Haven't been here in a while but thought I'd throw up an update.
When we did a walk through the day we bought this, the dealer service tech said he'd make sure the unit was winterized before we picked it up. Cool, one less thing to worry about.
That was in late September. When I finally got the repaired unit home in early November I didn't really think that much about it. A few days after I got it home we had a pretty good cold snap. Guess what? When it finally occurred to me to check, I found a 1/3 full water tank frozen solid. I opened the drain and faucets and turned the furnace on and set it to 82 and let it sit for a few days, then was able to blow out all the lines with the exception of the kitchen sink. I was never able to get air out of those lines, but hopefully they'll be ok come spring.