S149-01-880 Issue F
Page 32
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Maintenance
5.11
Fault finding
A list of fault conditions and possible causes is provided in
Table 8
. If unable to rectify the fault using the table, call
your nearest Edwards Service Center for help.
Table 8 - Fault finding guide
Symptom
Probable Cause
Recommended Solution
Unsatisfactory Vacuum at Pump Inlet Contaminated or insufficient oil.
Check oil level; utilize gas ballast.
Drain and wipe out reservoir and
valve chamber. Refill with proper oil.
Solenoid oil valve not operating
properly or inoperative.
Check and if necessary, clean and/or
replace solenoid valve or coil.
Intake flange or cover bolts are
loose.
Tighten flange and side cover bolts
at regular intervals.
Oil manifold or integral oil
distribution leaking.
Tighten plugs and manifold screws.
Oil level sight glass leaking.
Carefully tighten screws.
Exhaust valve not sealing.
Disassemble, clean and check all
parts thoroughly.
Replace any damaged or worn parts.
Pump seizes or knocks excessively;
internal parts severely worn or
broken.
Disassemble piston assembly.
Replace broken or worn parts.
Leakage in vacuum system.
Check system as described in
Section 4
.
Excessive Pump Noise
Pump knocking abnormally.
Knocking is normal at blank-off.
Excessive Pump Noise
Check oil level and oil solenoid valve
for proper operation.
Broken parts or foreign material in
the pump.
Disassemble and remove foreign
material in the pump.
Replace broken parts as required.
Pump seizure resulting from
insufficient lubrication or presence
of foreign material.
Check solenoid valve for proper
operation.
Disassemble and remove foreign
material. Ensure oil lines are not
clogged.
Smooth minor scoring with #500
emery cloth and wash thoroughly
then oil before installing. Note: a
certain amount of scoring to the
piston, cylinder and other parts
usually will not seriously affect the
vacuum obtainable so long as scoring
is not in a continuous gouge around
the circumference of the piston
surface.
