500 Isolation Valve Control Circuit
Aug 15/69 Figure 4 BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details. 36-11-0 Page 5
5. Pneumatic Ground Service Connector
A. A pneumatic ground service connector and check valve is provided for the connection of a ground pneumatic cart. The connector is located in the right pack bay area on the underside of the fuselage (Fig. 1). Pressurized air from the cart can be supplied for starting. However, before air is supplied for starting, the battery power must be turned on and the air conditioning pack valves switched off. Although maximum pressure and temperature limit of air at ground connector is 60 psig and 4500F respectively, starter limits may be different. For limits of pneumatic starting system, Ref 80-11-0.
B. Pressurized air from the cart can also be used for the air conditioning system during ground operation with no engines running, provided ac power is available on the airplane.
6. Ducts
A. The ducts located in the engine sections are joined to the bleed manifolds by duct ball joints to allow limited motion during operation.
B. The duct sections of the pneumatic system are designed and manufactured slightly short in length in order to compensate for thermal expansion when hot air flows through them.
F89600
Dual Bleed Indicating System Circuit 503
36-11-0 Figure 5 Sep 20/81
Page 6
BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details.
7. Pressure Relief Valves (Fig. 1 and 2)
A. Pressure relief valves are provided to protect pneumatic ducts from excessive pressure. One relief valve is located in the titanium portion of the APU supply duct and relieves at pressures above approximately 80 psi. Two other relief valves, one on the left side of each engine, are located in the downstream sense line for each 13th-stage modulating and shutoff valve. These valves relieve at approximately 106 psi.
8. Engine Bleed Check Valves (Fig. 1)
A. Five check valves are provided in the engine bleed air distribution system. Two check valves are provided at each engine, one in each 8th-stage manifold, to keep air from entering the 8th-stage engine ports during engine start or from high spool bleed. The fifth check valve is located in the APU supply duct to prevent engine bleed air from entering APU.
505
Oct 20/86 BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details. 36-11-0 Page 7
ENGINE BLEED AIR DISTRIBUTION SYSTEM – TROUBLE SHOOTING
1. General
A. The Engine Bleed Air Distribution System directs high temperature compressed air from the engine bleeds to the air conditioning system, to the engine starting system and to the thermal anti-icing system. The system consists of engine bleed valves, an isolation valve, check valves, pressure relief valves, temperature sensing switch and associated ducting.
B. The compression control system comprised of the 13-stage modulating and shutoff valve, high pressure regulator and pack valves is covered in 21-11-0. Refer to 21-11-0, Trouble Shooting for trouble shooting of these components.
C. Prior to accomplishing trouble shooting on the distribution system, perform the Engine Bleed Air Compression Control System – Adjustment Test, trouble shooting as necessary including closing of circuit breakers (Ref 21-11-0).
D. Perform engine bleed air distribution system test (36-11-0, Adjustment/Test) to isolate problems in the system. Then perform the procedures on the following trouble shooting chart to isolate system and component faults.
E. Engine bleed air precooler leakage has been eliminated as a possible fault since any leakage at the precooler great enough to cause system problems should be obvious.
F. Leakage from ducts may be determined by accomplishing duct leakage tests shown in 36-11-0, Adjustment/Test.
G. All trouble shooting procedures are based on the assumption that wiring is ok and that electrical power is available. If the corrective action in the procedure does not correct the problem, check wiring using the wiring diagram. Prior to trouble shooting, check master Dim and Test circuits to ensure panel lights are operable.
500
Nov 15/78 BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details. 36-11-0 Page 101
2. Engine Bleed Air Distribution System Trouble Shooting Chart
TROUBLE PROBABLE CAUSE ISOLATION PROCEDURE REMEDY
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