Mailing List lml@lancaironline.net Message #62210
From: Charles Brown <browncc1@verizon.net>
Sender: <marv@lancaironline.net>
Subject: Re: [LML] Re: Fuel vent check valves
Date: Fri, 01 Jun 2012 00:12:51 -0400
To: <lml@lancaironline.net>
Be advised, the Andair check valve is probably not at fault.  They are designed to allow fuel and air to pass through *either* direction, only there's a very significant restriction to fuel *leaving* the tank.  When you think about it, this has to be so ... If you top the tank and you have a good cap that seals well and the fuel selector is OFF then as the fuel expands (if it warms up), it *must* go out the vent.  I bought a new Andair valve and tested it, that's when I learned this.

My Legacy RG also vents fuel from the left tank only, and I *think* that fuel also siphons right to left even on level ground - though I *could* be wrong about that.  At any rate, I leave it a couple of gallons down unless I'm just about to take off on a long cross-country.

The best comment I heard on this, which I haven't checked out, is to make sure that the vent line leaves the tank in an uphill direction.  Granted there's precious little room for that, but if the line leaves the tank downhill it seems to present a potential for siphoning.

Charley Brown
Legacy RG #299
110 hours


On May 31, 2012, at 12:09 PM, Bill Bradburry wrote:

Thanks, Steve.
 
That is what I expected should happen.  I sent an email to Andair a couple of days ago but no response so far.  I was asking them for ways to test the check valves in place.  They are not the easiest thing to access to remove.  I plan to try to test them today.  Probably a vacuum cleaner with the fuel caps off??  I want to be careful about pressurizing the tanks.  That is why I hoped to hear from Andair…
 
Bill B
 

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