Fuel reserve solenoid valve

[mikebro]

I've got the fuel reserve unit out of the tank, cleaned, stripped down, reasembled and tested. It works, but I would like a second opinion on exactly how. As found, and as rebuilt mine seems to work as follows (simply connected to a battery, not via the car's wiring):-

No power on - both long and short inlet tubes open to outlet.
12volts on - only the short tube open to the outlet.

What this suggests is that power goes on when the ignition is on and so only the short tube is open to the outlet. Pulling the reserve switch with the ignition on drops the power thus opening ther long tube to the outlet as well as the short tube. This would work, but is not what I was expecting which was that power on or off would change over from short to long tube. I was also expecting to have to put power on to bring on the long tube.

Anyone know how it is supposed to work?