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INTERIOR MAKE-UP BOX INSTALLATION
Right Side
BOX
FIGURE 29
Refer to FIGURE 30 for schematic wiring diagram and for
field wiring.
The power supply wiring must meet Class I restrictions.
Protected by either a fuse or circuit breaker, select circuit
protection and wire size according to unit nameplate.
CAUTION
Failure to use properly sized wiring and circuit
breaker may result in property damage. Size wiring
and circuit breaker(s) per Product Specifications
bulletin (EHB) and unit rating plate.
WARNING
Fire Hazard. Use of aluminum wire with this product
may result in a fire, causing property damage,
severe injury or death. Use copper wire only with
this product.
NOTE - Unit nameplate states maximum current draw.
Maximum over-current protection allowed is 15 AMP.
Holes are on both sides of the furnace cabinet to facilitate
wiring.
Install a separate (properly sized) disconnect switch near
the furnace so that power can be turned off for servicing.
Before connecting the thermostat, check to make sure
the wires will be long enough for servicing at a later date.
Make sure that thermostat wire is long enough to facilitate
future removal of blower for service.
Complete the wiring connections to the equipment. Use
the provided unit wiring diagram and the field wiring dia-
gramshown in FIGURE 30. Use 18-gauge wire or larger
that is suitable for Class II rating for thermostat connec-
tions.
Electrically ground the unit according to local codes or, in
the absence of local codes, according to the current Na-
tional Electric Code (ANSI/NFPA No. 70). A green ground
wire is provided in the field make-up box.
NOTE - The ML180UHV furnace contains electronic com-
ponents that are polarity sensitive. Make sure that the fur-
nace is wired correctly and is properly grounded.
Accessory Terminals
One line voltage "ACC" 1/4" spade terminal is provided
on the furnace integrated control. See FIGURE 31 for in-
tegrated control configuration. This terminal is energized
when the indoor blower is operating. Any accessory rated
up to one amp can be connected to this terminal with the
neutral leg of the circuit being connected to one of the pro-
vided neutral terminals. If an accessory rated at greater
than one amp is connected to this terminal, it is necessary
to use an external relay.
One line voltage "HUM" 1/4" spade terminal is provided
on the furnace integrated control. See FIGURE 31 for in-
tegrated control configuration. This terminal is energized
in the heating mode when the combustion air inducer is
operating. Any humidifier rated up to one amp can be con-
nected to this terminal with the neutral leg of the circuit be-
ing connected to one of the provided neutral terminals. If
a humidifier rated at greater than one amp is connected to
this terminal, it is necessary to use an external relay relay.
Generator Use - Voltage Requirements
The following requirements must be kept in mind when
specifying a generator for use with this equipment:
•
The furnace requires 120 volts + 10% (Range: 108
volts to 132 volts).
•
The furnace operates at 60 Hz + 5% (Range: 57 Hz
to 63 Hz).
•
The furnace integrated control requires both po-
larity and proper ground. Both polarity and proper
grounding should be checked before attempting to
operate the furnace on either permanent or tempo-
rary power.
•
Generator should have a wave form distortion of
less than 5% total harmonic distortion.
Thermostat
Install the room thermostat according to the instructions
provided with the thermostat. If the furnace is being
matched with a heat pump, refer to the FM21 installation
instruction or appropriate dual fuel thermostat instructions.
Indoor Blower Speeds
1 - When the thermostat is set to "FAN ON," the indoor
blower will run continuously at approximately 38%
of the second stage cooling speed when there is no
cooling or heating demand.
2 - When this unit is running in the heating mode,
the indoor blower will run on the heating speed
designated by the positions of DIP switches 3 and 4.
3 - When there is a cooling demand, the indoor blower
will run on the cooling speed designated by the
positions of DIP switches 5 and 6.
Page 23
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