AAON SA-070 - Manual (Page 35)

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Example:
(221V+230V+227V)/3
= 226V, then
100*(226V-221V)/226V = 2.2%, which
exceeds the allowable imbalance.
Check voltage imbalance at the unit
disconnect switch and at the compressor
terminal. Contact your local power company
for line voltage corrections.
Installing contractor must check for proper
motor rotation and check blower motor
amperage listed on the motor nameplate is
not exceeded. Motor overload protection
may be a function of the variable frequency
drive (VFD) and must not be bypassed.
Wire control signals to the unit’s low
voltage terminal block located in the
controls compartment.
If any factory installed wiring must be
replaced, use a minimum 105°C type AWM
insulated conductors.
Thermostat Control Wiring
If a thermostat is used for unit control,
thermostat should be located on an inside
wall 4-5 feet above the floor where it will
not be subjected to drafts, sun exposure, or
heat from electrical fixtures or appliances.
Control wiring must deliver adequate
voltage to components to assure proper
operation. Control voltage returning from
controller circuit must be a minimum of 21
VAC. To assure proper wiring use the
following chart to determine the allowable
wiring distances.
Table 5 - Control Wiring
Wire Size (Stranded)
- Copper Conductors
Only Total Wire Distance
Allowable
20 AWG 200 ft
18 AWG 350 ft
16 AWG 500 ft
14 AWG 750 ft
12 AWG 1250 ft
Total Wire Distance Allowable =
(Quantity of Control Wires) x
(Control Wire Distance)
Take the total wire distance allowable and
divide by the number of wires to be
connected. This indicates the distance
allowable for that size wire. The wiring to
the unit must not exceed the total wire
distance allowable. If the voltage at the
connectors is less than 21 VAC, isolation
relays must be installed. If under external
control 21 VAC must be field verified.
All external devices must be powered via a
separate external power supply.
Rotation must be checked on all
MOTORS AND COMPRESSORS of
three phase units. Supply fan motors
should all be checked by a qualified
service technician at startup and any
wiring alteration should only be made
at the unit power connection.
CAUTION
Scroll compressors are directional
and will be damaged by operation in
the wrong direction. Low pressure
switches on compressors have been
disconnected after factory testing.
Rotation should be checked by a
qualified service technician at startup
using suction and discharge pressure
gauges and any wiring alteration
should only be made at the unit
power connection.
CAUTION