Thermostatic Switch; Service Valves; Diagnosis And Testing; Safety Precautions - Ford COUGAR 1968 Shop Manual

BART 16-2
-
Air Conditioning
When the blower switch is off or
the functional control lever is not in
an A/C position, the magnetic clutch
cannot be energized for compressor
operation.
When, the blower switch is on and
the functional control lever is in the
cooling range, the magnetic clutch is
controlled by the icing switch which is
controlled by the evaporator tempera-
ture.
THERMOSTATIC SWITCH-
MUSTANG AND COUGAR
The thermostatic switch controls
the operation of the compressor by
controlling the compressor magnetic
clutch. The temperature sensing tube
of the switch is placed in contact with
the evaporator fins. When the tem-
perature of the evaporator becomes
too cold, the thermostatic switch opens
the magnetic clutch electrical circuit.
disconnecting the compressor from
the engine. When the temperature of
the evaporator rises to the upper li-
mit at which the thermostatic switch
is set, the thermostatic switch closes
and energizes the magnetic clutch.
This connects the compressor to the
engine, and cooling action begins
again.
When the ignition switch is off or
the cooling control thermostatic
switch is in the off position, the mag-
netic clutch is not energized, and the
compressor can not operate.
.
When the ignition switch is on (en-
gine running), and the cooling control
is in the cooling range, the magnetic
clutch is energized, the compressor is
connected to the engine and the cool-
ing system is in operation.
SERVICE VALVES
The service valves on the com-
pressor are used to test and service
the cooling system (F~gs. 9 and 10).
The high pressure service valve, mount-
ed at the outlet to the compressor, al-
lows access to the high pressure side
of the system for attaching a service
hose with attached pressure gauge.
The low pressure valve, mounted
at the inlet to the compressor, allows
access to the low pressure side of the
system for attaching a service hose
with attached pressure gauge.
Both service valves may be used
to shut off the rest of the system from
the compressor during compressor
service.
2 DIAGNOSIS AND TESTING
SAFETY PRECAUTIONS
The refrigerant used i n the air
conditioner system is Refrigerant-12.
Refrigerant-I2 is nonexplosive, nonin-
flammable, noncorrosive, has practi-
cally no odor, and is heavier than air.
Although it is classified as a safe
refrigerant, certain precautions must
be observed to protect the parts in-
volved and the person who is working
on the unit.
,
Use only Refrigerant-12. Do not
use refrigerant that was canned for
pressure operated accessories (such
as boat air horns). It is not pure .Re-
frigerant- 12 and will cause a malfun-
ction. Liquid Refrigerant-12, at nor-
mal atmospheric pressures and tem-
peratures, evaporates so quickly that
it contacts. For this reason, extreme
care must be taken to prevent any
liquid refrigerant from coming in con:
tact with the skin and especially the
eyes.
Refrigerant- 12 is readily absorbed
by most types of oil. [t i's therefore
recommended that a bbttle of sterile
mineral oil and a quantity of weak
boric acid solution be kept nearby
when servicing the air conditioning
system. Should any liquid refrigerant
get into the eyes, use a few drops of
mineral oil to wash them out, then
wash the eyes clean with the weak
boric acid solution. Seek a doctor's
aid immediately even though irrita-
tion may have ceased.
Always wear safety goggles when
servicing any part of the refrigerant-
ing system.
The Refrigerant-12 in the system
is always under pressure. Because
the system is tightly sealed, heat ap-
plied to any part would cause this
pressure to build up excessively.
To avoid a dangerous explosion,
never weld, use a blow torch, sol-
der, steam clean, bake body finishes,
or use any excessive amount of heat
on or i n the immediate area of any
part of the air cooling system or
refrigerant supply tank, while they
are closed to the atmosphere whether
filled with refrigerant or not.
The liquid refrigerant evaporates
so rapidly that the resulting refriger-
ant gas will displace the air surround-
ing the area where the refrigerant is
released. To prevent possible suffoca-
tion in enclosed areas, always dis-
charge the refrigerant from an air
cooling system into the garage ex-
haust collector. Always maintain good
ventilation surrounding the work area.
Although Refrigerant-I2 gas, un-
der normal conditions, is nonpoison-
ous, the discharge of refrigerant gas
near an open flame can produce a
very poisonous gas. This gas will
also attack all bright metal surfaces
This poisonous gas is generated
when the flame-type leak detector is
used. Avoid inhaling the fumes from
the leak detector. Make certain that
Refrigerant-12 is both stored and in-
stalled i n accordance with all state
and local ordinances.
When admitting Refrigerant-I2 gas
into the cooling unit, always keep
the tank in an upright pssition. If
the tank is on its side qr upside down,
liquid Refrigerant-I2 will enter the
system and damage the compressor.
In surrounding air temperatures
above 90 degrees F., prolonged engine
idle will result in excessively high com-
pressor pressures.
AIR CONDlT IONER
PERFORMANCE TEST-
FALCON, FAIRLANE, AND
MONTEGO
The performance level of the air
conditioning system can be checked
after performing diagnostic checks
and repairs to determine if the sys-
tem is operating to specifications.
The performance level chart (Fig. I I)
indicates the maximum desireable dis-
charge air temperature in relation to
the ambient (surrounding) air tem-
perature and relative humidity.
The performance level check must
be performed under the following test
conditions.
1. Connect the manifold gauge set
to the compressor service valves. (Re-
fer to Checking System Pressures in
this section).
2. Install a motor driven psychro-
meter (humidity indicator) at the fresh
air intake.
3. Install a dry bulb thermometer
at the center air outlet register (Wes-
ton Model 2261 or equivalent).
4. Operate the engine at 1500 rpm
with the transmission in Park (auto-