My new TT has tank heaters with are thermostatically controlled however there is a warning that says there must be liquid in the tank do not turn when tank is empty. I would think its the sam for a Class A
Depends on the coach. Some are automatic and will come on when the outside temp reaches a certain temp...providing you have the furnace or Aqua Hot on. Otherwise, manually turn it on when the temps will be freezing.
What kind of heater. Our last trailer that electric tank heaters that wouldn't come on until it got cold and then they would shut themselves off if not needed.
Will take it a while to decode "NWFL" but if you are near, we have 60F weather. No worry about freeze. My brother in Baltimore area got snow up to his deck railing, so that would be different story.