TM 1-1510-262-10
(6) Manual temperature control switch. A switch placarded CABIN AIR MANUAL TEMP DECREASE
INCREASE located on the overhead control panel (Fig. 2-13), controls cockpit and mission equipment compart-
ment temperature with the cabin temperature mode selector switch set to the MAN equipment temperature by
providing a means of manually changing the amount that the bleed air bypass valves are opened or closed. To
increase cabin temperature, the switch is held to the INCR position. To decrease cabin temperature, the switch is
held to the DECR position. Approximately 30 seconds, per valve, is required to drive the bypass valves to the fully
open or fully closed position. Only one valve moves at a time.
(7) Forward vent blower switch. The forward vent blower is controlled by the switch placarded VENT
BLOWER FWD AUTO LOW HIGH , located on the overhead control panel (Fig. 2-13). In the AUTO position the
fan will run at low speed except when the cabin temperature mode selector switch is set to the OFF position, in this
case the blower will not operate.
(8) Aft vent blower switch. The aft vent blower is controlled by the switch placarded VENT BLOWER
AFT AUTO ON , located on the overhead control panel (Fig. 2-13). The single speed blower operates automati-
cally through the N 1 switch, when the aft vent blower switch is placed in the AUTO position. The blower operates
continuously when the switch is placed in the ON position with the air conditioner compressor operating. In the OFF
position, the blower will not operate.
b. Operation.
(1)
Automatic Heating Mode.
Bleed air valve switches -- OPEN , LEFT , and RIGHT.
(a)
Cabin temperature mode selector switch -- AUTO.
(b)
(c)
Cabin temperature control rheostat -- As required.
(d)
Cabin, cockpit and defrost air knobs -- As required.
(2)
Manual heating mode.
Bleed air valve switches -- OPEN , LEFT , and RIGHT.
(a)
Cabin temperature mode selector switch -- MAN HEAT.
(b)
(c)
Vent blower switches -- As required.
(d)
Manual temperature switch -- As required.
(e)
Cabin, cockpit and defrost air knobs -- As required.
(3) Cargo Door Radiant Heat (If installed). A radiant heat panel is provided inside the cargo door to
provide supplemental heating in the aft cabin area. The heat panel is operating whenever the cabin temperature
mode switch is in the manual heat mode, or in the automatic mode with the temperature control system in the heat
mode.
2-73. AIR CONDITIONING SYSTEM.
a. Description. Cabin air conditioning is provided by a refrigerant gas vapor cycle refrigeration system, consist-
ing of a belt driven, engine mounted compressor, installed on the #2 engine accessory section, refrigerant plumbing,
N 1 speed switch, high and low pressure protection switches, condenser coil, condenser under-pressure switch, con-
denser blower, forward and aft evaporators, receiver-dryer, expansion valve and a bypass valve. The plumbing from
the compressor is routed through the right inboard wing leading edge to the fuselage and then forward to the con-
denser coil, receiver-dryer, expansion valve, bypass valve, and forward evaporator, which are located in the nose of
the aircraft. The 7.5-ampere circuit breaker, placarded AIR COND CONTR , located on the overhead circuit breaker
panel (Fig. 2-12), protects the compressor clutch circuit.
(1) Forward evaporator. The forward evaporator and blower supplies airlow for the cockpit, forward ceil-
ing outlets and forward loor outlets. The forward evaporator blower has a high speed which can be selected by
setting the VENT BLOWER FWD switch, located on the overhead control panel (Fig. 2-13), to the HIGH position.
The forward vent blower is protected by a circuit breaker located in the DC power distribution panel, located be-
neath the aisle way.
(2) Aft evaporator. The aft evaporator and blower are located in the fuselage center aisle equipment bay,
aft of the rear spar. Environmental air is circulated through the evaporator in either manual or automatic control
modes. The rear evaporator supplies airlow for the aft ceiling outlets, rear loor outlets, and toilet compartment.
2-67
