information" http://www.hvacpartsshop.com/E12%20Series.pdf)
I do have an A/C attached to this unit, not clear on your question about two wires meeting, sounds like my "Yellow wire labeled 3 & Brown wire labeled X to Blue" I can't figure out why the one is labeled "3" and the other "X". Which would you say is the common and which the Y?
I know there is a wiresaver module available "THP9045" but if cant figure out the common it would also be now help? http://customer.honeywell.com/techlit/pdf/PackedLit/69-2065EFS.pdf

The first part of my post is about the setup I had that was working previously.
"At old thermostat
Blue to Y
Green to G
White to W
Red to RC

Had this at furnace:
Blue wire labeled R to Red
Red wire labeled W1 to White
Black wire labeled G to Green
Yellow wire labeled 3 & Brown wire labeled X to Blue

my assumptions:
label 3 means nothing is yellow wire
label x means common"

Next i described what I tried to get new thermostat working:
"Tried this at furnace:
Blue wire labeled R to Red
Red wire labeled W1 to White
Black wire labeled G to Green
Yellow wire labeled 3 to Yellow
Brown wire labeled X to Blue
And this at Prestige Thermostat
Red to RC (jumper to R)
White to W
Green to G
Yellow to Y
Blue to C"

Any help is greatly appreciated,
Thanks

I moved your post to a new thread since your furnace is not the same as the the post you first posted this on.


I am going to ignore of what's is or was wired up to the furnace.

First thing you need to get is a new transformer since that went up into smoke.

Once you got the transformer replaced, we are going to wire up the t-stat the correct way. Keep the power turned off till we are done.


T-stat----------Furnace---------A/C
R/rc---red-----Blue(R)
W-----white---Red(W)
G-----green---Black(G)
C-----blue-----Yellow(C)------white
Y------yellow------------------red

I do not see #3 or X on the diagram that was on the file you posted for the unit itself.

So you may of shorted it out on one of those wires.