Appendix A
Air Purge Screw Operation
A-4
Air Purge Screw Operation
The air purge screw is used to rid air from the line and manifold hydraulic cavities after opening a port in the
manifold (e.g., after installing a line leak detector). When repairs to the pump have been made, the technician will
need to purge the air within the manifold as shown in diagram 1 of Figure A-6. The air purge screw is rotated 2-3
turns counterclockwise, then the pump is turned on.
CAUTION! The air purge screw is retained by the hitch pin to limit travel. Do not attempt to rotate beyond 3 turns.
As the pump runs, any air in the cavities is pushed through the small tank return port as shown in diagram 2. After
the pump has run for about 2 -3 minutes the air will have been removed from the manifold and piping as shown in
diagram 3. While the pump is still running, turn the air purge screw clockwise until it is completely closed. Open
the ball valve down line from the pump.
Figure A-6. Purging air from manifold
To tank
Pump on
Pump on 2-3 min.
To tank
AIR
AIR
1
2
3