Electrical Wiring - Greenheck VSU Installation, Operation And Maintenance Manual

Installation of Electrical Wiring
IMPORTANT
Before connecting power to the unit, read and
understand the following instructions and wiring
diagrams. Complete wiring diagrams are attached on
the inside of the control center door(s).
IMPORTANT
All wiring should be done in accordance with the
latest edition of the National Electric Code ANSI/
NFPA 70 and any local codes that may apply. In
Canada, wiring should be done in accordance with
the Canadian Electrical Code.
IMPORTANT
The equipment must be properly grounded. Any
wiring running through the unit in the airstream must
be protected by metal conduit, metal clad cable or
raceways.
CAUTION
If replacement wire is required, it must have a
temperature rating of at least 105ºC, except for an
energy cut-off or sensor lead wire which must be
rated to 150ºC.
DANGER
High voltage electrical input is needed for this
equipment. This work should be performed by a
qualified electrician.
CAUTION
Any wiring deviations may result in personal injury or
property damage. Manufacturer is not responsible
for any damage to, or failure of the unit caused by
incorrect final wiring.
IMPORTANT
Manufacturer's standard control voltage is 24 VAC.
Control wire resistance should not exceed 0.75 ohms
(approximately 285 feet total length for 14 gauge
wire; 455 feet total length for 12 gauge wire). If the
resistance exceeds 0.75 ohms, an industrial-style
plug-in relay should be wired in place of the remote
switch. The relay must be rated for at least 5 amps
and have a 24 VAC coil. Failure to comply with these
guidelines may cause motor starters to chatter or not
pull in, resulting in contactor failures and/or motor
failures.
Determine the Size of the Main Power Lines
The unit's nameplate states the voltage and the unit's
MCA. The main power lines to the unit should be sized
accordingly. The nameplate is located on the outside of
the unit on the control panel side.
Determine the Size of Electric Heater Wiring
An optional electric heater may require a separate
power supply. The power connection should be made
to the factory provided electric heater disconnect and
10 Model VSU Make-Up Air
must be compatible with the ratings on the nameplate,
supply power voltage, phase and amperage. Consult
ANSI/NFPA 70 and CSA C22.1 for proper conductor
sizing.
Connect the Main Power
Connect the main power lines to the disconnect switch
and main grounding lug(s). Torque field connections to
manufacturer's recommendations.
Wire the Optional Convenience Outlet
The convenience outlet requires a separate 115V power
supply circuit. The circuit must include short circuit
protection which may need to be supplied by others.
Wire the Optional Accessories
Reference the ladder diagram on the inside of the
control center door for correct wiring of the following
accessories:
• Selectra Stat
• Room Override
• Blower Switch
• Heat Switch
Wiring to the Selectra Stat should be in separate
conduit or run with shielded cable.
TSCP has number-to-number wiring.
Large evaporative coolers may require a separate
power supply.
Connect Field-Wired Low Voltage Components
Most factory-supplied electrical components are
prewired. To determine what electrical accessories
require additional field-wiring, refer to the unit-specific
wiring diagram located on the inside of the control
center access door.
The low voltage control circuit is 24 VAC and control
wiring should not exceed 0.75 ohms.
Control wires should not be run inside the same conduit
as that carrying the supply power. Make sure that
field-supplied conduit does not interfere with access
panel operation. All low voltage wiring should be run in
conduit wherever it may be exposed to the weather.
If wire resistance exceeds 0.75 ohms, an industrial-
style, plug-in relay should be added to the unit control
center and wired in place of the remote switch (typically
between terminal blocks R and G on the terminal strip).
The relay must be rated for at least 5 amps and have a
24 VAC coil. Failure to comply with these guidelines may
cause motor starters to "chatter" or not pull in which
can cause contactor failures and/or motor failures.
• Indicating Lights
• Dirty Filter Indicator
• TSCP
• KSCP
NOTE
NOTE
NOTE
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