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 (c)  Monitor the ENG DUCT PRESSURE for the applicable engine(s).
 1)  When the pressure decreases to 13 psig, put the NACELLE ANTI-ICE SWITCH, for the applicable engine(s) to the OFF position.
 NOTE: The nacelle anti-ice valve moves to the closed
____ position when the duct pressure goes to 13 psig.
 (d)  
Monitor the engine duct pressure.

 (e)  
If the leakage does not decrease fast enough, do one of these two procedures:

 NOTE: The engine duct pressure can slowly decrease to 0
____ psig because of the usual leakage from the duct couplings.
 1)  If the left half of the thrust reverser is open, turn the manual override drives on the PRV and the HPSOV to the OPEN position. a) Hold the PRV and the HPSOV in the OPEN position at the
 same time. b) Let the valves go to the CLOSED position.
 2)  If the left thrust reverser half is not open, manually open the nacelle thermal anti-ice (TAI) valve (Fig. 201): a) Open the NACELLE ANTI-ICE circuit breaker for each
 applicable engine(s). b) Open the nacelle TAI valve access door on the applicable engine(s). c) Turn the nacelle anti-ice valve manual override drive to the OPEN position. d) Hold the valve in the OPEN position momentarily and
 then put the valve in the CLOSED position. e) Close the nacelle TAI access door. f) Close the NACELLE ANTI-ICE circuit breakers.
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SEE A
MANUAL OVERRIDE DRIVE
SWITCH ACTUATING LEVER
B
PRESSURE REGULATING VALVE (PRV)
SEE B
FWD HIGH PRESSURE
SHUTOFF VALVE
A
(HPSOV)
Engine Bleed Air Duct Pressure Release
Figure 201 (Sheet 1)

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Engine Bleed Air Duct Pressure Release
Figure 201 (Sheet 2)

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 PNEUMATIC SYSTEM HEALTH CHECK (PW 4000) - ADJUSTMENT/TEST
_________________________________________________________
 1.  General
_______
 A.  These procedures use the Pneumatic Health Check Test Box to check the pneumatic system components for proper operation.
 NOTE: If you replace a component you can continue the test from that
____
 location or start the test again.

 B.  This procedure will check the power supply, the sense lines (to and from the component) and opening/closing pressures for the following components:
 (1)  
High Pressure Shutoff Valve (HPSOV)

 (2)  
High Pressure Controller (HPC)

 (3)  
Pressure Regulating Valve (PRV)

 (4)  
Pressure Regulating Valve Controller (PRV controller)

 (5)  
Pressure Regulating Shutoff Valve (PRSOV)

 (6)  
Fan Air Modulation Valve (FAMV)
　
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