IMHO the dealer should have winterized the unit given the time of year.
Has it had water run thru the plumbing?
If it has then it should be winterized now unless you plan on using it this year or early next year.
If no water has been run thru the plumbing then some RV anti freeze should be dumped in the sinks toilet bowl and shower, the holding tanks should be as empty as possible.
With empty tank there is more than enough room for expanding water.
2016 F350 6.7L LB CC Reese 28K 2014 Chaparral Lite 266sab
"Those who would give up essential Liberty, to purchase a little temporary Safety, deserve neither Liberty nor Safety." 2014 19 days camping 2015 17 days camping201620 days camping