Greenheck MSX (470658) User Manual

Page 8

Modular Supply Make-Up Air Unit

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 105°C, except for an
energy cut-off or sensor lead wire which must be
rated to 150°C.

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.

1. 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.

2. Provide the Opening(s) for the Electrical

Connection. Electrical openings vary by unit size
and arrangement and are ﬁeld supplied.

3. Connect the Main Power. Connect the main

power lines to the disconnect switch and main
grounding lug(s). Torque ﬁeld connections to
20 in.-lbs.

4. Wire the Optional Convenience Outlet. The

convenience outlet requires a separate 115 volt
power supply circuit. The circuit must include short
circuit protection which may need to be supplied by
others.

5. Wire the Optional Accessories. Reference the

Ladder Diagram on the inside of the control center
door for correct wiring of the following accessories:

• Blower Switch

• Heat Switch

• Indicating Lights

• Dirty Filter Indicator

• TSCP

• KSCP

NOTE

TSCP has number-to-number wiring.

NOTE

Large evaporative coolers may require a separate
power supply.

6. Wire the Optional Evaporative Cooler. Reference

the Ladder Diagram on the inside of the control
center door for correct wiring of the pump and the
optional auto-drain and ﬂush.