Greenlee WW 980 Manuel D'instructions page 15

Troubleshooting—Pilot-Operated Valve (cont'd)
Pilot-operated valve will
not close. (cont'd)
Greenlee Tools, Inc.
The ball seat of the low-pressure
bypass check valve is damaged.
Low-pressure bypass check ball
seat is oversized.
A particle of dirt or some other
foreign object is holding the low-
pressure relief valve open.
Low-pressure relief valve is set
too low.
Low-pressure bypass check ball
seat is damaged.
Low-pressure bypass check seat
is oversized.
The pilot piston does not advance
freely.
Valve seat is damaged.
980 Hydraulic Power Pump
See Ball Seat Refinishing, Figure B2, B3 and B4 in
the Repairs section of this manual.
Replace the pump block (84).
Disassemble, clean and inspect the valve piston
(48), spring (47), ball (46), spring (45) and stem
(44). Replace parts as necessary.
See Low-Pressure Relief Setting, Figure A4 in the
Repairs section of this manual.
See Ball Seat Refinishing in the Repairs section of
this manual. Figures B2, B3, and B4.
Replace the pump block (84).
See Hydraulic Schematic (7).
See Low-Pressure Relief Setting, Figure A4 in the
Repairs section of this manual. Clean and inspect
items 42-49. Replace parts as necessary.
See Hydraulic Schematic (3, 7).
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