Page 21
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.
Refer  to  FIGURE  22  for  schematic  wiring  diagram,  eld 
wiring and trouble shooting.
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 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 o 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 and eld wiring diagram shown in 
FIGURE 22. 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 
wire is provided in the eld make-up box.
NOTE - The  EL180UHNE  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.
Accessory Terminals
One line voltage “EAC” 1/4” spade terminal is provided 
on the furnace integrated control. See FIGURE 24 for in-
tegrated control conguration. 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 24 for in-
tegrated control conguration. This terminal is energized 
in the heating mode when the combustion air inducer is 
operating. Any humidier 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 humidier rated at greater than one amp is connected to 
this terminal, it is necessary to use an external relay relay.
One 24V ”H” 1/4” spade terminal is provided on the fur-
nace integrated control. See FIGURE 24 for integrated 
control  conguration.  The  terminal  is  energized  in  the 
heating mode when the combustion air inducer is operat-
ing and the pressure switch is closed. Any humidier rated 
up to 0.5 amp can be connected to this terminal with the 
ground leg of the circuit connected to ground or the ”C” 
terminal.
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.