Thanks. Troubleshooting will be tough as it was a one-shot problem and won't reproduce, but if someone is familiar with what circumstances could throw that particular error code, that'd be helpful.
My concern is having a 'hard failure' when I'm boondocking (often 3-4 days at a time w/ no AC) and thus no 50 amp for the heat pumps, and my wife is with me (she's not quite as amused with the 'joy' of troubleshooting problems with the coach :-)). Worst case I guess is I can still fire up the diesel generator to run the heat pumps, but that doesn't always go over well at night, since both genny and heat pumps are a lot noisier tha the furnace.
It was 58 degrees in the coach when I woke up after it threw the code, I'm just happy my wife wasn't on that trip with me :-)