I had an old General Electric Weatherington thermostat. I bought a new one yesterday and this is the old and new wire setup.

OLD:
O
G
Y
R
B
W
X2.

New.
I've installed the R to the R and I kept the R and RC jumper since I own a heat pump with Aux heat.

The Aux Heat works but when it's in Heat mode I get cool air. I installed the "W"hite to the "E" and the "X2" to the "Aux". Could you let me know if this is correct. Not sure why it's blowing cold air, but in the setup for function 170 I've got it set to "7".

What brand of new thermostat and model number.

Honeywell RTH7400/7500 model

((I installed the "W"hite to the "E" and the "X2" to the "Aux".))

The white wire goes to the W on the new Honeywell.

The old X2 wire goes to the E on the new Honeywell.

See page 12 on this diagram.

http://customer.honeywell.com/techlit/pdf/PackedLit/69-1900EF.pdf

Sorry there Hvac, I had my stuff wrong actually the "White is going to the Aux and the old X2 wire is going to the "E". I took all the wires out and re splice them and it seems to be working just fine right now. Thanks for looking into this as well.