AAON SA-070 - Manual (Page 17)

17
Storage
If installation will not occur immediately
following delivery, store equipment in a dry
protected area away from construction
traffic and in the proper orientation as
marked on the packaging with all internal
packaging in place. Secure all loose-shipped
items.
Direct Expansion (DX) Systems
All water-cooled condenser DX systems are
factory assembled, leak tested, charged with
R-410A refrigerant, and run tested.
All DX systems include evaporator coils,
liquid line filter dryers, thermostatic
expansion
valves (TXV), and scroll
compressors. Compressors are equipped
with a positive pressure forced lubrication
system.
Never turn off the main power supply to the
unit, except for servicing, emergency, or
complete shutdown of the unit. When power
is cut off from the unit crankcase heaters
cannot prevent refrigerant migration into the
compressors. This means the compressor
may cool down and liquid refrigerant may
accumulate
in the compressor. The
compressor is designed to pump refrigerant
gas and damage may occur when power is
restored.
If power to the unit must be off for more
than an hour, turn the thermostat system
switch to "OFF", or turn the unit off at the
control panel, and leave the unit off until the
main power switch has been turned on again
for at least 24 hours for units with
compressor crankcase heaters. This will give
the crankcase heater time to clear any liquid
accumulation out of the compressor before it
is started.
Always control the unit from the thermostat,
or control panel, never at the main power
supply, except for emergency or complete
shutdown of the unit.
During the cooling season, if the airflow is
reduced due to dirty air filters or any other
reason, the cooling coils can get too cold
which will cause excessive liquid to return
to
the compressor. As the liquid
CRANKCASE HEATER
Some units are equipped with
compressor
crankcase heaters,
which should be energized at least
24 hours prior to cooling operation, to
clear any liquid refrigerant from the
compressors.
CAUTION
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