Honeywell Thermostat code 0340-reset?
The contractor removed the Honeywell thremostat (it was not what I requested in our contract) and has installed the Trane TCONT800 theromstat. They both look almost the same and the solution to the my initial issue is the same ... you must have the "installation instructions" not just the owners manual. The installation instructions covers "ALL" those hinden codes. Be careful here, you really need to know your stuff before you go and change some of those options.
Briefly here's the steps to accessing those codes ...
1. press and release "system" key
2. Next you will see mostly blank buttoms at the bottom
3. Press the two (same time) on either side of the center blank buttom
4. Release, and the middle should have code 0120
Hope this helps.