I do not trust solenoid valves for a critical function like fuel selection.
The problem is that most fuel valves eventually need rework, lube
wears away, o-rings get stiff, etc.  WIth a manual valve you assess
the condition each time you use it, and if it takes a bit more force,
the "bit more" is available (within reason) - you just twist harder.
At some point, you are aware that the valve needs work, and
hopefully, you fix it before you can't switch tanks at a critical time -
like over Monterey Bay at 300 ft..

With an electrically actuated valve, it just stops working one
day.  Probably at the worst possible time and you crashland
with lots of unusuable fuel.   Part of the reason that John Denver
is dead is that the builder of his plane was so worried about
fuel fwd (pusher) of the firewall that he remoted the fuel valve,
leading to a linkage located at the left shoulder point which
requires contortions and the right (control stick !) hand in a
Long EZ to select tanks.  I have heard that the valve handle
had been temporarily replaced with a set of Visegrip pliers.
Valve so stiff it broke the handle?  Don't know.  Apparently
ran a tank dry and failed to control the A/C while struggling
with a poorly located and possibly stiff, non-std fuel selector
design.

I bought a certified A/C (Piper) valve.  Andair makes very
expensive but extremely nicely made fuel valves of many types.

Bill

Thanks, Bill

The solenoid valve would be for the return of fuel to one or the other
tank.

I was thinking about a seperate pump and filter for each tank and the
electric controlled valve to direct fuel back to the tank.

If one went bad, the other could be used.(Hopefully enought to get to
the next airport)

I could run a manaul contol valve and lines for fuel return up to where
I sit to control back to the tank, but more plumbing!

Wayne Peterson

How would you monitor the failure of the valve Wayne?

Paul Lamar

What are other builders doing with the fuel after the fuel rail?
Wayne Peterson

Send the return fuel back to the tank you got it from with a manually
operated dual valve. Safest and most tried and true system.
As bill pointed out a solenoid valve can fail at a critical moment
such as take off and you would not have time to trouble shoot the system
or operate a back up.

BTW I was flying a Mooney with fuel injection and the back up pump failed
causing the main pump to fail and the engine to stop. The take off 
procedure was turn on the boost pump which is sort of a back up pump. 
The electric boost pump vanes failed and a particle stuck in the engine 
mechanical pump causing the engine to stop with a bang. Fortunately I was able
to dead stick it in. My point is.... backups don't always work
automatically. You need to keep the fuel system as simple and as reliable 
as possible. That sometimes means buying expensive parts such as the Andair dual
fuel valve. If you switch tanks you should also switch fuel pumps at 
the same time. This also means never take off with one empty tank.

Unfortunately fuel injection, mechanical or electronic, will 
never be as simple or reliable as a gravity feed carburetor.

Paul Lamar
 
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