Automatic Flow Control Valve Installation 500
21-58-31Page 402 Figure 401 BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details. Feb 20/92
AIRFLOW DETECTOR - REMOVAL/INSTALLATION
1. Remove Airflow Detector
A. Open EQUIP COOLING CONT circuit breaker on circuit breaker panel P18.
B. Disconnect airflow detector electrical connector. (See figure 401.)
C. Remove four mounting screws.
D. Remove airflow detector from blower inlet duct.
2. Install Airflow Detector
A. Place airflow detector in mounting position with electrical receptacle facing inboard.
B. Install four mounting screws.
C. Connect airflow detector electrical connector.
D. Close EQUIP COOLING CONT circuit breaker on circuit breaker panel P18.
E. Test equipment cooling system. Refer to 21-58-0.
500
Feb 15/69 BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details. 21-58-41 Page 401
Airflow Detector Installation 500
21-58-41Page 402 Figure 401 BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details. May 15/67
EQUIPMENT COOLING BLOWER CHECK VALVE - REMOVAL/INSTALLATION
1. General
A. Check valves are installed downstream of both the equipment cooling main and alternate blowers. (See 21-58-11, figure 401.) Instructions for removing and installing either one are the same.
2. Remove Equipment Cooling Blower Check Valve
A. Remove equipment cooling blower. Refer to 21-58-11 or 21-58-21.
B. Loosen clamps and remove check valve from flexible duct.
3. Install Equipment Cooling Blower Check Valve
A. Install check valve on flexible duct with clamps.
B. Install equipment cooling blower. Refer to 21-58-11 or 21-58-21.
500
Nov 15/68 BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details. 21-58-51 Page 401
CONDITIONED AIR TEMPERATURE CONTROL SYSTEMS - DESCRIPTION AND OPERATION
1. General
A. Conditioned air temperature control covers that portion of the air conditioning system that starts, regulates, and shuts down air conditioning equipment to provide a selected temperature in the control and passenger cabins. Two sets of controls are provided. One set controls the left mix valve for control cabin temperature regulation. The other controls the right mix valve and provides for the passenger cabin. Normally each system functions automatically according to selections made on the forward overhead panel. Separate manual control systems are provided as an alternate method for raising or lowering control and passenger cabin temperature.
B. Controlling the temperature in the cabins is accomplished by controlling the temperature of air entering the cabins. Air conditioning operation begins when the pack switches are turned on. The switches open the pack valves permitting bleed air from the pneumatic system to enter the air conditioning system.
C. When the pack valve is opened the pack valve closed limit switch opens to de-energize the pack valve closed relay. When the relay is de-energized, contacts within the relay close to initiate all temperature control and overheat protection circuits in the air conditioning system.
D. Downstream of the pack valves part of the air branches off and passes forward to the mixing chamber and the remainder passes through the air cycle system to be cooled before going to the mixing chamber. The proportioning of air through the system depends on the position of the air mix valve. The mix valve regulates hot air bypassing the air cycle system and air going through the air cycle system. This air is recombined later in proper proportions at the mix chamber. The position of the valve depends on signals from the temperature control system regulator according to the temperature of the air in the main distribution manifold compared with that requested by the temperature selector.
E. During automatic operation a regulation system continuously monitors cabin temperature, duct temperature, and changes in cabin supply air temperature to keep the cabins at the selected temperature level. During manual operation the mix valve changes position as a result of direct electrical control. The indicating system permits monitoring of cabin temperature, cabin supply duct temperature, and mix valve position.
500
Aug 15/67 BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details. 21-61-0 Page 1
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