DOC AIRBUS | AMM A320FRESERVOIR PRESSURIZATION INDICATING - DESCRIPTION AND OPERATION
** ON A/C NOT FOR ALL
** ON A/C NOT FOR ALL
1. General
The reservoir pressurization indicating system monitors the internal pressure of the hydraulic reservoirs. If the pressure in one or more of the reservoirs is too low, the indicating system gives signals. These signals give warnings during flight (for immediate action) and after flight (for maintenance action).
** ON A/C NOT FOR ALL The reservoir pressurization indicating system monitors the internal pressure of the hydraulic reservoirs. If the pressure in one or more of the reservoirs is too low, the indicating system gives signals. These signals give warnings during flight (for immediate action) and after flight (for maintenance action).
2. Component Location
** ON A/C NOT FOR ALL 
Component Location| FIN | FUNCTIONAL DESIGNATION | PANEL | ZONE | ACCESS DOOR | ATA REF |
|---|---|---|---|---|---|
| ** ON A/C ALL | |||||
| 1384GH | AIR PRESSURE SWITCH | 148 | 29-34-11 | ||
| 2384GH | AIR PRESSURE SWITCH | 197FB | 197 | 29-34-11 | |
| 3384GH | AIR PRESSURE SWITCH | 196BB | 196 | 29-34-11 | |
| ** ON A/C NOT FOR ALL | |||||
| 2385GH | TRANSMITTER AIR PRESS | 197FB | 197 | 29-34-12 | |
3. System Description
The reservoir pressurization indicating system has three pressure switches. One pressure switch is installed on the reservoir of each hydraulic system and is connected directly to its air space.
Each pressure switch (1384GH), (2384GH) and (3384GH) sends a discrete signal if the pressure in the related reservoir is too low. The signal goes to the two system data acquisition concentrators (SDAC) for electronic centralized aircraft monitor (ECAM) warnings. The signal also goes to the overhead panel for FAULT light operation.
** ON A/C NOT FOR ALL The reservoir pressurization indicating system has three pressure switches. One pressure switch is installed on the reservoir of each hydraulic system and is connected directly to its air space.
Each pressure switch (1384GH), (2384GH) and (3384GH) sends a discrete signal if the pressure in the related reservoir is too low. The signal goes to the two system data acquisition concentrators (SDAC) for electronic centralized aircraft monitor (ECAM) warnings. The signal also goes to the overhead panel for FAULT light operation.
A. Reservoir Air Pressure-Switches FIN: 1384-GH FIN: 2384-GH FIN: 3384-GH
The three reservoir air pressure-switches are the same and they are interchangeable. The switches are cylindrical with a steel body. The body holds a microswitch assembly. At one end of the body is the electrical connector. The other end of the body has a thread to connect it to the reservoir. It is also the pressure inlet. A bonding tag is attached to the body.
The contacts of the pressure switch close when the pressure decreases to
2.5 +/- 0.1 bar absolute (37 +/- 1.45 psia) (1.5 +/- 0.1 bar relative (22 +/- 1.45 psig)). The contacts open when the pressure increases to 2.7 bar absolute (40 psia) (1.7 bar relative (25 psig)).
The three reservoir air pressure-switches are the same and they are interchangeable. The switches are cylindrical with a steel body. The body holds a microswitch assembly. At one end of the body is the electrical connector. The other end of the body has a thread to connect it to the reservoir. It is also the pressure inlet. A bonding tag is attached to the body.
The contacts of the pressure switch close when the pressure decreases to
2.5 +/- 0.1 bar absolute (37 +/- 1.45 psia) (1.5 +/- 0.1 bar relative (22 +/- 1.45 psig)). The contacts open when the pressure increases to 2.7 bar absolute (40 psia) (1.7 bar relative (25 psig)).
5. Operation
A. ECAM (Flight) Warnings
The pressure switches (1384GH), (2384GH) and (3384GH) monitor the air pressure in each reservoir. Usually the reservoirs are pressurized to 3.5 bar relative (50 psig) (4.5 bar absolute (65 psia)). If the pressure decreases to less than 2.5 +/- 0.1 bar absolute (37 +/- 1.45 psia) (1.5 +/- 0.1 bar relative (22 +/- 1.45 psig)), the contacts of the pressure switch close. A discrete signal is sent to the two SDAC which causes the ECAM system to show the applicable warnings. A discrete signal which causes the applicable FAULT lights to come on, is also sent to the overhead panel.
The following warnings occur:
When the air pressure in the reservoir increases to more than 2.7 bar absolute (39 psia) (1.7 bar relative (25 psig)), the contacts of the pressure switch open and the warnings are cancelled.
The pressure switches (1384GH), (2384GH) and (3384GH) monitor the air pressure in each reservoir. Usually the reservoirs are pressurized to 3.5 bar relative (50 psig) (4.5 bar absolute (65 psia)). If the pressure decreases to less than 2.5 +/- 0.1 bar absolute (37 +/- 1.45 psia) (1.5 +/- 0.1 bar relative (22 +/- 1.45 psig)), the contacts of the pressure switch close. A discrete signal is sent to the two SDAC which causes the ECAM system to show the applicable warnings. A discrete signal which causes the applicable FAULT lights to come on, is also sent to the overhead panel.
The following warnings occur:
- the single-chime audio warning operates,
- the MASTER CAUT lights on the glareshield come on,
- the applicable FAULT lights on the overhead panel come on,
- the applicable warnings appear on the system and engine/warning displays (lower DU and upper DU) of the ECAM.
When the air pressure in the reservoir increases to more than 2.7 bar absolute (39 psia) (1.7 bar relative (25 psig)), the contacts of the pressure switch open and the warnings are cancelled.