Electronics International FL-1 - Manual (Page 23)

FL FL FL FL FL-2 F -2 F -2 F -2 F -2 Fuel Level Instrument uel Level Instrument uel Level Instrument uel Level Instrument uel Level Instrument
and and and and and
F FF FFuel Level System Issues uel Level System Issues uel Level System Issues uel Level System Issues uel Level System Issues
Getting a fuel level system to operate accurately is not always an easy task. The FL-2 solves many of the
problems found in standard gauges, but there are still many issues that must be addressed. These notes
will cover some of those issues.
Resistive F Resistive F Resistive F Resistive F Resistive Fuel Level Sensor Issues uel Level Sensor Issues uel Level Sensor Issues uel Level Sensor Issues uel Level Sensor Issues
It’s a good idea to test the resistance of the fuel sensors before installing the FL-2RA Instrument in the
aircraft.
A. For Resistive Fuel Sensors which decrease resistance when fuel is
added perform the following tests:
1. With the float at the bottom of the tank (as it would be if the
tank was empty), measure the resistance of the fuel sensor.
The resistance should be between 270 ohms and 90 ohms. If
the readings are below 90 ohms or greater than 270 ohms, you
may be using the wrong type of sensor. Use a sensor which decreases resistance when fuel
is added and which has a maximum resistance of between 90
and 270 ohms.
2. With the float at the top of the tank (as it would be if the tank
was full), measure the resistance of the fuel sensor . The
resistance should be near 0 ohms.
3. As you raise the sensor float slightly slightly slightly slightly slightly off the bottom of the tank, the resistance should start
to decrease. If it does not, the sensor resistance is probably topped out. The FL-2 will
read lower than actual fuel levels until the sensor wiper drops onto the resistive element.
With the sensor float held to the bottom of the tank, adjust the sensor float arm so the
wiper is on the resistive element and not on the termination (end stop). You will need an
ohmmeter to determine this. As you slightly move the float arm, the resistance should
change.
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By: Ron Roberts By: Ron Roberts By: Ron Roberts By: Ron Roberts By: Ron Roberts 0718971A 0718971A 0718971A 0718971A 0718971A Rev. A: 10/15/01 Rev. A: 10/15/01 Rev. A: 10/15/01 Rev. A: 10/15/01 Rev. A: 10/15/01