Low shelf pressure, applicable plenum pressure OK.
(a)
Check shelf airflow orifices for proper configuration and for leakage through orifices which should be taped closed.
(b)
Check shelf to plenum opening and if obstructed remove obstruction.
NOTE: To check for obstruction remove shelf to plenum
____ fasteners and pull apart only enough to observe opening. Obstruction here may or may not affect plenum pressure depending on the obstruction magnitude.
(c)
Check for excessive leakage where shelf mates to plenum.
Repair if necessary.High plenum pressure.
(a)
Check for obstruction in shelf to plenum opening.
(b)
Check that orifice in plenum outlet duct is not missing, if missing install proper orifice. If not missing check for proper size and replace if necessary.
Any one plenum pressure low.
(a)
Check for obstruction to plenum outlet duct and remove if found. Check also that correct orifice is installed and replace if wrong size.
(b)
Check for excessive leakage where shelf mates to plenum and at
duct to plenum connection. Repair as applicable.Instrument panel cooling tube pressure low (one side).
(a)
Straighten out kink in tube or remove obstruction from tube.
NOTE: If low pressure is observed at all ports of one side
____ straighten out tube or remove obstruction from tube which draws air from that side.
All instrument panel cooling tubes pressure low.
(a)
Repair leaky duct joint or straighten out kink in main
instrument cooling duct.One or more instrument panel or Flight Management Computer System CDU cooling tube pressure(s) high, other panel tube pressure(s) low.
(a)
Condition results from low tube pressure (Ref par. A.(7)).
EFFECTIVITYùùùùùùùùùùùùùùùùùùùùùùùùùùùùùù. APLS WITHOUT EFIS ú
21-58-00
ú ú 04 Page 105 ú Nov 15/91
BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
A
737-300/400/500MAINTENANCE MANUAL
EQUIPMENT COOLING SYSTEM - ADJUSTMENT/TEST
__________________________________________
1. General_______
A. This procedure has these two tasks:
(1)
Operational Test - Equipment Cooling System
(2)
System Performance Test - Equipment Cooling System
B. The operational test of the equipment cooling system will make sure that the system components operate correctly. The system performance test of the equipment cooling system will make sure that there is sufficient airflow to cool all the equipment on the electronic racks.
TASK 21-58-00-705-002
2. Operational Test - Equipment Cooling System___________________________________________
A. General
(1)
For those maintenance activities which require main electrical power on for more than 20 minutes when the outside ambient temperature is more than 100°F (37.8°C), it is recommended to supply conditioned air to the cabin (AMM 21-00-00/201). This will improve the thermal environment for the electrical equipment.
(2)
To cool the equipment on the electronic racks correctly, a balanced airflow must be supplied through the fixed orifice plates on each shelf. If equipment is not installed on the racks, the orifices in these empty trays are covered with a metering plate or tape. The metering plates or tape must be removed before you install additional equipment to prevent the equipment from overheating.
CAUTION: DO NOT ADD EQUIPMENT OR CHANGE THE ORIFICE OPENING ADJUSTMENTS
_______ WITHOUT YOUR ENGINEERING DEPARTMENT APPROVAL. THE EQUIPMENT ON THE RACKS CAN OVERHEAT IF THE ORIFICE OPENINGS ARE NOT ADJUSTED CORRECTLY.
(3) The electronic racks have space for additional equipment if it is necessary. When you add more equipment to the rack, the airflow through the orifices could change for the remaining equipment which can cause the equipment to overheat. Before you add more equipment to the racks, make sure your engineering department approves. You must make sure that the orifices are adjusted correctly to supply sufficient airflow to cool all the equipment. Fig. 501 shows the location of equipment cooling racks.
B. References
中國航空網 m.k6050.com
航空翻譯 www.aviation.cn
本文鏈接地址：737-300 400 500 AMM 飛機維護手冊 空調 AIR CONDITIONING 2(79)
