AAON LL-540 - Manual (Page 47)

47
Lubrication
All original motors and bearings are
furnished with an original factory charge of
lubrication. Certain applications require
bearings be re-lubricated periodically. The
schedule will vary depending on operating
duty, temperature variations, or severe
atmospheric conditions.
Bearings should be re-lubricated at normal
operating temperatures, but not when
running.
Rotate the fan shaft by hand and add only
enough grease to purge the seals. DO NOT
OVERLUBRICATE.
Air-Cooled Condenser
The air-cooled condenser section rejects
heat by passing outdoor air over the fin tube
coils for cooling of the hot refrigerant gas
from the compressors. The heated air will
discharge from the top of the section
through the axial flow fans.
The condenser coils should be inspected
yearly to ensure unrestricted airflow. If the
installation has a large amount of airborne
dust or other material, the condenser coils
should be cleaned with a water spray in a
direction opposite to airflow. Care must be
taken to prevent bending of the aluminum
fins on the copper tubes.
E-Coated Coil Cleaning
Documented routine cleaning of e-coated
coils is required to maintain coating
warranty coverage.
Surface loaded fibers or dirt should be
removed prior to water rinse to prevent
restriction of airflow. If unable to back wash
the side of the coil opposite of the coils
entering air side, then surface loaded fibers
or dirt should be removed with a vacuum
cleaner. If a vacuum cleaner is not available,
a soft non-metallic bristle brush may be
used. In either case, the tool should be
applied in the direction of the fins. Coil
surfaces can be easily damaged (fin edges
bent over) if the tool is applied across the
fins.
Use of a water stream, such as a garden
hose, against a surface loaded coil will drive
the fibers and dirt into the coil. This will
make cleaning efforts more difficult. Surface
loaded fibers must be completely removed
prior to using low velocity clean water rinse.
A
monthly clean water rinse is
recommended for coils that are applied in
coastal or industrial environments to help to
remove chlorides, dirt, and debris. It is very
important
when rinsing, that water
temperature is less than 130°F and pressure
is than 900 psig to avoid damaging the fin
edges. An elevated water temperature (not to
exceed 130°F) will reduce surface tension,
increasing the ability to remove chlorides
and dirt.
Electric shock hazard. Shut off all
electrical power to the unit to avoid
shock hazard or injury from rotating
parts.
WARNING
High velocity water from a pressure
washer or compressed air should
only be used at a very low pressure
to prevent fin and/or coil damages.
The force of the water or air jet may
bend the fin edges and increase
airside pressure drop. Reduced unit
performance
or nuisance unit
shutdowns may occur.
CAUTION