37
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. (30 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.
35.
Thermostats
A single 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. For two stage
thermostat control of the furnace staging, turn SW1-2 ON at the
furnace control board. 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.
35 and 36.
Accessories
(See
Fig.
33 and 35.)
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 humidifier (if
used) to the
¼
--in. male quick--connect HUM terminal 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.
33.
3. Communication Connector (communication connection)
This connection is used when the furnace is controlled by
an optional communicating User Interface instead of a
standard thermostat. The communication plug is supplied
with the User Interface. Refer to the instructions supplied
with the User Interface for complete details. See
Fig.
35.
4. Outside Air Thermistor (OAT)
The OAT connection is used in conjunction with commu-
nicating 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
11 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.
59TP6A