2-6 SETTING THE HIGH PRESSURE RELIEF VALVE (See Fig. 2-1)
When new, the high pressure relief valve is set at the maximum setting at 4,000 to 4,200 psi for normal use. The high
pressure relief valve may be set for relief at any pressure between 2,300 psi to 4,200 psi as required. The following
procedure may be used to set and verify the relief valve's performance and setting.
Do not set the high pressure relief valve for less than 2,300 psi since fully charged nitrogen tanks
may be pressurized to that level.
Setup the cart per paragraph 2-5.
Open both nitrogen tank valves and pump drive valve, V1.
Adjust low pressure regulator, R1, T-handle clockwise slowly until the booster pump cycles and the pump outlet
pressure gauge, G3, reads 4000 psi.
Loosen the locknut on the knob of the high pressure relief valve, SV2, and turn the knob counterclockwise.
Relief valve, SV2, will exhaust. Continue turning the knob counterclockwise until the pump outlet pressure
gauge, G3, reads at the desired setting. Tighten locknut to secure the knob position.
Turn the low pressure regulator, R1, T-handle fully counterclockwise until regulated low pressure gauge, G2,
Depressurize and shut down the system per paragraph 2-7.
2-7. SHUTDOWN PROCEDURE (See Fig. 2-1)
To depressurize the High Pressure Nitrogen Servicing Cart and shutdown the system, perform the following steps:
Close the valves on the nitrogen tanks.
If the regulated high pressure gauge, G4, reads zero psi, rotate the high pressure regulator, R2, T-handle
clockwise until G4 reads 300 psi minimum. If high pressure gauge, G4, already reads pressure above 300 psi,
do not adjust the regulator.
Open the high pressure vent valve, V2, to bleed off the high pressure. When pressure is bled off, do not turn
high pressure regulator, R2, handle at this time.
Turn low pressure regulator, R1, handle clockwise until handle is free spinning. The regulated low pressure
gauge, G2, will still show some pressure. Open pump drive valve, V1, to exhaust this pressure through the
booster pump exhaust.
The system is depressurized. Turn the valves V1, V2 and V3 clockwise to shut off valves and turn the high
pressure regulator, R2, T-handle counterclockwise until handle is free spinning. The shop air regulator, R3, may
be left set where it is.
If the nitrogen tanks are to be removed, unbuckle the upper and lower tank retention straps of the tank to be
removed. Carefully pull the tank out of its saddle and roll the tank away from the cart. Repeat with the second
tank if used.