WARNING: Hazardous voltage. Only qualified
personnel must install the electrical service. Dis-
connect and Lock Out all incoming power sources
before connecting to electrical service.
WARNING: This appliance must be permanently
grounded in accordance with the National Electrical
Code and local code requirements.
WARNING: For use with copper conductors only.
Typical wiring diagrams are shown on the following
pages FOR REFERENCE. Always refer to the wir-
ing diagram on the air handling unit for actual wir-
NOTE: CHECK MOTOR RATING PLATE FOR
CORRECT LINE VOLTAGE.
Connect electrical service to unit. Refer to unit wir-
For power supply connection, route field power wir-
ing L1 and L2 and connect either:
1. Unit Without EH: to field-provided and installed
disconnect switch and from switch to power
entry (unit side) and to unit power leads inside
the unit electrical section; or
2. Unit With EH: into the unit through power entry
(unit side) and then to the factory installed pow-
er switch inside the electrical section (see Fig-
ure 9). Note: power switch looks like a circuit
breaker but does not provide overload pro-
tection. Power switch provided only with elec-
tric heater (field kit or factory installed). NOTE:
When electric heat greater than 10kW is pro-
vided, two power supply circuits are required,
as shown on the wiring diagram.
Refer to nameplate or Electrical Ratings (page 28)
for FLA, maximum overcurrent protection device
(MOPD) and minimum circuit ampacity (MCA). Also
refer to wiring diagram affixed to unit to make con-
trol and power wiring connections. For new heater
installation, mark the nameplate label with the
matching heater kW rating. Label is located on the
exterior of the front top panel.
NOTE: Installer is responsible for power wiring and
branch circuit over current protection.
Control Voltage Wiring
Control voltage wiring may enter the unit at the con-
trol box located behind the blower access door, or
other convenient location. Control voltage wiring
NEVER enter an enclosed fan cabinet or reach into
a unit while the fan is running.
LOCK OPEN AND TAG the fan motor power dis-
connect switch before working on a fan. Take fuses
with you and note removal on tag. Electric shock
can cause personal injury or death.
LOCK OPEN AND TAG the electric heat coil power
disconnect switch before working on or near heat-
Failure to follow these warnings could lead to per-
sonal injury or death.
Use only copper conductors for field-installed elec-
trical wiring. Unit terminals are not designed to
accept other types of conductors.
Do not allow wiring to touch the refrigerant tubing,
compressor, or any moving parts of the fan.
Make wiring connections in accordance with the
system wiring system diagram and these instruc-
tions. Wrong wiring may cause improper operation
or unit damage!
Unauthorized changes in the internal wiring can be
very dangerous. The manufacturer will accept no
responsibility for any damage or malfunction that
occurs as a result of such unauthorized changes.
leads exit the bottom of the control box and are
ready for field-connection.
CAUTION! To prevent malfunction of the air condi-
tioner caused by electrical noise, route control wiring
and inter-unit control wiring SEPARATELY FROM
THE POWER WIRING!
Unit with Electric Heat
Page 17 of 60
MMD IOM 1.2 11-10-2020