APU FUEL PUMP SYSTEM - FAULT ISOLATION PROCEDURES
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 TASK 28-22-00-810-801
 APU Fuel System - Low Pressure
 1. Possible Causes
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 - VALVE-AIR RELEASE, L WING TK (86QM)

 - PRESS SWITCH-APU FUEL PRESSURE (7QC)

 - PUMP-APU FUEL (4QC)

 - SWITCH-APU FUEL LP (5030QM)

 - RELAY 6QC

 - RELAY 5QC

 - wiring

 - RELAY 9QC

 - RELAY 4KD R - RELAY 78KD
 2. Job Set-up Information
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 A. Referenced Information
 -------------------------------------------------------------------------------REFERENCE DESIGNATION -------------------------------------------------------------------------------
AMM 28-21-41-000-001 Removal of the Low Pressure (LP) Air-Release-Valve 86QM(87QM) AMM 28-21-41-400-001 Installation of the Low Pressure (LP)
 Air-Release-Valve 86QM(87QM) AMM 28-22-14-000-001 Removal of the APU Fuel LP-Switch 5030QM AMM 28-22-14-400-001 Installation of the APU Fuel LP-Switch 5030QM AMM 28-22-15-000-001 Removal of the APU Fuel Pressure Switch (7QC) AMM 28-22-15-400-001 Installation of the APU Fuel Pressure Switch (7QC) AMM 28-22-51-000-001 Removal of the APU Fuel Pump (4QC) AMM 28-22-51-400-001 Installation of the APU Fuel Pump (4QC) AMM 49-31-00-710-001 Operational Test of the APU Fuel Low Pressure Circuit
 (GTCP 36-300) AMM 49-31-00-710-002 Operational Test of the APU Fuel Low Pressure Circuit
 (APS 3200)
 ASM 28-22/01
 ASM 28-29/01
 ASM 49-61/02

 「一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一1 EFF : ALL ∞∞28-22-00∞∞∞∞∞∞∞∞∞∞Page 201
 Aug 01/05 CES

 3. Fault Confirmation
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 **ON A/C 001-049, 051-099, 101-105, 151-199, 201-210,
 A. Do the operational test of the APU fuel low pressure circuit (Ref. AMM TASK 49-31-00-710-001).
 NOTE : Make sure that the subsequent system is serviceable before you
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 start the fault isolation procedure:

 - the main fuel pump system (Ref. 28-21-00),

 - the APU LP fuel shutoff system (Ref. 28-29-00).

R **ON A/C 106-149, 211-299, 301-399, 401-499,
 A. Do the operational test of the APU fuel low pressure circuit (Ref. AMM TASK 49-31-00-710-002).
 NOTE : Make sure that the subsequent system is serviceable before you
____
 start the fault isolation procedure:

 - the main fuel pump system (Ref. 28-21-00),

 - the APU LP fuel shutoff system (Ref. 28-29-00).

 **ON A/C ALL
 4. Fault Isolation
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 A. If the test gives the subsequent results: - on the lower ECAM display unit, the FUEL LO PR advisory is off with the L main fuel pump in operation,
 - on the lower ECAM display unit, the FUEL LO PR advisory comes on with the APU fuel pump in operation.
 (1) replace the VALVE-AIR RELEASE, L WING TK (86QM) (Ref. AMM TASK 28-21-41-000-001) and (Ref. AMM TASK 28-21-41-400-001).
 B. If the test gives the subsequent results: .on the lower ECAM display unit, the FUEL LO PR advisory is off with the L main fuel pump in operation, .on the lower ECAM display unit, the FUEL LO PR advisory comes on and the APU fuel pump does not operate:
 - push the FUEL LINE pushbutton switch 8QC to operate the APU FUEL PUMP 4QC.
 (1) If the APU FUEL PUMP 4QC operates:
 - replace the PRESS SWITCH-APU FUEL PRESSURE (7QC) (Ref. AMM TASK 28-22-15-000-001) and (Ref. AMM TASK 28-22-15-400-001).
 (a) If the fault continues:
 - do a check of the RELAY 6QC and replace if necessary.
 「一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一一1 EFF : ALL ∞∞28-22-00∞∞∞∞∞∞∞∞∞∞Page 202
 Aug 01/05 CES

 (b) If the fault continues:

 - do a check of the RELAY 5QC and replace if necessary.

 (c) If the fault continues:

 - do a check and repair the wiring from the: CB 2QC to the RELAY 6QC A/B2, RELAY 6QC A/C3 to the PRESS SWITCH 7QC A/B, RELAY 5QC A/X1 to the PRESS SWITCH 7QC A/A, RELAY 5QC A/X2 to the GND (Ref. ASM 28-22/01).
 (2) If the APU FUEL PUMP 4QC does not operate:
　
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