[Motor31]

I use the old warm water over the side of the tank trick to find out how much propane is in the tank. pour warm water over the side and then run your hand where the water was. The metal will be warm above the level of propane. If there is no cold line on the side, it is empty. If it is cold enough to form frost on the tank the frost will stop at the propane level in the tank in the daytime.

On my rig the switching valve points to one tank when it is draining that tank. It does not stay in the middle. When the tank runs dry it will switch over to the full tank internally so I still have to manually check the level myself. In the winter I keep a closer look at propane usage so I don't run out both tanks. I only open both valves when the main tank (in front so it's easier to move for filling) is almost empty so I don't lose heat at 0200 hours. The old 6p's saying comes to mind.