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para 3-6
using an acid test kit. Excessive acidity (over .05
acid number) in the oil indicates a severe burn-
out. This is the best method of determining the
severity of burnout. Discoloration of the oil may
also indicate a severe burnout.
(2) Discharge a small amount of refrigerant
and smell it. A characteristic burned odor indi-
cates a severe burnout.
(3) Inspect the suction line at the compres-
sor and the liquid line dryer. Any carbon deposits
indicate a severe burnout.
(4) If none of the above indications of se-
vere contamination are found, the burnout can be
classified as mild.
e. Cleanup After a Mild Burnout. When the
burnout is mild, the contaminants can be removed
by changing the liquid line filter-dryer. The pro-
cedure to follow is:
(1) Discharge the refrigerant.
(2) Remove the burned out compressor and
install the replacement.
(3) Remove the dryer and install an over.
size replacement dryer.
(4) Evacuate the system.
(5) Recharge the system and put in opera-
tion.
f. (Clean-up After a Severe Burnout. Complete
cleaning of the system is required.
(1) Dicharge the refrigerant.
(2) Install a filter-dryed in the suction line,
change strainer, as well as changing or installing
an oversize liquid line filter-dryer. In this way
the suction filter-dryer protects the new compres-
sor from any contaminants that may remain in
the system. Leaving a permanent type filter-
dryer in the suction line allows the serviceman to
complete the cleanup at one time. A pressure tap
should be installed upstream of the suction filter-
dryer so that the pressure drop from the tap to
the service valve can be checked after several
hours of operation. A pressure drop in excess of 3
psi is generally considered excessive.
(3) Check the expansion device and clean or
replace it. Replace sight glass.
(4) Remove the burned out compressor and
install the replacement.
(5) Evacuate the system.
(6) Recharge the system and put in opera-
tion.
(7) Check pressure drop across suction fil-
ter-dryer after one hour operation. Change if nec-
essary and evacuate system.
(8) After 8-24 hours operation, change
suction filter-dryer, check odor and color of oil or
test with test kit. Evacuate system.
(9) After 14 days of operation, check color
and acidity of oil. If required, change filter-
6-9
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