PIPER CHEROKEE
SIX SERVICE MANUAL
SECTION
XIII
ACCESSORIES AND UTILITIES
13-1. AIR CONDITIONING INSTALLATION.
13-2.
DESCRIPTION. Components used
for this installation consist of a two
cylinder,
piston type
compressor supported
by special bracketry
located on
the front of the engine.
The
compressor is driven
by a V-belt connected
to the engine
ring gear which
drives the
compressor through
a magnetic
clutch. An evaporator
mounted in
a fabricated housing
along with the
receiver-dehydrator,
circulating fan,
thermal expansion
valve and related
plumbing
is mounted in
the rear of the cabin
aft of the baggage
area. The condenser
is
installed
in the bottom portion
of the fuselage
tail section and
is hinge mounted to
allow its
extension into the
airstream during system operation. The
condenser is electrically operated
to provide
two positions automatically,
as required
(system on -fully
extended and system
off - fully retracted). The system is protected by a Ranco type pressure switch which
automatically controls
the condenser maximum head pressures
by temporarily de-clutching
the compressor in
the event the pressure
becomes excessively
high. The controls
are located
in the aircraft
instrument panel
adjacent to the
heater and defroster
levers, and consist
of an
air conditioning
ON-OFF control,
a three position
fan control (LOW
- MED - HIGH)
to
govern the cold air velocity
and a temperature
control.
The system
design is such
that there is no
increase in drag
to the aircraft.
during its
take-off flight conditions.
During maximum power demands
the compressor is de-clutched
and the
condenser door is automatically
retracted.
13-3. AIR CONDITIONING SYSTEM OPERATION.
The
air conditioning
system
in this aircraft
is a recirculating,
independent
unit.
It filters,
dehumidifies and
cools the air as it cycles
through the evaporator.
The unit
is operated from
controls mounted
on the
right side
of the instrument
panel.
On earlier
models the
ai-
conditioning master switch has three positions: "FAN only, OFF and AIR COND," On later
models the switch has two positions: "ON and OFF" When the "AIR COND" position is
selected the compressor clutch engages, the condenser scoop opens and the circulating fan is
turned on. The temperature is controlled by a thermostat operated by the temperature
control
selector. A three position fan switch
(LOW - MED - HIGH) operates the blower.
The
fan may be operated to circulate air without using the air conditioning unit.
The
air conditioning system uses Refrigerant
12 as the refrigerant. The refrigerant
enters
the compressor as a vapor. The compressor pressurizes the heat-laden vapor until its pressure
and heat reach a point that is much hotter than the outside air and pumps the vapor to the
condenser where it cools and changes to a liquid. The liquid then passes to the
receiver-dehydrator. Its function is to filter, remove any moisture and insure a steady flow
of liquid refrigerant into the evaporator through the expansion valve. The expansion valve is
a temperature controlled
metering valve which regulates the
flow of the liquid refrigerant to
the evaporator. The evaporator absorbs the heat from the air passing over the coils. From
the evaporator the refrigerant vapor
returns to the compressor where the
cycle is repeated.
Revised: 7/29/77 ACCESSORIES AND UTILITIES
3G10
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