Table of Contents
Advertisement
5. Connect field ground wire and factory ground wire to green
ground screw on J- -Box mounting bracket as shown in Fig.
34.
6. Connect power cord power and neutral leads to furnace
power leads as shown in Fig. 33.
7. Attach furnace J- -Box cover to mounting bracket with
screws supplied in loose parts bag. Do not pinch wires be-
tween cover and bracket. See Fig. 34.
BX Cable Installation in Furnace J- - Box
1. Install J- -Box mounting bracket to inside of furnace casing.
See Fig. 34.
2. Route BX connector through 7/8- -in. (22 mm) diameter
hole in casing and J- -Box bracket.
3. Secure BX cable to J- -Box bracket with connectors ap-
proved for the type of cable used.
4. Connect field ground wire and factory ground wire to green
ground screw on J- -Box mounting bracket as shown in Fig.
34.
5. Connect field power and neutral leads to furnace power
leads. as shown in Fig. 33.
6. Attach furnace J- -Box cover to mounting bracket with
screws supplied in loose parts bag. Do not pinch wires be-
tween cover and bracket.
WARNING
!
FIRE, EXPLOSION, ELECTRICAL SHOCK, AND
CARBON MONOXIDE POISONING HAZARD
Failure to follow this warning could result in dangerous
operation, personal injury, death, or property damage.
Do not drill into blower shelf of furnace to route control
wiring. Route any control or accessory wiring to the blower
compartment through external knockouts on the casing.
24- -V Wiring
Make field 24- -v connections at the 24- -v terminal strip. See Fig.
36. Connect terminal Y/Y2 as shown in Fig. 33 for proper cooling
operation. Use only AWG No. 18, color- -coded, copper thermostat
wire.
NOTE: Use AWG No. 18 color-coded copper thermostat wire for
lengths up to 100 ft. (31 M). For wire lengths over 100 ft., use
AWG No. 16 wire.
The 24- -v circuit contains an automotive- -type, 3- -amp. fuse
located on the control. Any direct shorts during installation,
service, or maintenance could cause this fuse to blow. If fuse
replacement is required, use ONLY a 3- -amp. fuse of identical size.
See Fig. 36.
Thermostats
For best results, use a communicating wall control to control this
modulating furnace. A single stage or two- -stage heating and
cooling thermostat can be used with the furnace. The furnace
control board CPU will control the furnace and outdoor unit
staging. A two stage heating and cooling thermostat can also be
used to control the staging. However, full modulating capability
will not be available when the furnace staging is controlled by the
thermostat. Furnace staging will be limited to Minimum and
Maximum inputs or Intermediate and Maximum inputs depending
on the configuration of set-up switches SW1-2 and SW4-2. For
two stage thermostat control of a 2-stage outdoor unit, remove the
ACRDJ jumper from the furnace control board. Refer to typical
thermostat wiring diagrams and the Sequence of Operation section
for additional details. Consult the thermostat installation
instructions for specific information about configuring the
thermostat. See Fig. 36 and 38.
Accessories
(See Fig. 37 and 36.)
1. Electronic Air Cleaner (EAC)
Connect an accessory Electronic Air Cleaner (if used) using
1/4- -in. female quick connect terminals to the two male
1/4- -in. quick- -connect terminals on the control board
marked EAC- -1 and EAC- -2. The terminals are rated for
115VAC, 1.0 amps maximum and are energized during
blower motor operation.
2. Humidifier (HUM)
The HUM terminal is a 24 VAC output, energized when the
blower is operating during a call for heat.
Connect an accessory 24 VAC, 0.5 amp. maximum humidi-
fier (if used) to the ¼- -in. male quick- -connect HUM termi-
nal and COM- -24V screw terminal on the control board
thermostat strip.
NOTE: If the humidifier has its own 24 VAC power supply, an
isolation relay may be required. Connect the 24 VAC coil of the
isolation relay to the HUM and COM/24V screw terminal on the
control board thermostat strip. See Fig. 37.
3. Communication Connector (communication connection)
This connection is used when the furnace is controlled by
an optional communicating User Interface instead of a stan-
dard thermostat. The communication plug is supplied with
the User Interface. Refer to the instructions supplied with
the User Interface for complete details. See Fig. 36.
4. Outside Air Thermistor (OAT)
The OAT connection is used in conjunction with communi-
cating User Interface. It is not required when the furnace is
controlled by a standard type thermostat. Refer to the in-
structions supplied with the User Interface for complete de-
tails.
Alternate Power Supplies
This furnace is designed to operate on utility generated power
which has a smooth sinusoidal waveform. If the furnace is to be
operated on a generator or other alternate power supply, the
alternate power supply must produce a smooth sinusoidal
waveform for compatibility with the furnace electronics. The
alternate power supply must generate the same voltage, phase, and
frequency (Hz) as shown in Table 9 or the furnace rating plate.
Power from an alternate power supply that is non-sinusoidal may
damage the furnace electronics or cause erratic operation.
Contact the alternate power supply manufacturer for specifications
and details.
37
Hide quick links:
Advertisement
Table of Contents
