Hudson 1955 Rambler, Техническое и сервисное руководство

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26 TECHNICAL SERVICE MANUAL
ice forms. Such intermittent refrigeration is
an indication of excessive water in the
system. Clogging due to particles of dirt
reduces or stops refrigeration completely
until the dirt is removed. Clogging due to
water is intermittent while that due to dirt
is permanent.
Freon-12 will slowly hydrolyze; that is,
react with water to form Hydrochloric acid or
Hydrofluoric acid. This quickly and seriously
corrodes the metals used in the system. Freon
itself has no corrosive action upon the metals
used in the system, but the aforementioned
reaction with water will corrode the metals.
Corrosive particles in turn break loose and
damage the system.
Water emulsifies with lubricating oil,
meaning the two form an intimate mixture of
exceedingly fine globules of the liquids. This
effect is called "sludging" of the oil and
greatly reduces the lubricating ability of the
oil. Water in a refrigeration system tends
also to make diaphragms and bellows lose their
elasticity and become harder and more brittle.
The best insurance against moisture is to
prevent it from entering the system.
This can be done by keeping all components
sealed prior to installation and during repair
procedures. Should the system be opened for a
service operation, seal the openings and lines
with plastic caps. Follow the procedure
outlined in "Handling of Lines" to rid any of
the parts of suspected moisture.
This system employs the use of Methanol to
prevent water in the system from freezing.
Each pound of Freon-12 requires 2 c.c of
Methanol. This would lower the freezing point
of the water that may be in the system. An
excessive amount of water may upset the
balance, and if the symptoms of water are
present, corrections are necessary. Release
the charge, evacuate the system, and recharge.
Water will be evaporated during the evacuation
process. Also, any air that may be pocketed
in the system will be evacuated at the same
time.
Air which consists of gases that cannot be
condensed in the refrigeration system causes
excessively high pressures in the high side
of the system and reduces the operating
efficiency.
Install gauge set and operate to determine
pressures.
The presence of air is always indicated by
high operating head pressure. (The pressure
should normally not exceed 275 P.S.I. at
normal room temperature.)
This could be confused with an excessive
amount of refrigerant which would also indi-
cate high head pressure; although an excessive
amount of refrigerant would still give ade-
quate cooling effect.
No matter where or how air enters, it will
always end up in the condenser. Air remains
in the condenser and takes up valuable
condensing space.
If the system is known to have the correct
amount of refrigerant, but during operation and using the gauge set the head or high
pressure builds up, air is certain to be in
the system.
PURGING AIR FROM THE SYSTEM
Allow the system to remain idle several minutes
after the compressor has been operating.
The air then may be released through the
discharge service valve on the compressor.
This is done by first making sure that the
valve is shut off to the gauge port. Then
remove the gauge connections. Turn the valve
stem in toward the "cracked" position for a
few moments, thus allowing air to escape
through the gauge port. This should be done
slowly.
Cover the port opening with a cloth when
purging the system of air to prevent refriger-
ant and oil from contacting persons or car.
This procedure should be repeated if it is
apparent that air is still in the system. Care
should be exercised. The system should be
purged slowly to prevent drawing oil out of
the system. Check compressor oil level after
bleeding.
The air may also be bled from the system at
the receiver. "Crack" the top connection flare
nut slightly for a few moments. After you feel
that the air has bled off into the atmosphere,
close the connection and operate the engine
and compressor. Observe the sight glass;
observe the gauges; check the system to see if
it is performing satisfactorily.
If it performs satisfactorily, you have bled
off the air. If not, repeat until the operation
is satisfactory.
PURGING EXCESSIVE REFRIGERANT
FROM SYSTEM
Install the gauge set and operate to determine
pressures.
Excessive amount of refrigerant will be
indicated by high head pressure although the
cooling effect is adequate. Place your hand on
the receiver while the system is running. If
the entire receiver is cold, the indication
would be that the receiver is filled with
liquid refrigerant.
It is possible to bleed the excessive amount
of refrigerant off through the center line of
the gauge manifold set to allow the refrigerant
to bleed into the atmosphere. Open the hand
"valve to the pressure gauge. This will open
the discharge valve to the center gauge line.
The Freon-12 will vaporize upon entering the
atmosphere. Care should be exercised in
allowing the Freon to bleed off. Bleed slowly
to prevent the oil in the system from foaming
and being pulled out of the system.
After you feel you have bled off the amount
of refrigerant necessary to bring it to the
normal charge, close hand valve on pressure
gauge.
Operate the system again and observe the sight
glass and gauges. If the system operates
normally, you have bled off the excessive
amount of refrigerant. If not, the