Piper Arrow IV Turbo Maintenance Manual page 467

CHART 3701. TROUBLESHOOTING (VACUUM SYSTEM) (cont.)
Trouble
Normal pressure indica-
tion but sluggish operation
of instruments.
High system pressure.
Regulator cannot be ad-
justed to produce correct
pressure.
Vacuum correct on ground
but will not maintain pres-
sure at altitude.
Vacuum correct but pilot
reports pressure erratic or
shows complete loss in
flight.
Pressure can only be main-
tained at full throttle on
ground.
PIPER AIRCRAFT
PA-28RT-201 / 201T
MAINTENANCE MANUAL
Cause
Faulty instrument.
Vacuum regulator in-
correctly adjusted.
Vacuum regulator sticking
or dirty screen.
Lines leaking.
Vacuum pump mal-
functioning.
Vacuum pump mal-
functioning.
Regulator sticky.
Regulator sticky.
Oil in pump due to leaky
engine seal or cleaning fluid
blown into pump while
cleaning engine.
Leak in system.
Worn pump.
Stuck regulator.
2H20
Remedy
Replace instrument.
Adjust regulator.
Clean and check operation
of regulator.
Check lines and fittings.
Replace pump.
Replace pump.
Clean regulator.
Clean regulator.
Replace pump.
Repair or replace lines.
Replace pump.
Clean or replace regulator.
37-00-02
Page 37-02
December 1, 1978