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Fuel
3. Inspect all connectors and wiring for signs of
loose connections, damage, or chafing.
4. Turn the ignition switch to the ON position and
check for fuel gauge response.
5. Repair or replace any damaged fuel gauge
components.
Vaporizer Inspecting
See
Fig. 6
for plumbing component locations.
1. Ensure that the vaporizer is secured to its
mounting brackets and that the mounting
brackets are secured to the frame. Inspect for
any signs of looseness.
2. Inspect the vaporizer fuel inlet and outlet lines for
signs of chafing, damage, or leaks.
3. Inspect the vaporizer coolant hoses for signs of
chafing, damage, or leaks.
4. Inspect all fittings for leaks.
5. Inspect the fuel shutoff solenoid valve for signs
of leaks or damage. Inspect the solenoid mount-
ing bracket for looseness.
6. Inspect the overpressure regulator for signs of
leaks or damage.
6.1
Ensure that the regulator is mounted se-
curely.
6.2
Check the overpressure regulator fittings
for signs of leaks or damage.
6.3
Ensure that the adjustment handle locking
nut (at the bottom of the overpressure
regulator) is tightened securely.
6.4
Inspect the pressure gauge for damage.
Ensure that the gauge sight glass is clear
and legible.
7. Repair or replace any leaking or damaged vapor-
izer components.
Pressure Increase Over Eight-
Hour Period
Less than 20 psi (138 kPa)
20 to 50 psi (138 to 345 kPa)
Cascadia Maintenance Manual, August 2015
Vacuum Integrity Test Results
None – Tank is normal
Monitor tank and test vacuum integrity again at next maintenance date
47–05 LNG Vacuum Integrity
Testing
WARNING
Natural gas is highly flammable. See the safety
precautions listed in Group 47 of the Cascadia
Workshop Manual. Failure to observe these pre-
cautions could lead to the ignition of the natural
gas, which could cause serious bodily injury or
death.
1. Ensure the fuel tank is between 50 and 75 per-
cent full.
2. Check the fuel tank pressure gauge (
Item 8) to ensure that pressure is within the nor-
mal range of 120 to 150 psi (827 to 1034 kPa).
3. Inspect the fuel tank for signs of frost spots or
outer surface sweating. Frosting or condensation
on the outer surface of the fuel tank may indicate
a loss of vacuum.
4. Check for a large variance in temperatures be-
tween the fuel tank and the fuel tank shroud. A
large variance in temperatures between the fuel
tank and the shroud may indicate a loss of
vacuum.
5. Operate the vehicle for ten minutes. Shut down
the engine, apply the parking brakes, and note
the time.
6. Wait fifteen minutes after shutting down the en-
gine, then record the fuel tank pressure and note
the time.
7. Allow the vehicle to stand for at least eight
hours, then record the fuel tank pressure again.
8. Use
Table 1
to determine whether the pressure
increase is within an acceptable range.
Remedy
47
Fig.
6,
47/7
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