Hey all,
Got a new Carrier thermidistat fresh out of the box. Installed it on a 1-speed AC, gas heat unit (only 5 wires). When I plug the stat in, I get an "A" on the display initially (the docs don't say anything about just an "A") and then it says the temp is 7. I cannot do anything with it (set temp, time, etc.). It will not even go into programming mode. I set dip switch 4 to on (installer mode) but nothing happens when I press and hold the fan button for 10+ seconds (well actually when I let go, it turns the fan on).

I have previously installed 4 of these same stats and haven't had any problems.

The troubleshooting in the docs that come with it are pretty thin and don't address what I am seeing. I looked all over the internet and can't find anything else.

Any ideas? I am thinking the stat is toast and have already ordered another one, just want to see if there is anything I can do to get it going (maybe try to force it to factory defaults?).

Thanks in advance.