6. Open the servicing valve of the system being
6. Relieve pressure in the charging station hose,
and slowly disconnect it from the recharge
charged.
valve. (The hose is disconnected slowly to allow
7. When charging is completed, close the servicing
any trapped gas to vent.) Replace the dust cover
valve on the system being charged.
on the recharge valve.
8. Rotate the bleed valve to the BLEED position to
Maintenance
expel nitrogen from the servicing hose.
9. Disconnect the servicing hose.
The portable high-pressure nitrogen cylinder, if
handled properly, requires very little attention other
10. Close the shutoff valve, and open the bleed
then scheduled maintenance. If the unit shows signs of
valve. The cylinder pressure gauge and the
malfunctioning, however, the trouble must be located
delivery pressure gauge should drop to about
and remedied. Table 9-1 lists some of the possible
zero.
troubles, their causes, and remedies.
11. Close the pressure regulator and bleed valve.
NOTE: The troubleshooting charts presented in
this training manual are only examples and are not
12. Cap and stow the servicing hose.
necessarily complete. Before attempting repairs on
RECHARGING THE NITROGEN CYLIN-
any item of equipment, consult the applicable
DER.--If cylinder pressure falls below what is
maintenance instruction manual. There you will find
required for the next charging job, the cylinder must be
complete, up-to-date instructions for maintaining the
recharged. If recharging is required, follow the
equipment.
procedures outlined below.
Safety
CAUTION
For safe operation of the portable, high-pressure,
Do not over pressurize the cylinder. It has a
walk-around bottle, strictly observe the following
working pressure of 3,000 psi and should only be
safety precautions:
recharged to this pressure.
Open all valves slowly.
Position the bottle so that the servicing hose is
not under tension while charging. Never stretch
1. Ensure the pressure regulator and bleed valve
the servicing hose to reach a connection.
are closed. Open the shutoff valve to determine
Never drag the servicing hose or pull the bottle
the amount of pressure in the cylinder, and then
close it to isolate the regulator.
by the servicing hose. Always coil the hose
neatly around the four frame hose brackets when
2. Remove the dust cover from the recharge valve,
not in use, and secure the chuck with the strap
and connect a nitrogen charging station hose to
assembly.
the recharge valve.
Never permit oil, grease or readily combustible
3. Open the recharge valve. This permits nitrogen
material to come into contact with the system
to flow into the cylinder.
components or fittings.
NOTE: The pressure regulator on the charging
Always keep the recharge valve capped to
station should be adjusted to 3,000 psi.
prevent entry of foreign matter into the system.
4. Open the servicing valve on the charging station
After a charging operation, always bleed the
until you sense that the flow of nitrogen into the
servicing hose before securing the regulator.
cylinder has stopped, and then close the
This prevents system pressure and contaminants
charging station servicing valve.
from backing up into the regulator chambers.
5. Open the cylinder shutoff valve and check the
Always keep the nitrogen recharging valve
pressure indicated on the cylinder pressure
safety-wired to the manifold.
gauge. When the cylinder pressure gauge reads
Abide by the color code of the cylinder. That is,
3,000 psi, close the recharge valve to stop the
flow of nitrogen to the cylinder.
NEVER recharge a cylinder coded for
9-5
