It is also possible to pressurize the system with the electric pump when the engines are stopped. A P/B switch on the maintenance panel 50VU in the flight compartment stops the automatic function and starts the electric pump.
 The case drain fluid from the electric pump assembly goes to the LP circuit through a check valve 2041GM and a filter 2084GM. The seal drain fluid goes through a connection into the seal drain system (Ref. 29-17-00).
 A current transformer 2706GJ and a current unbalance detector 2707GJ together give protection if there is a fault in the electric pump motor. When a fault occurs, they stop the motor. A temperature switch is included in the motor. If the temperature of the motor is too high, the switch sends a signal to the ECAM and warning systems.
 The Ram Air Turbine (RAT) can also supply the Blue hydraulic system with HP fluid (Ref. 29-22-00). The RAT operates automatically when there is a total AC failure. It is also possible to operate the RAT from the flight compartment.
 On the ground, it is possible to pressurize the system from a ground supply. The system has self-sealing connections for a ground supply. They are installed on the ground service panel of the Blue hydraulic system.
 The ground service panel for the Blue hydraulic system is in the left-hand belly fairing, aft of the main landing-gear compartment. The components and connections which are necessary to service the Blue hydraulic system (not including the pressurization connection for the reservoir) are installed together in a group on it. The ground service panel has these components on it:
 -
the ground test suction and delivery connectors 2006GM and 2008GM,

 -
the depressurization valve 2087GM of the reservoir,

 -
the drain valve 2264GM of the reservoir,

 -
the RAT control panel.

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 **ON A/C 001-049, 051-058, 101-101,

 The system has a pulsation dampener 2092GM installed immediately downstream of the electric pump. It smoothes the output of the electric pump. Also installed downstream of the electric pump are a pressure switch 2074GJ and a check valve 2050GM. The pressure switch monitors the output pressure of the electric pump. The check valve stops the flow of fluid toward the electric pump if the system is pressurized from another source.
 The supply to all of the consumers goes through the HP manifold 2011GM. The supply to all of the consumers other than the slat motor and CSM/G also goes through the Leakage Measurement System (LMS) manifold.
 The HP manifold has ports which connect it to other parts of the system as follows:
 - a system pressure inlet from the pump, RAT and ground supply, - two outlets to the LMS manifold, - one outlet to the slat motor and CSM/G, - one outlet to the RAT, - one connection to/from the system accumulator 2070GM, - one outlet to the return (LP) circuit.
 A solenoid valve 2150GP on the HP manifold controls the flow of fluid to the
 LMS manifold. The solenoid valve is operated from the maintenance panel 50VU in the flight compartment. A HP filter 2048GM is installed on the system pressure inlet of the HP manifold. The filtration rating of the filter is 15 microns. 
R R R R  A pressure relief valve 2063GM installed on the HP manifold prevents too much pressure in the system. The pressure relief valve opens when the pressure increases to 237 bar (3436 psi). It closes when the pressure decreases to 220 bar (3190 psi).
R R R R  Two pressure switches 2151GN and 10CE-1 on the HP manifold monitor the pressure in the system. The pressure switch 2151GN sends data to the ECAM and warning systems. The pressure switch 10CE-1 sends data to the flight control system only. A pressure transmitter 2065GN transmits pressure data to the ECAM and warning system.
 The sampling valve 2187GM is installed on the HP manifold. It makes it possible to get samples of the system fluid for analysis. It is possible to take the sample with the system at full pressure.
 The priority valve 2064GM is also installed on the HP manifold. It stops the supply of fluid to non-essential consumers (slats and CSM/G) if the pressure in the system is too low. The priority valve closes (and stops the supply) 

R 1EFF : 001-049, 051-058, 101-101, 1 29-12-00Page 19 1 1 Aug 01/05 1 1 1CES 1 when the pressure decreases to 130 +0 -3 bar (1885 +10 -43 psi). The valve opens when the pressure increases to 140 +0 -5 bar (2030 +0 -72,5 psi).

 The check valves 2022GM, 2057GM and 2059GM are installed on the HP manifold to control the flow of fluid to and from the manifold.
 The system accumulator 2070GM has a direct connection to the HP manifold. The accumulator keeps the pressure in the system free from small changes. It also makes a supply of fluid available to replace any temporary shortage. This can happen if there is a sudden large demand and the pump has not had time to respond. The accumulator is pre-charged with nitrogen to 1885 psi (130 bar). It holds 0.18 l (0.0475 USgal) of useable fluid when it is full (at 3000 psi (206 bar)). A gas charging valve 2071GM and a pressure gage 2072GM are installed on the accumulator.
　
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