Electronics International FL-2 - 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 resis-
tance 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