Honeywell thermostat install quick question

[cheechi]

Found garage journal in a google search today, imagine that. this thread came up while I was looking up wiring for a thermostat.

Honeywell TH700D
old tstat says Trane TAYSTAT 241 (circuit diagram pdf)

Gas furnace is Trane XL 80 according to the manual
AC didn't find a model on it but I can check again if it's needed.

I have the following wires (per the old tstat, still installed)
Y1 - yellow wire
G1 - green wire
W1 - white wire
W2 - brown wire
R - red wire
B - blue wire

I think I need to wire the new tstat as follows

C - blue wire
G - green wire
Y- yellow wire
W - white wire
R - red wire jumped to Rc
W2 - brown wire

that's how it's labeled for 'conventional' but before I destroy the house I figured I would reach out for any available help.

Both breakers are off although I have not shut off the gas.

The Honeywell is not brand new, I bought it new but it was installed at an apartment and worked perfectly there. I only mention that because I don't have the factory jumper for R-Rc, I made one out of 16ga stranded Al wire which I assume should be fine for this application.

Honeywell wouldn't help because of the W1 & W2, all I really needed from them was to tell me where the blue one went but when they refused I hit the google and landed back here.

Thanks in advance.

 

[LS6 Tommy]

"C" and "B" are generally the same. "C" is Common, which is the Blue wire, hence the "B" notation on the new stat.

Tommy

 

[nehog]

... I don't have the factory jumper for R-Rc, I made one out of 16ga stranded Al wire which I assume should be fine for this application...

I would recommend not using Al wire. Find a bit of copper wire instead. 18 AWG would be the right gauge but for a jumper even 20 would work OK.

 

[Andyjman]

Usually its

R is red, thats the +24 that powers the stat
Y is yellow, thats the wire that turns on the cooling
G is green for the indoor blower motor
W is white thats your first stage of heat
W2 is your second stage of heat
B is usually brown and thatll be common, but sometimes they use blue

use a piece of t stat wire to jump between r and rc, youll be fine.

The old thermostats usually didnt use a common because the mercury bulb inside of them acted like an on and off switch thatdd make or break the connection between the r and the w or the r and the y depending on if you had cooling or heating enabled.

Its nice to be able to hook the common up on the newer digital stats because the stat will still work even if the batteries die, and if the stat has a back light provision, you can keep it on all the time and you dont have to worry about killing the batteries.

 

[cheechi]

Thanks. I got it wired up and working yesterday and actually had typed up a reply thanking the guys but who knows what happened to it.

Anyways, thanks all for the advice and I verified heat & cool both work after setting it up.

It is good to know what does what though, thanks for that.