REFLECTOR: Fuel Sump Sensor

[Ruben Creus]

Hi all,

 

Originally, I had a float type sensor in my sump tank. That is a sensor with
moving parts, so things like vibrations, position, and angle affect its
readings. That translated into false alarms. Eventually I realized that I
stopped paying any attention to the sensor at it was very unreliable; which
on the other hand is very dangerous as one day it might send a real low
level and I might dismiss it thinking it was a false alarm. So, I started
looking for a better solution.

 

After some research, I found and ultrasonic sensor with is rated for liquid
and includes gasoline. It is also ½ NPT, so very easy to swap for the
existing one. This is an epoxy device with a metal shield on it. Inside it
has and ultrasound emitter and receiver. The presence of liquid (in this
case fuel) creates a distortion in the ultrasound and that triggers the
sensor. The sensor can be ordered as a NO (Normally open) relay, which
closes when liquid is present.  (MODEL LVU-A716)

 

I am glad to report that I have experienced no more flickering or false
alarms. It works great on the ground while taxing, turning, at low RPM and
high RPM, flying even with nose up or nose down attitudes. It stays green
all the time. I guess that in the case of low fuel in the wings and in a
nose down it might let some air in the tank and that could trigger the
sensor, I will let you know if I see that, but it might take a while as I
rarely fly with low fuel on the wings. I also checked with low fuel on the
sump to confirm that it triggers the alarm when it supposed and it certainly
does. Differently than the float sensor, the ultrasonic sensor has no moving
parts. It sends an ultrasound. The ultrasound is not affected by vibrations,
or movement. If there is fuel there, it will signal it, if not it will not.
Simple and works.

 

Note that, this sensor requires power. I have fuel tank level sensors and I
had power already in the back of the plane, Very easy to install and wire.
In my case I have a Dynon EMS, so I had to change the configuration of the
sensor to be NO–Green and Closed–Red.

 

In case you are interested on knowing more about the sensor here is the link
to the manufacturer. 

http://www.omega.com/ppt/pptsc.asp?ref=LVU-A710_Series
<http://www.omega.com/ppt/pptsc.asp?ref=LVU-A710_Series&ttID=LVU-A710_Series
&Nav> &ttID=LVU-A710_Series&Nav

 

Let me know if I can be of any help 

 

Ruben G. Creus           
* +1.571.215.0025

*  <mailto:rcreus at vainneg.com> rcreus at vainneg.com

 

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