ZONEBB3Z(AC/HP)01: Quick Reference Guide
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3
Fig. 3 – Wiring Diagram for Installation of Thermostats
A210050
Fig. 4 – Installing Dampers
Step 4 – Install Barometric Bypass Damper
The barometric bypass damper is a critical part of Bryant 3-Zone System
for controlling noise at minimum airflow. A barometric bypass should be
installed unless the duct work and indoor unit have been sized for use
without a bypass. When a direct bypass (outlet air fed back directly into
the return) is used, bypassing decreases entering air temperature in
cooling and increases it in heating. Excessive bypassing will lead to limit
trips, either through the LAT/HPT sensor or the equipment internal
limits.
Step 5 – Install Leaving Air Temperature (LAT) Sensor
/ Heat Pump Temperature (HPT) Sensor (optional)
The Leaving Air Temperature (LAT) sensor is used to detect a cooling
overload condition and is connected to the LAT and LATC terminals.
Polarity does not matter. Locate LAT sensor in main supply trunk after
heating and cooling coil and before bypass damper and first branch.
Cycling on internal equipment limits is to be avoided because it over
stresses and can shorten the life of the equipment. The LAT limit setting
should be selected to trip below the equipment limit.
Fig. 5 – Leaving Air Temperature (LAT) Sensor / Heat Pump
Temperature (TPT) Sensor optional
The HPT sensor is used with ZONEBB3ZHP01 to detect a cooling
overload condition and is connected to the HPT and HPTC terminals.
The HPT sensor will also be monitored in heating to detect a heating
overload condition at the coil with a shutdown temperature of 115°F. It
can be installed through the wall of the fan coil or may be located
entirely inside the fan coil near the blower inlet being careful that it does
not interfere with the blower wheel. If the HPT sensor is not used, the
10K ohm resistor attached to the 2 HPT terminals on the board must be
left in place.
A210068
Zone 1
Thermostate Wiring
Example
A210068
Zone 2
A210067
