TM 55-1510-222-10
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 in the overhead
control panel (fig. 2-13). The single speed blower
operates automatically through the N1 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. Automatic Heating Mode.
1.
Bleed air valve switches - OPEN, LEFT
and RIGHT.
2.
Cabin temperature mode selector switch
- AUTO.
3.
Cabin temperature control rheostat - As
required.
4.
Cabin, cockpit and defrost air knobs -
As required.
c. Manual heating mode.
1.
Bleed air valve switches - OPEN, LEFT
and RIGHT.
2.
Cabin temperature mode selector switch
- MAN HEAT.
3.
Vent blower switches - As required.
4.
Manual
temperature
switch
-
As
required.
5.
Cabin, cockpit and defrost air knobs -
As required.
(1)
Cargo Door Radiant Heat. 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.
2-69.
AIR CONDITIONING SYSTEM.
a.
Description. Cabin air conditioning is
provided by a refrigerant gas vapor cycle refrigeration
system, consisting of a belt driven, engine mounted
compressor, installed on the #2 engine accessory
section, refrigerant plumbing, N1 speed switch, high and
low pressure protection switches, condenser coil,
condenser under-pressure switch, condenser 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
condenser 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 in the overhead
circuit breaker panel (fig. 2-6), protects the compressor
clutch circuit.
(1)
Forward
evaporator.
The
forward evaporator and blower supplies airflow for the
cockpit, forward ceiling outlets, and forward floor outlets.
The forward evaporator blower has a high speed which
can be selected by setting the VENT BLOWER FWD
switch, located in 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 beneath the aisleway.
(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 airflow for the aft ceiling outlets, rear floor
outlets, and toilet compartment. The rear evaporator
blower is protected by a circuit breaker located in the
DC power distribution panel, located beneath the
aisleway.
(3)
High and low pressure limit
switches. High and low pressure limit switches are
provided to prevent compressor operation beyond
operational limits. When the low or high pressure
switches are activated, compressor operation will be
terminated. When compressor operation has been
terminated by limit switch activation, the system should
be thoroughly checked before returning it to service.
(4)
Thermal
sense
switch.
A
thermal sense switch is installed on the forward
evaporator. This sense switch actuates a hot gas
bypass valve which bypasses a portion of the refrigerant
from the forward evaporator, thereby preventing icing of
the evaporator.
(5)
Condenser blower. A vane-
axial blower
2-59
