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TM 9-4120-389-14
(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.
WARNING
When using compressed air, wear safety glasses or goggles. Dirt can be blown
into your eyes.
(5)
Remove the dehydrator (filter-drier), and blow down each leg of the refrigeration system. To
do this, connect a cylinder of dry nitrogen to each dehydrator 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 dehydrator fittings with a jumper, manufactured from refrigerant tubing and
fittings.
(7)
Clean system by back-flushing with liquid R-11 (Item 12, 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.
NOTE
An unused dehydrator or other suitable medium may be used as a 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.
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