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MAINTENANCE MANUAL
L PACK TEMP CONTROLLER
LEFT SYSTEM SHOWN, RIGHT SYSTEM SIMILAR
Pack Bite Operation Figure 17 (Sheet 1)
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(2)
The BITE test will show which component has failed. The controllers have switches, lights, and instructions to do the BITE test.
(a)
The switches on the automatic-pack-temperature controllers are used to do the BITE test. With no critical failure, any switch except RESET can be pushed or canceled at any time. The light above the switch comes on when the switch is in operation. The light and the switch operation will go off if another switch is not pushed within 30 seconds (90 seconds for the VERIFY switch). If another switch is pushed, the previous switch operation is canceled. Here is a list of the switches and their function: 1) The PRESS/TEST switch causes all of the controller lights
to come on. This makes sure that all the lights work and power is applied correctly.
2) The BIT switch indicates any components that failed in the last flight or on the ground.
3) The PREVIOUS FLIGHTS switch indicates any components that failed in the previous nine flights.
4) The VERIFY switch does a check to make sure that no components are presently failed. If a component is failed at this time, the appropriate fault light will come on.
5) The RESET switch only operates when the VERIFY switch is pushed and the GO light is on. It will erase all the faults in the memory and unlatch the fault relay.
(b) The lights on the automatic-pack-temperature controller are used to show which component has failed. The lights will come on when the BIT, the PREVIOUS FLIGHTS, or the VERIFY switch is pushed. Here is a list of the lights and what type of failure can cause them to come on:
NOTE: The failure could also be caused by an aircraft
____ wiring problem between the controller and the appropriate component.
1) The GO light comes on when a switch is pushed and no failure has occurred.
2) The CONTROLLER FAULT light comes on when a critical failure occurs.
NOTE: When the CONTROLLER FAULT light is on, the other
____ fault lights will not come on.
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3) The PACK SENSOR, the MIX MANF SENSOR, the ZONE SENSOR, or the COMPRESSOR SENSOR light comes on when a short or open circuit occurs in the sensor.
4) The ALTITUDE SWITCH light comes on when a pressure capsule switch or a electrical switch failure occurs.
5) The RAM INLET ACTR, the RAM OUTLET ACTR, the LOW LIMIT VALVE, or the TEMP CONT VALVE light comes on when an open limit switch circuit, an open feedback potentiometer circuit, or a mechanical failure occurs.
6) The FLOW CONT VALVE light comes on if the torque motor in the valve is open or shorted.
(c) Do the automatic-pack-temperature controller BITE test: 1) Supply the electrical power. 2) Put the applicable (L or R) PACK control selector, on the
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