text: 310RL. A couple three times over the last 7-8 months we'll find we're "out of propane", but when i go out and check the tanks one is empty and the other is at least half full, or more. The black selector switch is always straight up which pulls from both (assume?). I flip the switch both ways and then back to middle position and gas seems to flow normally again. Do these things go flaky, especially after a couple cold winters?
  With the auto change over regulators leaving the lever in the center should pull from both tanks. They are made to have the lever pointed towards one tank or the other. It will allow that tank to empty then auto switch to the other tank. Just check the window on the regulator and if it’s solid red it has changed over. Flip the lever to the other tank and take the empty to get filled.