Alternate Power Supplies; Electrical Data - Bryant 987MA Installation, Start-Up, Operating And Service And Maintenance Instructions

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. 32.)
3. Communication Connector (ABCD connection)
This connection is used when the furnace is controlled by
an optional communicating User Interface instead of a
standard thermostat. The ABCD plug is supplied with the
User Interface. Refer to the instructions supplied with the
User Interface for complete details. See Fig. 34.
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.
UNIT SIZE VOLTS---
HERTZ---
PHASE
60,000 115--- 60--- 1
80,000 115--- 60--- 1
100,000 115--- 60--- 1
120,000 115--- 60--- 1
* Permissible limits of the voltage range at which the unit operates satisfactorily.
# Unit ampacity = 125 percent of largest operating component's full load amps plus 100 percent of all other potential operating components' (EAC, humidifier,
etc.) full load amps.
Time ---delay type is recommended.
{
Length shown is as measured one way along wire path between furnace and service panel for maximum 2 percent voltage drop.
}
Table 9 – Electrical Data
MODULATING
OPERATING VOLTAGE MAXIMUM
RANGE* UNIT
AMPS
Maximum* Minimum*
127 104
127 104
127 104 14.8
127 104 14.8

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.
UNIT MINIMUM
AMPACITY#
9.7 12.7
9.7 12.7
19.1
19.1
32
MAXIMUM MAXIMUM
WIRE WIRE FUSE OR CKT
SIZE LENGTH BKR
AWG FT (M)} AMPS{
14 29 (8.8)
14 29 (8.8)
12 30 (9.1)
12 30 (9.1)
15
15
20
20