Pilot-Operated Valve - Greenlee WW 980 Manuel D'instructions

Troubleshooting—Pilot-Operated Valve
Pilot-operated valve will
not open. Pilot-operated
valve will not open fully.

Pilot-operated valve

opens too slowly.
Pilot-operated valve will
not close.
Greenlee Tools, Inc.
The pilot piston does not return
freely.
Wrong oil viscosity.
Oil is dirty.
Oil is cold.
Pilot piston components may be
worn or damaged.
Low-pressure bypass check valve
is set incorrectly.
The ball seat of the low-pressure
bypass check valve is damaged.
A particle of dirt or some other
foreign object is holding the low-
pressure bypass check valve open.
Low-pressure bypass check valve
is faulty.
980 Hydraulic Power Pump
See Hydraulic Schematic (7) and refer to Low-
Pressure Relief Setting, Figure A4 in the Repairs
section of this manual.
Replace oil with the type recommended in the
Specifications section of this manual.
Replace oil with the type recommended in the
Specifications section of this manual.
Preheat oil. Without an accessory connected to
the coupler, run the pump to build pressure, then
release. Repeat until oil is warm.
Clean and inspect items 42-49. Replace parts as
necessary.
See Hydraulic Schematic (4).
If set too low: The pump cannot shift to the high-
pressure stage. See Pressure Adjustment for the
Low-Pressure Bypass Check, Figure A5 in the
Repairs section of this manual.
If set too high: The pump cannot restart under
pressure. See Pressure Adjustment for the Low-
Pressure Bypass Check, Figure A5 in the Repairs
section of this manual.
See Ball Seat Refinishing, Figure B2 in the Repairs
section of this manual.
Disassemble, clean and inspect spring (70) and
9/32" ball (71). Replace parts as necessary.
See Hydraulic Schematic (4).
If set too low: The pump cannot shift to the high-
pressure stage. See Pressure Adjustment for the
Low-Pressure Bypass Check, Figure A5 in the
Repairs section of this manual.
If set too high: The pump cannot restart under
pressure. See Pressure Adjustment for the Low-
Pressure Bypass Check, Figure A5 in the Repairs
section of this manual.
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