Deep Chill, Did it freeze my beer

[mwilks]

I have a Kegco 309 and it has a deep chill mode. I put a fresh keg and put it on deep chill for about 20 hours. Came in to tap the keg and I had frost on my CO2 and keg. Thermometer I put in the kegerator was reading 30 degrees. Its pouring fluid beer and all. Just wondering if I could have frozen my beer or messed anything up? This is only my second keg. First keg took what seemed forever to get to a good temp so I used the deep chill this time. Any opinions are appreciated.

[djc]

Shake the keg. Does it sound like slush?