contaminant particles. They must be flushed with a
liquid. Some refrigerants are better suited for this
purpose than others.
R-11 and R-113 are suited for use with special
flushing equipment. Both have rather high
vaporization points74.7°F for R-11 and 117.6°F for
R-l 13. Both refrigerants also have low closed
container pressures. This reduces the danger of an
accidental system discharge to a ruptured hose or
fitting. R-113 will do the best job and is recommended
as a flushing refrigerant. Both R-11 and R-113 require
a propellant or a pump type of flushing equipment due
to their low closed container pressures. R-11 is
available in pressurized containers. Although not
recommended for regular use, it may become
necessary to use R-11 if special flushing equipment is
not available. It is more toxic than other refrigerants,
and it should be handled with extra care. Currently new
refrigerants are being developed to replace R-11 and
R-113 because these refrigerants will be phased out by
the year 2000.
Use extreme care and adhere to all safety
precautions related to the use of
refrigerants when flushing a system.
System Cleaning and Flushing
When it is necessary to flush a refrigerant system,
the suction accumulator/drier must be removed and
replaced, as it is impossible to clean. Remove the fixed
orifice tube. If a new tube is available, replace the
contaminated one; otherwise, wash it carefully in
flushing refrigerant or mineral spirits and blow it dry.
If it does not show signs of damage or deterioration, it
may be reused. Install new O rings.
Any moisture in the evaporator will be removed
during leak testing and system evacuation following
the cleaning job. Perform each step of the cleaning
procedure carefully as outlined below.
1. Check the hose connections at the flushing
cylinder outlet and flushing nozzle to ensure they are
2. Ensure the flushing cylinder is filled with
approximately 1 pint of R-113 and that the valve
assembly on top of the cylinder is tightened securely.
3. Connect a can of R-12 or R-134a to the
Schrader valve at the top of the charging cylinder. A
refrigerant hose and a special, safety type of refrigerant
dispensing valve are required for connecting the small
can to the cylinder. Ensure all connections are secure.
5. Remove and discard the suction accumulator/
drier. Install a new accumulator/drier and connect it to
the evaporator. Do not connect it to the suction line
from the compressor. Ensure a protective cap is in place
on the suction line connection.
4. Connect a gauge manifold and a discharge
system. Disconnect the gauge manifold.
6. Replace the fixed orifice tube. Install a
protective cap on the evaporator inlet tube as soon as the
new orifice tube is in place. The liquid line will be
7. Remove the compressor from the vehicle for
cleaning and servicing or replacement, whichever is
required. If the compressor is cleaned and serviced, add
the specified amount of refrigerant oil before installing
it on the mounting brackets in the vehicle. Install the
shipping caps on the compressor connections. Install a
new compressor on the mounting brackets in the
8. Back flush the condenser and the liquid line as
a. Remove two O rings from the condenser
inlet tube spring lock coupling.
b. Remove the discharge hose from the
condenser and clamp a piece of (1/2-inch ID) heater
hose to the condenser inlet line. Ensure the hose is long
enough to insert the free end into a suitable waste
container to catch the flushing refrigerant.
c. Move the flushing equipment into position
and open the valve on the can of R-12 or R-134a (fully
d. Back flush the condenser and the liquid line
by introducing flushing refrigerant into the supported
end of the liquid line with the flushing nozzle. Hold the
nozzle firmly against the open end of the liquid line.
e. After the liquid line and condenser have
been flushed, lay the charging cylinder on its side so
R-12 or R-134a will not force more of the flushing
refrigerant into the liquid line. Press the nozzle firmly to
the liquid line and admit the R-12 or R-134a to force all
of the flushing refrigerant from the liquid line and
f. Remove the 1/2-inch hose and clamp from
the condenser inlet connection.