Troubleshooting, Warning – Hitachi SERIES J User Manual
Page 12

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Troubleshooting
WARNING
To reduce the risk of serious injury whenever you
are instructed to relieve pressure, always follow the
Pressure Relief Procedure on page 8.
Relieve the Pressure before you check or service any
system equipment.
WARNING
Never operate the pump with the warning plate
(20) or the identification plate (40) removed. These
plates protect your fingers from pinching or ampu-
tation by moving parts in the air motor.
NOTE: Check all other possible problems and solu-
tions before disassembling the pump.
Problem
Cause
Solution
Pump fails to operate
Low air supply pressure or restricted air
lines
Increase air supply; clear*
Closed valves
Open
Clogged fluid lines, hoses, valves, etc.
Clear*
Damaged air motor
Service air motor
Empty fluid supply container
Refill and reprime, or flush
Continuous air exhaust
Worn or damaged air motor gasket,
packing, seal, etc.
Service air motor
Erratic pump operation
Empty fluid supply container
Refill and reprime, or flush
Held open or worn intake valve or
piston packings
Clear; service
Pump operates, but output is low
on the up stroke
Held open or worn piston
or packings
Clear; service
Pump operates, but output is low
on the down stroke
Held open or worn intake valve
Clear; service
Pump operates, but output is low
on both strokes
Low air supply pressure or
restricted air lines
Increase air supply; clear*
Closed valves
Open
Empty fluid supply container
Refill and reprime, or flush
Clogged fluid lines, hoses, valves, etc.
Clear*
Packing nut too tight
Loosen
Loose packing nut or worn packings
Tighten; replace
*Follow the Pressure Relief Procedure on page 8. Disconnect the fluid hose. If the pump starts when the air is
turned on again, the hose or gun is clogged.