I just replaced my old Trane Weathertron (Baystat 339) mercury thermostat with a Honeywell RTH2410. Everything appears to be working fine, but I'm concerned about a few things... I had to tape off the Blue and Tan wires because there was no connections available on the new Honeywell. Also, the instructions told me to put both the Black (X2) and White wires into the Aux connector on the new Honeywell. Does that seem right? Should I have purchased a more expensive Honeywell thermostat where I would have separate connections for Black (X2) and White as well as somewhere to connect the Blue wire (instructions on more expensive Honeywell thermostats say to connect the Blue wire to "C").

Any thoughts? Here's the breakdown of which old wires I connected to the new Honeywell RTH2410:

R - R
O - O/B
Y - Y
G - G
X2 - W/AUX (combined with W)
W - W/AUX (combined with X2)
B - Taped off and tucked back into wall
T - Taped off and tucked back in to wall

I appreciate any help / advice you may be able to provide.

If everything is working and working right,, you are OK,,
The blue wire to c (common) is correct if the blue is connected in the furnace (this does away with the need to worry about replacing batteries ,no need for them

The batteries may be used for battery backup, alhough some stats have internal coin cells.