COMPONENT DESCRIPTION
Integrated ECS Temperature
Controller
The Integrated ECS Temperature Controller is
located in the tailcone. It contains three cir-
cuit cards that perform three separate func-
tions. (1) One function is to operate the low
limit temperature control valve on the ECU to
prevent moisture from freezing in the water
separator. (2) Another function of the
Integrated Controller is Wing/Stab anti-icing
control. (3) The third function is to control the
temperature of the bleed-air entering the cock-
pit and cabin for ventilation and pressuriza-
tion.
The temperature control circuit card performs
two separate and independent functions of
controlling the cockpit temperature and cabin
temperature. Additionally, the two function-
ally separated circuits of the controller can op-
erate in an automatic or a manual mode, but
both must be operated in the same mode. The
automatic and manual modes of temperature
control are powered separately.
Electrical power for the automatic mode is 28
VDC supplied by the right main bus. Power is
supplied through the AUTO TEMP CTRL cir-
cuit breaker in the ENVIRONMENTAL group
on the copilot’s circuit breaker panel. The
manual temperature mode is powered by the
right essential bus through the MAN TEMP
CTRL circuit breaker. Power failure to the
auto or manual circuits would not preclude
the use of the other mode to control cockpit
and cabin temperature.
An electrical failure that results in both engine
generators off-line, sheds the main busses of
the electrical system. Since the auto mode of
temperature control is powered by the right
main bus automatic temperature control will
be lost but temperature control can be regained
by selecting the Manual Temp S/I to ON. If
power fails to the right main bus and the right
essential bus, temperature control via the
Integrated Controller and the temperature con-
trol valves will be lost. The temperature con-
trol valves fail to the full closed (cold) posi-
tion.
The Integrated Controller uses input signals
from the cockpit and cabin temperature sen-
sor, cockpit and cabin duct temperature sen-
sors, and cockpit and cabin temperature
selectors to control the cockpit and cabin tem-
perature control valves (Figure 11-4) in the au-
tomatic mode. Selecting manual disables all
of the temperature sensors and allows the tem-
perature control valves to be operated manu-
ally via the rotation of the temperature selector
knobs.
Cabin/Cockpit Temperature
Sensors
Temperature sensors are mounted in the cabin
and in the cockpit to provide electrical signals
to the Integrated Controller. The cabin tem-
perature sensor assembly contains a small fan
to force cabin air across the sensor and pro-
vide an accurate indication of cabin temper-
ature. In the automatic mode, the Integrated
Controller responds to the sensor signals by
modulating the hot air flow through the cock-
pit and cabin temperature control valves
(Figure 11-4).
Duct Temperature Sensors and
Limiters
Duct temperature sensors and over temp lim-
iter switches are located in the cockpit bleed-
air supply duct and also in the right and left
side cabin supply ducts (Figure 11-4).
The cockpit and cabin duct temperature sen-
sors output signals to the Integrated ECS Temp
Controller. These signals are used for tem-
perature control when operating in the auto-
matic mode, for duct temperature indication,
and to activate a CAS message in the event the
duct temperature exceeds a pre-determined
limit (300° F).
The cockpit duct temp sensor and the left side
cabin temp sensor each have two functions. In
11-5
FOR TRAINING PURPOSES ONLY
LEARJET 45 PILOT TRAINING MANUAL
FlightSafety
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