King Air C90GTi, Pilot Training Manual

Page: 250 / 557

bleed-air valve switches on the copilot’s sub-
panel to the CLOSED position. Closing the
bl e e d - a i r va l ve s p r eve n t s wa r m bl e e d a i r
from entering the cabin area, maximizing
the air conditioner operation.
The heat in the air may either be retained
for cabin heating or dissipated for cooling
pur poses as the air passes through the cen-
ter section to the fuselage. If the environ-
mental bleed-air mixture is too war m for
cabin comfor t, the cabin temperature con-
trol bypass valve (Figure 11-14) routes some
or all of it through the air-to-air heat ex-
changer in the wing center section. The po-
sition of the damper in the cabin temperature
control bypass valve is deter mined by po-
sitioning of the controls in the ENVIRON-
MENTAL g roup on the copilot’s subpanel.
An air intake on the leading edge of the in-
board wing brings ram air into the heat ex-
changer to cool the bleed air.
Depending upon the position of the cabin
temperature control bypass valves, a greater
or lesser volume of the bleed-air mixture
will be routed through or around the heat
exchanger. The temperature of the air flow-
ing through the heat exchanger is lowered as
heat is transfer red to cooling f ins, which
are in tur n cooled by ram air-flow through
the f ins of the heat exchanger. After leav-
KING AIR C90GTi/C90GTx PILOT TRAINING MANUAL
11-7
FOR TRAINING PURPOSES ONLY
11
AIR
CONDITIONING
1. CABIN TEMP
SENSOR
2. CABIN TEMP
SELECTOR
RHEOSTAT
TO CABIN
AIR-TO-AIR
HEAT
EXCHANGER
TO CABIN
AIR-TO-AIR
HEAT
EXCHANGER
AIR CONDITIONER
RH BYPASS
VALVE MOTOR
30 SECONDS
LH BYPASS
VALVE MOTOR
HEAT
HEA
T
COOL
COOL
AUTO TEMP
CONTROLLER
MANUAL
COOL
MODE
SELECTOR
SWITCH
AUTO
MANUAL
HEAT OR
COOL
MANUAL
TEMP
INCR-DECR
SWITCH
Figure 11-14. Air Conditioning System Control Diagram