AAON LN-140 - Manual (Page 23)

23
Low Ambient Operation
If the chiller is ordered for a Low Ambient
application, the liquid system must use a
glycol solution and the piping must be
insulated to be prepared for freezing
conditions. Care must be taken in the source
of electrical power for the heating tape and
thermostat.
Electrical
The
single point electrical power
connections are made in the electrical
control compartment.
The microprocessor control furnished with
the unit is supplied with its own power
supply factory wired to the main power of
the outdoor mechanical room.
Verify the unit nameplate voltage agrees
with the power supply. Connect power and
control field wiring as shown on the unit
specific wiring diagram provided with the
unit.
Size supply conductors based on the unit
MCA rating. Supply conductors must be
rated a minimum of 167°F (75°C).
Route power and control wiring, separately,
through the utility entry. Do not run power
and signal wires in the same conduit.
Protect the branch circuit in accordance with
code requirements. The unit must be
electrically grounded in accordance with
local codes, or in the absence of local codes,
the
current National Electric Code,
ANSI/NFPA 70 or the current Canadian
Electrical Code CSA C22.1.
Power wiring is to the unit terminal block or
main disconnect. All wiring beyond this
point has been done by the manufacturer and
cannot be modified without effecting the
unit's agency/safety certification.
Figure 7 - Front View of Utility Entry and
Power Switch from Control Compartment
Startup technician must check for proper
motor rotation and check fan motor
amperage listed on the motor nameplate is
not exceeded. Motor overload protection
Electric shock hazard. Before
attempting to perform any installation,
service, or maintenance, shut off all
electrical power to the unit at the
disconnect switches. Unit may have
multiple power supplies. Failure to
disconnect power could result in
dangerous operation, serious injury,
death, or property damage.
WARNING
Installing Contractor is responsible
for proper sealing of the electrical
and gas entries into the unit. Failure
to seal the entries may result in
damage to the unit and property.
CAUTION