PS Magazine - TB 43-PS-684
PS, The Preventative Maintenance Monthly
ISSUE 684
NOVEMBER 2009
12
PS 684
NOV 09
Follow these additional troubleshooting instructions.
Wear the proper personal protective equipment (PPE), such as gloves and
eye protection, and inspect the V19 for the following:
A.
The INPUT plastic fuel line should be installed on the left (driver) side
of the V19. This line comes from the fitting located below the V12 (the
precheck valve) and gets pressure directly from the recirculation/bottom
loading port where you connect the D-1 nozzle.
B.
The plastic line to the pilot valve (in the bottom of the fuel tank just
above the V10) should be installed on the top right (passenger) side of the
V19 jet sensor box.
C.
The plastic line from the V12 (the precheck valve) should also be installed
on the bottom right (passenger side) of the V19.
D.
Inspect the brass elbows that connect all three lines to the V19. If you
can move them at all, they are too loose. So remove, clean and reinstall
them securely using thread seal tape on the threads going into the V19.
Do not put tape on the threads that go into the brass nut end where the
plastic fuel lines attach. Tape in the wrong place could add debris to the
line, and is not needed for the fitting-to-tube connection.
Inspect the direct line from the fuel inlet to the left side of the V19 for
damage or blockage.
E. Connect the tanker, set up to bottom load, to a clean fuel source
(possibly another M978 tanker). Follow TM 9-2320-279-10-1.
F.
Stop bottom loading/recirculating. Close the connected D-1 nozzle and
let the pressure bleed off for three minutes. Then open the manhole cover.
Remember to wear your PPE!
Following these steps ought to get the truck bottom loading or
recirculating properly.
If the truck still will not take fuel by bottom loading or recirculation, check
the line going to the pilot valve to see if it is loose or cracked, as shown in
the HEMTT troubleshooting. The only possible remaining fault is a bad pilot
valve or a bad V10.
Checking or repairing either involves entering the tank itself, so confined
space and fuel vapor issues are involved. Before troubleshooting or repairing
inside the tank, get guidance from your unit safety officer. You’ll need to
know the safety requirements for working inside of a fuel tank. And you may
need to be certified to work inside the tank.
Continual Screeching?
Note that sometimes your HEMTT tanker’s V19 system will receive enough
fuel pressure to open, but not to open completely. This problem can be
identified by a
continual
screeching noise coming from the V10 as it opens
and closes continually while recirculating or bottom loading.
I have found this problem to be more likely when bottom loading at a fuel
dispensing pump station that loads fuel at 300 gpm. If you hear continual
screeching coming from the V10 valve when bottom loading, there could be a
pressure problem with the V-19 jet level sensor.
Also, note that all V10 valves give a few screeches when they first open
while loading fuel at high volumes. They could screech again when they
close because the tank is full, or because the operator is testing the V12
precheck valve.
All of our tankers work fine now that we’ve cleaned out debris from the
V12/V19 system and jet level sensor, and repaired some trucks with loose
brass elbows received from the RESET program.
SSG Paul McFarland
B Co 2-135th GSAB
Lincoln, NE
Forward driver side
(roadside)
Passenger side
(curbside)
From B/L rec
below V-12
To pilot valve
in tank (V-14)
From V-12 pre
check valve
thanks
for the
detailed
trouble-
shooting
tips,
sergeant
mcfarland.
hemtt users should find
this information useful.
by the way, if your unit has newly
reset HEMTT -a2 tankers that don’t
recirculate or bottom load, use
any existing warranty and submit a
quality deficiency report (qdr).
A properly installed V19
looks like this
684.12-13.indd
1-2
9/16/09
9:11:28 PM
SSG P.M.
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