Page 39
Electrical
WARNING
ELECTROSTATIC
DISCHARGE
(ESD)
Precautions and
Procedures
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.
WARNING
Electric Shock Hazard. Can cause injury or
death. Unit must be properly grounded in
accordance with national and local codes.
WARNING
Fire Hazard. Use of aluminum wire with this product may
or death. Use copper wire only with this product.
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
MAKE-UP
BOX
Right Side
Figure 57
Figure 58 and Figure 59 for wiring in communicating ap-
plications. TABLE 11 shows DIP switch and on-board link
settings for non-communicating thermostat applications.
Typical wiring schematic is shown in Figure 61, 61, 62 and
63.
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
unit rating plate.
NOTE - Unit nameplate states maximum current draw.
Maximum over-current protection allowed is shown in TA-
BLE 10.
TABLE 10
EL297UHV Maximum Over-Current
045V36B, 070V36B,
090V36C, 090V48C,
110V48C
15
090V60C, 110V60C,
135V60D
20
Holes are on both sides of the furnace cabinet to facilitate
wiring.
Install a separate (properly sized) disconnect switch near
Before connecting the thermostat or the power wiring,
check to make sure the wires will be long enough for ser-
vicing at a later date. Remove the blower access panel to
check the length of the wire.
Complete the wiring connections to the equipment. Use
the provided unit wiring diagram. See Figure 61 through
Figure 64. Field wiring diagrams begin on page 44. Use
18-gauge wire or larger that is suitable for Class II rating
for thermostat connections.
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
EL297UHV furnace contains electronic components that
are polarity sensitive. Make sure that the furnace is wired
correctly and is properly grounded.
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 connect-
ed to this terminal with the neutral leg of the circuit being
connected to the one of the provided neutral terminals.
energized when the indoor blower is operating.
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