39OCH0006F08/13/2024
CEILAIR
®
CW & DX IOM
2.7.1.3 THREEPHASE UNITS
WARNING
Verify power is turned off before making electrical connections to the equipment.
NOTE National Electric Code Wiring
All wiring must be provided in accordance with the National Electrical Code and local code requirements.
Use copper conductors only. Wiring terminations may become loose during transit of the equipment;
verify all wiring terminations are secure.
A manual fused disconnect switch must be provided per the National Electrical Code and local codes for
servicing the equipment. Do not mount a shipped-loose, non-fused service switch or customer supplied
disconnect switch to the surface of the unit. If a factory installed, non-fused service switch option was
purchased, the main power and ground connection is located at the switch; otherwise, the main power
connection is located as stated below.
The unit is provided with pilot holes in the main power and control panel for routing field-wiring. These pilot
holes are located near the electric box with a label stating “MAIN POWER INPUT.” Terminate the main power
wires at the line side of the main power distribution block located within the electric box. An equipment
ground lug is provided inside the electric box for terminating an earth ground wire.
NOTE Ground the Unit
Prior to operation, an adequate unit-to-Earth ground must be connected to the electric box.
2.7.1.1 Single-Phase Units 208/230 V
The supply voltage for units designed to operate at 208 V must be within -5% and +10% tolerance. If the
measured supply voltage is 230 V, the unit can operate with a tolerance of ±5% if the following change is
performed: the control transformers within the system must have the primary wire connected to its respective
240 V tap instead of the 208 V tap.
2.7.1.2 Single-Phase Units 277 V
Single-phase units require that the hot leg of power be connected to terminal L1 and the neutral wire to
terminal L2 of the main power distribution block.
2.7.1.3 Three-Phase Units
Three-phase units are designed to have the L1, L2, and L3 supply wires connected to corresponding L1, L2,
and L3 line terminals of the main power distribution block. The unit will operate correctly if the supply wires
are connected in this manner. A ground lug is provided in each unit near the distribution block.
CAUTION
Improper wire connections will result in reverse rotation of the blower motors and compressor (if
applicable) and may eventually result in damage to the compressor. To correct this problem, exchange
any two of the incoming main power wires at the main power distribution block. Do not rewire the unit’s
individual components.
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