Model "AE Fuel Guardian"

A Low  Fuel  Annunciation  System designed for Aircraft





1.) Install the annunciator lights & switch in your instrument panel.

A.) Drill two holes for the lights, (0.625" dia.).  The lights measure 0.705" x 0.95", and protrude 0.35".

B.)  Install the switch.  Drill a 0.275" dia. hole.

B.) Affix the proper low fuel quantity lettering.


     Right & Left Tank                         Instrument Panel Lettering


Lettering can be easily inserted in the light's lens!


2.) Install the electronics.

A.) The electronics enclosure measures 3.5" x 2.25" x 1.25".  Find an appropriate spot under the instrument panel and install the enclosure using two #6-32 screws.  The centers of the mounting screws are 3.625" apart.  Easy wiring instructions are included!



3. Find the proper location for the sensor.   

A.) Position your fuel tank in the approximate "level flight position".

B.) Temporarily attach a clear plastic hose to the fuel tank drain cock.

C.) Fill the tank (with WATER to be safe) to your pre-selected, low fuel alarm quantity.

D.) Position the hose so that the top of the liquid in the hose, is closest to your internal fuel tank pick-up point.

E.) Mark the location for your sensor, near the top of the liquid level in the hose.


          Location #1                                       An Alternate Location


(Coloring had been added to the water for photograph clarity)

This gentleman has chosen a 3.0 Gallon alarm level for his right RV-6 tank.  It is exactly 20 minutes of flight left at 9.0 Gal/Hr.


4.) Install the optical sensors in your fuel tanks.

     (These instructions are for NPT type sensor threads!)


A.) Install a female threaded 1/4NPT bung on the inside or outside of the tank in your selected sensor position.  Make sure

      you seal the attachment points with "ProSeal" or equivalent fuel tank sealant.


B.) Using a "small amount" of "Fuel Lube" on the threads ONLY, it is to be screwed into a 1/4 NPT female fitting.  "Fuel Lube" should

       guarantee no leaks.  Sensor will malfunction if "Fuel Lube" is contacting the sensor tip.


             DO NOT over torque!!  13.26 in.-lbs. (1.5Nm) max.  It is NOT important that the sensor hex nut bottom out on the female fitting.


C.) After installing the sensor, we recommend using a small amount of "Pro-Seal" or another brand of fuel tank sealant to help secure

             the sensor in place. Applying a small bead around the outside of the sensor should guarantee it won't back out, and may also

             inhibit future leaks from forming. This suggestion is just a bit of extra insurance.



        Sensor measures 0.75" across flats of nut on the outside of the tank

        The sensor protrudes into the tank approximately 19.05mm (0.75 inches) max.

(Mount the sensor only horizontally, or vertically pointing up.  The reason for this is because you do not want to have any fluid drops on the end of the sensor when there is no liquid present.  This may give false readings.)



DO NOT put the sensor wires in any liquid, even for testing the system!  The wires may not be totally liquid proof on the outside of the sensor.  ONLY dip the tip of the sensor in liquid for testing the system.  Be sure not to scratch the tip of the sensor when handling it.


D.) Connect the sensor cables to the electronics.





User applied a small amount of "Proseal Sealant" (not shown) on the outside of the tank.

The 1/4NPT bung is also not showing in these photos.