DOC AIRBUS | AMM A320FENGINE FUEL AND CONTROL - DESCRIPTION AND OPERATION
** ON A/C NOT FOR ALL
1. General
The APU fuel system meters and distributes the fuel it receives from the A/C fuel system (Ref. AMM D/O 28-22-00-00).
Incoming fuel is received by the fuel control unit (FCU) and pumped to the flow divider assy. From there it is ducted via the fuel manifolds to the fuel nozzles.
A separate fuel circuit is provided to hydraulically operate the IGV-actuator and the Surge Control Valve (SCV).
** ON A/C NOT FOR ALL The APU fuel system meters and distributes the fuel it receives from the A/C fuel system (Ref. AMM D/O 28-22-00-00).
Incoming fuel is received by the fuel control unit (FCU) and pumped to the flow divider assy. From there it is ducted via the fuel manifolds to the fuel nozzles.
A separate fuel circuit is provided to hydraulically operate the IGV-actuator and the Surge Control Valve (SCV).
2. Component Location
** ON A/C NOT FOR ALL 
APU Fuel System - Component Location| ------------------------------------------------------------------------------- |
| FIN | FUNCTIONAL DESIGNATION | PANEL|ZONE|ACCESS | ATA |
| | | | | DOOR | REF. |
| ------------------------------------------------------------------------------- |
| 4005KM2 FUEL CONTROL UNIT (FCU) 315 315AL 49-32-11 |
| 4005KM1 FLOW - DIVIDER 315/ 315AL 49-32-12 |
| 8020KM MANIFOLD - PRIMARY FUEL 315/ 315AL/ 49-31-43 |
| 316 316AR |
| 8021KM MANIFOLD - SECONDARY FUEL 315/ 315AL/ 49-31-44 |
| 316 316AR |
3. System Description
A. Fuel Distribution (Ref. 49-31-00)
Incoming fuel from the A/C fuel system is received by the FCU. The FCU diverts some of the fuel into a hydraulic circuit to operate the IGV-actuator and the SCV. Returned fuel is routed back into the FCU.
The FCU also pressurizes and meters the fuel for APU operation. The fuel is passed through the flow divider assy to the primary and/or secondary fuel manifold. These deliver the fuel to the 10 dual-orifice fuel nozzles, located around the circumference of the combustion chamber. There the fuel is atomized.
Incoming fuel from the A/C fuel system is received by the FCU. The FCU diverts some of the fuel into a hydraulic circuit to operate the IGV-actuator and the SCV. Returned fuel is routed back into the FCU.
The FCU also pressurizes and meters the fuel for APU operation. The fuel is passed through the flow divider assy to the primary and/or secondary fuel manifold. These deliver the fuel to the 10 dual-orifice fuel nozzles, located around the circumference of the combustion chamber. There the fuel is atomized.
B. Fuel Control (Ref. 49-32-00)
The APU fuel control system operates fully automatically. During APU operation, the FCU, which is governed by the ECB, meters the fuel dependent on the APU load condition. The flow divider assy distributes the fuel via both fuel manifolds to the fuel nozzles. During APU start-up/shut-down, the FCU increases/reduces the quantity of fuel delivered to the flow divider assy. During APU start, the flow divider assy passes fuel to the combustion chamber via the primary fuel manifold only.
The APU fuel control system operates fully automatically. During APU operation, the FCU, which is governed by the ECB, meters the fuel dependent on the APU load condition. The flow divider assy distributes the fuel via both fuel manifolds to the fuel nozzles. During APU start-up/shut-down, the FCU increases/reduces the quantity of fuel delivered to the flow divider assy. During APU start, the flow divider assy passes fuel to the combustion chamber via the primary fuel manifold only.