Bryant 987MB, Installation, Start-Up, Operating And Service And Maintenance Instructions

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987MB: Installation, Start-up, Operating and Service and Maintenance Instructions
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
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A11157
Fig. 38 – Field-supplied Isolation Relay for Humidifiers with Internal Power Supply
Accessories
(See Fig. 37 and Fig. 38 .)
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. 38 .
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. 37 .
4. Outside Air Thermistor (OAT)
The OAT connection is used in conjunction with communicating
User Interface. It is not required when the furnace is controlled by a
standard type thermostat. Refer to the instructions supplied with the
User Interface for complete details.
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.