The black lever switches between the two tanks. I had something similar but it had a different indicator. If you can ID the manufacturer, you can probably download the instructions. Here's a link to some images of different types that may help if there's no manufacturer name on it:
When it is green, there is propane in the selected tank (valve must be open). When it turns red, either the tank valve has been closed, or that tank is empty, and the regulator automatically switches to the other tank. As soon as you switch the selector, it will turn green again showing that the selected tank has propane, again, assuming it actually has propane in it and the tank valve is open. Then it is time to fill the empty tank so it will switch again when the other tank runs dry.
Plus, when you switch to the one remaining tank, it's a good idea to get the empty one filled so you always have a full tank in reserve. Don't wait until both are empty.
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Bob C
2002 Itasca Suncruiser 35U
Workhorse Chassis
Linear Mode
