Electrical Information
The unit must be electrically grounded in accordance
with the current National Electrical Code, ANSI/NFPA
70. In Canada, use current CSA Standard C22.1,
Canadian Electrical Code, Part 1. In addition, the
installer should be aware of any local ordinances or
electrical company requirements that might apply.
System power wiring must be properly fused and
conform to the local and national electrical codes.
System power wiring is to the unit main disconnect
(door interlocking disconnect switch standard on most
units) or distribution block and must be compatible with
the ratings on the nameplate: supply power voltage,
phase, and amperage (Minimum Circuit Amps - MCA,
Maximum Overcurrent Protection - MOP). All wiring
beyond this point has been done by the manufacturer
and cannot be modified without affecting the unit’s
agency / safety certification.
If field installing an additional disconnect switch, it
is recommended that there is at least four feet of
service room between the switch and system access
panels. When providing or replacing fuses in a fusible
disconnect, use dual element time delay fuses and size
according to the rating plate.
If power supply is desired through bottom of unit, run
the wiring through the curb, cut a hole in the cabinet
bottom, and wire to the disconnect switch. Seal
penetration in cabinet bottom to prevent leakage.
The electric supply to the unit must meet stringent
requirements for the system to operate properly. Voltage
supply and voltage imbalance between phases should
be within the following tolerances. If the power is not
within these voltage tolerances, contact the power
company prior to operating the system.
Voltage Supply:
See voltage use range on the rating
plate. Measure and record each supply leg voltage at all
line disconnect switches. Readings must fall within the
allowable range on the rating plate.
Voltage Imbalance:
In a 3-phase system, excessive
voltage imbalance between phases will cause motors
to overheat and eventually fail. Maximum allowable
imbalance is 2%. To determine voltage imbalance, use
recorded voltage measurements in this formula.
Key:
V1, V2, V3 = line voltages as measured
VA (average) = (V1 + V2 + V3) / 3
VD = Line voltage (V1, V2 or V3) that
deviates farthest from average (VA)
Formula:
% Voltage Imbalance = [100 x (VA-VD)] / VA
Outdoor Air Weatherhood
Outdoor air weatherhood will be factory mounted.
Exhaust Weatherhood
The exhaust weatherhood is
shipped separately as a kit
with its own instructions.
Dampers
Backdraft dampers are always
included as an integral part of
the exhaust hood assemblies.
Motorized outdoor air and exhaust
air dampers are optional and are
factory mounted and wired at
the intake.
Energy Recovery Ventilator
8
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