FS2520 Duplex Fuel Selector

The FS2520 is a 3 way Duplex Fuel Selector and allows for two lines to be switched simultaneously, this means that the return fuel from the engines fuel injector/manifold block can be returned to the same tank from which it was drawn.
The valve has the positions LEFT - RIGHT - OFF.

When the valve is in the ON condition, there is an easy action between the LEFT and RIGHT position. Inside the valve is are highly polished ball valves packed with precision PTFE seals. This not only provides a smooth action but also gives a perfect seal.

To switch the valve to OFF the red safety button on top of the lever must be raised. This helps preventing the pilot inadvertently switching the fuel OFF.

The FS2520 has a 1/2" feed section and a 3/8" return section. A variant of the FS2520 valve is used to supply engines such as the Continental IO-550-N and is used in the acclaimed Cirrus SR22.

Q: Why use an Andair Duplex Valve to return the fuel to the same tank from which it was drawn? Why can't I return it to a single tank. A: Returning the fuel to the same tank from which it was drawn does away with any potential over filling issues. If you return to a single tank, and you happen to be feeding from the other tank (perhaps the pilot is unaware of the fuel system layout) and that tank is full, you will start to dump fuel overboard. This is not a problem on short flights, however if you are doing a long leg, you could get a fuel outage.

On the FS2520 the lower section can only be used as the feed, and the upper section as the return. Each section is completely sealed from each other so there is no chance of any leakage from feed to return. The ports can be configured with any of the eight fittings that Andair currently manufacture, and this can be done during the ordering process. Also during ordering the fascia plates' engraving can be customised.