Propane tank valve

[ZeeLet50]

I have 2- 20lb tanks with the valve that can point to either tank or stay in the middle. There is the gauge that reads either green or red if the tank is full. When I put the valve in the middle,should I not expect it to be automatic and pull from one tank then when that empty pull from the other? When I put it in the middle position, I get no gas???. Am I doing something wrong here? There is propane in both tanks.

[MarkTwain]

Propane tanks-
What is purpose of the middle position? When should the middle position be used?

[the_bear_II]

X2 point the arrow at the tank...there is no middle.

[AirForceAngler]

I think these valves are designed to work with one tank or the other, not in the middle. They are designed so that when you have it pointing to one tank, it will draw from that tank till it's pressure drops too much (empty or near empty) then it will turn red and automatically draw from the other tank. The red is telling you to turn it till it points to the other tank and you can safely disconnect the empty tank for refill/replacement. Don't point it towards the middle.