1)The flow control valve closed and auto relays and
air/ground relay form a logic circuit for the R429 fan
relay and are in the air conditioning accessory units
(ACAU). This logic looks at pack flow conditions. If
one (L or R) of the pack valve closed relays (pack off) is
energized, the recirculation fan operates to increase
cabin ventilation. If one (L or R) of the pack valves
have their auto relays energized, the recirculation fan
operates.
The air conditioning overboard exhaust valve reconfig
cont circuit breaker is for unpressurized dispatch. If
the circuit breaker is open, the bypass circuit enables
the recirculation fan to operate if the smoke control
relay R648 energizes. The smoke control relay is
energized during these conditions:
- Left or right pack switch is in HIGH
- Airplane is in the air
- R RECIRC FAN switch is off.
2) Related to the normal controller for each pack ie. L pack controller = normal control for l pack.
3) AIR CONDITIONING - TEMPERATURE CONTROL - UNBALANCED MODE
General Description
The unbalanced mode is when the flight compartment trim
air system fails or the trim air switch is OFF.
There are two unbalanced modes of operation:
- Unbalanced
- Unbalanced average.
Unbalanced
The right pack is controlled to satisfy the colder
demand of the two passenger compartment temperature
zones. The left pack is controlled to satisfy only the
temperature requirements of the flight compartment.
The backup flight compartment cabin temperature sensor
and cabin temperature selector provide the pack demand
signal to the left auto pack control.
The backup flight compartment duct temperature sensor
signal is used to provide a 35F(2C) limit in the flight
compartment duct.
The primary flight compartment cabin temperature sensor
and cabin temperature selector provide the standby pack
demand signal to the right auto pack control.
Unbalanced Average Mode
The unbalanced average mode of operation is activated
if the trim air switch is OFF or if either of the
passenger compartment temperature zones fail.
This mode is the same as the unbalanced mode except for
the right pack. The right pack is controlled to satisfy
the average temperature requirements of the two
passenger compartment temperature zones.
4) The outflow valve has these three motors:
- Two AUTO motors (dc) with electronic actuators controlled by different CPC’s.
- One MANUAL motor (dc).
Normal and standby pack control is identical and actually controller in charge swaps with alternate flights.
Hope you ace it
