REFLECTOR:Sump Tank Low Level Light Problems

Scott Baker reflector@tvbf.org
Mon, 14 Jul 2003 18:59:58 -0400


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If it's not too much of a problem, I suggest that you remove the float =
switch and inspect it for proper function.  The hollow bulb may be =
filled (or partially filled) with fuel.  Some of the older float =
switches were design for designed to float in water and not necessarily =
in fuel.  The specific gravity of fuel is, of course, less than water =
(water sinks in fuel) ... and with that in mind, the float while working =
great in water, is not quite a buoyant in fuel ... which means that any =
collection (even a little bit) of fuel in the bowl - or - maybe the flow =
disturbance of fresh fuel entering into the sump tank, might cause the =
floaty thing to "bob it's head" down and give you an indication of Low =
Fuel.  When you test the float, dunk it in fuel (rather than water) to =
see if it has a strong "float" action.  If not, I suggest replacing the =
float switch with a new unit.
Best regards,
Scott B.

By the way, the factory XL prototype N97XL had a similar problem (the =
"low fuel" light coming on in flight).  Scared the bejesus out of you =
when the light came on ... solution was to kick a rudder to force the =
fuel in the sump tank to "slosh" and the light would blink "out".  Oh =
well.

  ----- Original Message -----=20
  From: Ralph Pierce=20
  To: reflector@tvbf.org=20
  Sent: Monday, July 07, 2003 11:03 AM
  Subject: REFLECTOR:Sump Tank Low Level Light Problems


  I have been trying to get in the air for the past several weeks, but =
keep getting a low level light on my sump tank.  I have checked the =
wiring, and blew our my vent line from the sump tank to no avail.
  I taxi out and during the runup checks, the light will come on.  So I =
taxi back to the hanger - and the only way I can get the light to go out =
is to hit the sump tank good and hard.  I have gas in both wings and =
they seem to be feeding evenly.
      Has anybody experienced a similar problem?

                                              Ralph
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<META http-equiv=3DContent-Type content=3D"text/html; =
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<META content=3D"MSHTML 6.00.2800.1106" name=3DGENERATOR>
<STYLE></STYLE>
</HEAD>
<BODY bgColor=3D#ffffff>
<DIV><FONT face=3DArial size=3D2>If it's not too much of a problem, I =
suggest that=20
you remove the float switch and inspect it for proper function.&nbsp; =
The hollow=20
bulb may be filled (or partially filled) with fuel.&nbsp; Some of the =
older=20
float switches were design for designed to float in water and not =
necessarily in=20
fuel.&nbsp; The specific gravity of fuel is, of course, less than water =
(water=20
sinks in fuel) ... and with that in mind, the float while working great =
in=20
water, is not quite a buoyant in fuel ... which means that any =
collection (even=20
a little bit) of fuel in the bowl - or - maybe the flow disturbance of =
fresh=20
fuel entering into the sump tank, might cause the floaty thing to "bob =
it's=20
head" down and give you an indication of Low Fuel.&nbsp; When you test =
the=20
float, dunk it in fuel (rather than water) to see if it has a strong =
"float"=20
action.&nbsp; If not, I suggest replacing the float switch with a new=20
unit.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>Best regards,</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>Scott B.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT>&nbsp;</DIV>
<DIV><FONT face=3DArial size=3D2>By the way, the factory XL prototype =
N97XL had a=20
similar problem (the "low fuel" light coming on in flight).&nbsp; Scared =
the=20
bejesus out of you when the light came on ... solution was to kick a =
rudder to=20
force the fuel in the sump tank to "slosh" and the light would blink=20
"out".&nbsp; Oh well.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT>&nbsp;</DIV>
<BLOCKQUOTE dir=3Dltr=20
style=3D"PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; =
BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px">
  <DIV style=3D"FONT: 10pt arial">----- Original Message ----- </DIV>
  <DIV=20
  style=3D"BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: =
black"><B>From:</B>=20
  <A title=3Dpierce2@cableone.net =
href=3D"mailto:pierce2@cableone.net">Ralph=20
  Pierce</A> </DIV>
  <DIV style=3D"FONT: 10pt arial"><B>To:</B> <A =
title=3Dreflector@tvbf.org=20
  href=3D"mailto:reflector@tvbf.org">reflector@tvbf.org</A> </DIV>
  <DIV style=3D"FONT: 10pt arial"><B>Sent:</B> Monday, July 07, 2003 =
11:03=20
AM</DIV>
  <DIV style=3D"FONT: 10pt arial"><B>Subject:</B> REFLECTOR:Sump Tank =
Low Level=20
  Light Problems</DIV>
  <DIV><BR></DIV>
  <DIV><FONT face=3DArial size=3D2>I have been trying to get in the air =
for the past=20
  several weeks, but keep getting a low level light on my sump =
tank.&nbsp; I=20
  have checked the wiring, and blew our my vent line from the sump tank =
to no=20
  avail.</FONT></DIV>
  <DIV><FONT face=3DArial size=3D2>I taxi out and during the runup =
checks, the light=20
  will come on.&nbsp; So I taxi back to the hanger - and the only way I =
can get=20
  the light to go out is to hit the sump tank good and hard.&nbsp; I =
have gas in=20
  both wings and they seem to be feeding evenly.</FONT></DIV>
  <DIV><FONT face=3DArial size=3D2>&nbsp;&nbsp;&nbsp; Has anybody =
experienced a=20
  similar problem?</FONT></DIV>
  <DIV><FONT face=3DArial size=3D2></FONT>&nbsp;</DIV>
  <DIV><FONT face=3DArial size=3D2>&nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; =

  &nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; =
&nbsp;&nbsp;&nbsp;=20
  &nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; =
&nbsp;&nbsp;&nbsp;=20
  &nbsp;&nbsp;&nbsp; Ralph</FONT></DIV></BLOCKQUOTE></BODY></HTML>

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