(3) If the oil is black, contains sludge and has a burnt acid odor, the compressor failed because of motor burn out
(4) You must clean the entire refrigeration system after a burn out has occurred, since contaminants will have
been carried to many corners and restrictions in the piping and fittings. These contaminants will soon mix with new
refrigerant gas and compressor oil to cause repeated burn outs.
(5) Remove the filter-drier, and blow down each leg of the refrigeration system. To do this, connect a cylinder of
dry-nitrogen to each filter-drier connection, in turn, and open the cylinder shutoff valve for at least 30 seconds at 50 psig
(3.5 kg/cm2) pressure.
(6) Connect the two filter-drier fittings with a jumper, locally manufactured from refrigerant tubing and fittings.
(7) Clean system by back-flushing with liquid R-11 (item 17, Appendix E) from pressurized cylinder or circulating
pump and reservoir with pressure of at least 100 psig.
(8) If pump is used, connect the discharge line of the refrigerant system to the discharge side of pump.
(9) Connect a line containing a filter to the suction line in the unit.
An unused filter-drier or other suitable medium may be used as the filter.
(10) The other end of the temporary suction line should be connected to a small drum or suitable reservoir.
(11) A line should be run from the bottom of the reservoir to the inlet of the pump.
Avoid inhaling fumes and burns from any acid formed by burn out of oil and
refrigerant. Wear gas mask if area is not thoroughly ventilated. Wear protective
goggles or glasses to protect eyes. Wear rubber gloves to protect hands.
(12) Fill reservoir with fluorocarbon refrigerant R-11, and start the pump. Continue filling the reservoir with
refrigerant, R-11, until it begins to pour out of the return line. Continue flushing for at least 15 minutes.
(13) Reverse the pump connections, replace the filter with a new filtering medium, and backflush the system for
an additional 15 minutes.
(14) Remove the pump reservoir, filter, and filter-drier jumper. Place an empty container below the compressor
connections, and connect a cylinder of dry nitrogen to each filter-drier connection in turn. Blow down each leg of the
system at 50 psig (3.5 kg/cm ) for at least 30 seconds.
(15) Disconnect the dry nitrogen cylinder. Cap or plug open connections if compressor and filter-drier are not to
be installed immediately.
g. Compressor installation
The compressor is supplied with a complete charge of oil. Take care that oil is not
lost when handling and installed compressor.
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