AAON SA-070 - Manual (Page 48)

48
Packaged DX Cooling Operation and
Control
When a call for cooling (G and Y1, Y2, etc.)
is made the supply fan motors and
compressors will energize.
Maintenance
(See back of the manual for maintenance
log.)
At least once each year, a qualified service
technician should check out the unit. Supply
fans, evaporator coils and air filters should
be inspected monthly.
Periodically during operation, it is necessary
to perform routine service checks on the
performance of the unit. This includes
checking of the air flow, the air filters,
condenser water flow and refrigerant charge.
See Startup section for information on air
flow adjustment and refrigerant charge
adjustment.
DX Cooling
Set unit controls to cooling mode of
operation with supply fans on. Check the
fans
for correct operating direction,
amperage and voltage. Check compressor
operation, rotation, amperage and voltage to
the unit nameplate (check the amperage on
the load side of the compressor contactor).
Condensate Drain Pans
Drain pans will have moisture present and
require
periodic cleaning to prevent
microbial growth. Cleaning of the drain pans
will also prevent any possible plugging of
the drain lines and overflow of the pan itself.
Cleaning of the drain pans and inside of the
unit should be done only by qualified
personnel.
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
Improper installation, adjustment,
alteration, service or maintenance
can
cause property damage,
personal injury or loss of life. Startup
and service must be performed by a
Factory Trained Service Technician.
A copy of this IOM should be kept
with the unit.
WARNING
Electric shock hazard. Shut off all
electrical power to the unit to avoid
shock hazard or injury from rotating
parts.
WARNING
COMPRESSOR CYCLING
5 MINUTE MINIMUM OFF TIME
To prevent motor overheating
compressors must cycle off for a
minimum of 5 minutes.
5 MINUTE MINIMUM ON TIME
To maintain the proper oil level
compressors must cycle on for a
minimum of 5 minutes.
The cycle rate must not exceed 6
starts per hour.
WARNING