Honeywell stat wiring w/ Trane furnace
 

I have a Trane XV90 two-stage furnace. I just purchased a Honeywell RTH7600 Thermostat and I'm unsure if I have the wiring correct.

When I unhooked the old thermostat, there were wires to the Rc(jumpered to R),G,Y and W terminals. There was an unused, unlabeled blue wire as well. When I looked at the board on the furnace, there were wires to the W2/W1(jumpered)(W), R(Rc), G(G), B/C(unused), and Y/YLO(jumpered)(Y) terminals (I put the corresponding thermostat terminals that the wires were hooked to in parentheses there).

When I hooked the new thermostat up, I made all the corresponding connections just as they were before - to W, Rc, G, and Y, and I also hooked the previously unused blue wire to C.

Then when setting up the thermostat initially, I told it I had a two-stage furnace.

So, my questions are:

1. Since the blue wire was previously hooked to nothing at the thermostat site, should I move it from C to W2 at the furnace and un-jumper W1 and W2? Then obviously I'd hook the blue wire to W2 at the thermostat.

OR

2. Should I just tell the thermostat I have a one-stage furnace and let the furnace decide when it needs to kick into the 2nd stage?

Thanks. I know at least part of this was confusing, so please have me clarify if needed.

r to r, y to y, g to g, w1 to w1, w2 to w2, If you need a common at the t-stat leave the w1 to w2 jumper and use extra wire b/c to t-stat common.
if you are you using the comfort R variable air flow for the a/c you need to jumper the y to o
(not Ylo) and r to bk. Then set up the dip switches properly for comfort R.

The outdoor condenser will hook up to Y and b/c The a/c wiring is assuming you only have a single stage a/c

Well, the B/C (as labeled at the furnace) was just dangling and hooked to nothing at the thermostat before, so I would assume I don't need it (the system seemed to work fine before). So I could move the wire that's currently hooked to B/C at the furnace to W2, unjumper W2 from W1 at the furnace, and then hook this wire to W2 at the thermostat?

Just one-stage cooling, so I think I can leave all the Y business alone - and I'm not sure what the "comfort R variable air flow" is anyway.

Thanks. :)

There are 2 wires from the outdoor a/c one is to thy Y termonal what is the other hooked to?

Here is a discription of the option. Note if you use this option and have a older a/c it may be possable to damage the compressor. It is a very nice option but can involve risk with a older units.



Trane's exclusive Comfort-RTM feature represents the ultimate in comfort. The Comfort-RTM feature gives you greater humidity control in cooling. In this mode air moves over the coil more slowly at start up. This allows the coil to rapidly cool down resulting in increased moisture removal. The Comfort-RTM feature also gives you a warmer air start-up in heating with a heat pump. • Quieter Operation
• Better Filtration
• Enhanced Humidity Control
http://www.texastrane.com/images/humidity_chart.gif

Exspecially if they're overcharged to begin with.

Nope - brand new unit outside as well. I'll try to decipher the spaghetti of those wires - I did ID the two coming in from outside but it's hard to follow them after that.

Just to confirm though, on the heat issue (it is January, after all :wink: ). Is this the correct thing to do:

Like I said, my other option would be to tell the t-stat I have one-stage heating and let the furnace figure it out.

It will improve your comfort, using the stat to control staging.