Page 21
Electrical
WARNING
ELECTROSTATIC
DISCHARGE
(ESD)
Precautions and
Procedures
Electrostatic discharge can aect
electronic components. Take care
during unit installation and service to
protect the unit’s electronic controls.
Precautions will help to avoid control
exposure to electrostatic discharge
by putting the unit, the control and the
technician at the same electrostatic
potential. Touch hand and all tools
on an unpainted unit surface before
performing any service procedure to
neutralize electrostatic charge.
The unit is equipped with a eld make-up box on the left
hand side of the cabinet. The make-up box may be moved
to the right side of the furnace to facilitate installation. If
the make-up box is moved to the right side, clip the wire
ties that bundle the wires together. The excess wire must
be pulled into the blower compartment. Secure the excess
wire to the existing harness to protect it from damage.
INTERIOR MAKE-UP BOX INSTALLATION
BOX
Right Side
FIGURE 21
WARNING
Fire Hazard. Use of aluminum wire with this product may
result in a re, causing property damage, severe injury
or death. Use copper wire only with this product.
See Figure 22 and Figure 23 for
thermostat wiring in com-
municating applications. Table 8 shows DIP switch and
on-board link settings for non-communicating thermostat
applications. Typical wiring schematic is shown in Figure
24.
1 - 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 Specications bulletin (EHB) and
unit rating plate.
NOTE - Unit nameplate states maximum current draw.
Maximum over-current protection allowed is shown in Table
7.
TABLE 7
SL280UH Maximum Over-Current
Protection (Amps)
060NV36A 15
080NV48B, 080NV60C,
100NV60C
20
2 - Holes are on both sides of the furnace cabinet to
facilitate wiring.
3 - Install a separate (properly sized) disconnect switch
near the furnace so that power can be turned o for
servicing.
4 - Before connecting the thermostat or the power
wiring, check to make sure the wires will be long
enough for servicing at a later date. Remove the
blower access panel to check the length of the wire.
5 - Complete the wiring connections to the equipment.
Use the provided unit wiring diagram and the eld
wiring diagrams shown in table 8 and Figure 24.
Use 18-gauge wire or larger that is suitable for
Class II rating for thermostat connections.
6 - Electrically ground the unit according to local codes
or, in the absence of local codes, according to the
current National Electric Code (ANSI/NFPA No. 70).
A green ground wire is provided in the eld make-up
box.
NOTE - The SL280UNHV furnace contains electronic
components that are polarity sensitive. Make sure that the
furnace is wired correctly and is properly grounded.
WARNING
Electric Shock Hazard. Can cause injury or death. Unit
must be properly grounded in accordance with national
and local codes.
7 - One line voltage “ACC” 1/4” spade terminal is
provided on the furnace integrated control. Any
electronic air cleaner or other accessory rated up to
one amp can be connected to this terminal with the
neutral leg of the circuit being connected to the one
of the provided neutral terminals. See Figure 25
for control conguration. This terminal is energized
when the indoor blower is operating.
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