PIPER AIRCRAFT, INC.
PA-28-161, WARRIOR III
MAINTENANCE MANUAL
PAGE 5
Nov 30/06
3J1
37-10-00
4. Auxiliar
y
Vacuum Pump (Optional) (Refer to Figures 2 and 3.)
The auxiliary vacuum pump installation has a 24 Vdc pump motor and relay. The VAC OFF AUX ON
switch is located on the extreme left instrument panel on the Warrior III.
CA
UTION: REPLACE AUXILIARY VACUUM PUMP/MOTOR ASSEMBLY WITH A NEW, WORKING
UNIT, OR SEND UNIT TO VENDOR FOR REPAIR. FOR PROPER OPERATION, IT IS
IMPORTANT THAT THE PUMP/MOTOR ASSEMBLY BE REPAIRED BY TRAINED
PERSONNEL.
The auxiliary vacuum pump mounted, on the firewall, is a backup source to operate the gyro flight
instruments if the engine driven pump fails. A 20 amp circuit breaker in the system protects the pump
motor circuit. A 5 amp circuit breaker protects the annunciator light switch.
A. Operational Check, Engine Off
CA
UTION: VERIFY ALL ELECTRICAL EQUIPMENT IS OFF BEFORE BEGINNING ENGINE
OFF OPERATIONAL CHECK.
CA
UTION: RUN AUXILIARY PUMP FOR ONLY A SHORT PERIOD OF TIME. EXCESSIVE TIME
OF OPERATION WEAKENS BATTERY TO AN UNRELIABLE CHARGE LEVEL.
(1) Select battery master switch on. Check that VAC OFF annunciator illuminates.
(2) Press VAC OFF/AUX ON annunciator switch. Check that AUX ON annunciator lights, and VAC
OFF annunciator extinguishes. Check that the vacuum gauge reads between 4.8 and 5.2 in. hg.
(3) Press VAC OFF/AUX ON annunciator switch to cycle it to the off position. Check that AUX ON
annunciator goes out, and VAC OFF annunciator illuminates.
(4) Select battery master switch off.
B. Removal
WARNING: VERIFY BATTERY MASTER SWITCH IS OFF.
W
ARNING: COVER AUXILIARY VACUUM PUMP SWITCH ON THE INSTRUMENT PANEL WITH
AN INOP PLACARD, IF A REPLACEMENT AUXILIARY PUMP/MOTOR ASSEMBLY
IS NOT INSTALLED BEFORE NEXT FLIGHT.
CA
UTION: THE AUXILIARY VACUUM PUMP AND MOTOR COMPRISE A SEALED ASSEMBLY
AND MUST BE REMOVED AS ONE ASSEMBLY.
CA
UTION: THE ELAPSED TIME INDICATOR IS MATCHED TO THE PUMP/MOTOR ASSEMBLY
AND MUST BE REMOVED AND REPLACED WITH THE PUMP/MOTOR ASSEMBLY.
(1) Remove top engine cowling.
(2) Disconnect and mark hoses from pump/motor assembly.
(3) Disconnect and mark electrical leads at terminals on pump/motor assembly.
(4) Loosen band clamps and remove pump/motor assembly from airplane.
(5) Locate elapsed time indicator under instrument panel; disconnect and mark electrical leads.
CA
UTION: INSULATE AND SECURE LEADS REMAINING IN AIRPLANE IF A
REPLACEMENT ELAPSED TIME INDICATOR IS NOT INSTALLED
IMMEDIATELY.
(6) Remove elapsed time indicator.
(7) If auxiliary vacuum pump will not be installed immediately, place protective covers over open
end of vacuum lines, insulate all electrical leads relative to the auxiliary vacuum system, and
install top engine cowling.
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