We often would take our old trailer snowmobiling. It had NO extra insulation and open bottom tanks. It never froze as long as you kept the heater inside at a reasonable temp. We kept ours in the mid 50's.
I did have to put some lights on the valves when I got home once to let them thaw a little but it wasn't that big a deal.
We were driving through Oregon one spring. A crazy cold front came through Klamath Falls and dropped temps to single digits and snowed. That 6 hour trip froze all the water lines up and it took us about 4 hours blasting the heater with all the cabinets open to thaw the water lines but no damage.
These lines are pretty durable for short cold snaps
Chris
