I replaced the weathertron baystat240 with the honeywell 7400. Taped off the brown (T) cable and the rest went in their corresponding letters. After setting up the system nothing happens.
It does not run. My system is a trane XE1000 Heat pump

Was the brown wire being used in your baystst240? If so trace it back to your air handler what was it attached to? If you need it and don`t have a place in the 7400 for it, you`ve probably can`t use the honeywell tstat,, also check to see that you haven`t blown the transformer,, hope not

WMproop Thanks for your answer.
Yes the brown was used on T. What I found out is that the fuse was blown so that is why it did not work. I replaced the fuse and now it is working properly.
I have one more question I'm planning on changing the Baystat 305 which only has 4 wires coming in. Which programmable thermostat would you recommend?