NMC-WOLLARD MB-4 200-DF, Operation, Maintenance And Parts Manual

Page: 59 / 321

The use of a pressure regulator on the com-
mercially available nitrogen bottle to regulate
pressure to the charging and gauging unit is
highly recommended.
NOTE: Full nitrogen pressure may damage
the gauge.
Connect the charging hose to a commer-
cially available nitrogen bottle by means of
the G4 adapter (other adapters are avail-
able, check with factory for type); the
adapter connects to the cap screw “G1 “.
Connect cap nut “M” of the charging hose to
check valve “C” of the charging and gauging
unit (see fig. 5). Connect the appropriate
charging and gauging unit to the accumula-
tor by following the instructions previously
described.
Initial Charging
When charging an accumulator that has no
initial gas precharge, allow 20 to 30 minutes
for the gas temperature and thus pressure to
stabilize. Recheck the gas precharge pres-
sure and adjust if necessary.
Turn T-handle 3 full turns to open. Proceed
to “Filling”.
Pressure Increase
When charging an accumulator that has an
existing gas precharge, allow 5 to 10 min-
utes for the gas temperature and thus pres-
sure to stabilize.
FPS Unit
Turn T-handle “A” clockwise until the gauge
needle begins to deflect, then turn it another
full turn.
Filling
Open the shut-off valve on the commercially
available nitrogen bottle and slowly fill the
accumulator with dry nitrogen gas.
Precharge very slowly until the pressure in
the accumulator reaches 100 psi. Once
100 psi is reached, the charging rate can
increase. Charging too quickly may dam-
age the accumulator.
NOTE : The gauge registers the line pres-
sure, not necessarily the accumulator
pressure while charging.
After allowing the appropriate time for the
gas temperature and thus pressure to sta-
bilize, adjust the gas precharge pressure
as required, refer to “Pressure Increase” or
“Pressure Release”.
Once the desired gas precharge pressure
is reached close the shutoff valve on the
commercially available nitrogen bottle. Re-
move the charging and gauging unit from
the gas valve as described under “Re-
moval of Charging and Gauging Unit”, fol-
lowing.
Removal Of Charging And Gauging Unit
Close the shut-oft valve on the commer-
cially available nitrogen bottle before re-
moving the charging and gauging unit.
FPS Unit
Turn T-handle “A” counter clockwise until
resistance is felt to close the gas valve.
Open manual bleed valve “B” to relieve
pressure in the charging and gauging unit.
Proceed to “Disconnecting”.
Disconnecting
Unscrew the charging and gauging unit
from the gas valve. Check for leaks. None
are permissable
Completion
PREVENTIVE MAINTENANCE PAGE 3-13
JULY 31, 2007
M200 MB4 Tow Tractor Manual No. 42975