I had this Lenox furnace installed, but since the install the humidifier have not been working, when the furnace was installed we also had an icomfort thermostat installed also. I check the power coming out of the furnace for the humidifier and there is no power when the furnace is running. Can someone please let me know what you think is wrong?

Are you sure the humidifier got reconnected when the furnace was changed out? If not, I would call back the installer.