Electrical Connections - Greenheck APEX-200 Installation, Operation & Maintenance Manual

Electrical Connections

The electrical supply must be compatible with that shown on
the nameplate: voltage, phase, and amperage capacity.
Connect power to the unit per the unit specific wiring diagram
located on the inside of the control center access door. The
wiring diagram indicates which electrical accessories were
provided on the unit. The electrical supply line must be properly
fused and conform to local and national electrical codes.
All internal electrical components are pre-wired at the factory. To
determine what specific electrical accessories were provided with
the unit, refer to the unit specific wiring diagram located in the unit
control center. Field electrical connections required:
1) supply power to the main disconnect (See FIGURE 7,
Item #1). A door interlocking safety disconnect is
provided as a standard feature.
2) low voltage control power to the 24 VAC control circuit (See FIGURE 7, Item #7).
IMPORTANT: Use minimum 14 ga. wire for 24 volt control power. Control wire resistance should not
exceed 0.75 ohms (approximately 285 feet total length for 14 ga. wire; 455 feet total length for 12 ga.
wire). 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 control strip — See FIGURE 7, Item #7). 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.
Control wires should not be run inside the same conduit as that carrying the supply power. The unit must be
electrically grounded in accordance with the current National Electrical Code, ANSI/NFPA-70.
Note: Standard factory installed electric pre-heaters and post-heaters have their own disconnect separate
from the unit disconnect. Thus, each electric heater requires its own separate power connection.
Typical Control Center Components
1. Main Disconnect
2. Motor Starter — Exhaust Air Fan #1
3. Motor Starter — Exhaust Air Fan #2
4. Motor Starter — Outdoor Air Fan
5. Energy Wheels Motor Contactor
6. Control Power Transformer
(24 VAC Secondary)
7. 24 VAC Terminal strip
8. Fuses for the control circuit, wheel drive
transformer, and blower motors.
Installation
9. Energy Wheel Motor Transformer (230 VAC
Secondary - for units with primary voltage
greater than 230 VAC) (transformer not shown)
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FIGURE 7: Typical control center components.
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SAFETY DANGER!
Electric shock hazard. Can cause injury or
death. All wiring should be performed by a
qualified electrician. Before attempting to
perform any service or maintenance, turn
the electrical power to unit to OFF at
disconnect switch(es). Unit may have
multiple power supplies.
SAFETY CAUTION!
Verify power before wiring the supply and
control voltage. Greenheck is not
responsible for any damage to, or failure of
the unit caused by incorrect field wiring.
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