4
Step 4 — Install Barometric Bypass Damper
The barometric bypass damper is a critical part of Carrier 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 ZONECC3ZHP01 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.
NOTE
: ZONECC3ZAC01 model
does not have HPT connector.
Fig. 6 -- Leaving Air Temperature (LAT) Sensor
Please refer to
Limit Temperature Levels and Actions Table
in
the Installation and Start--Up Instructions for additional
information on the response of the system to LAT/HPT sensors.
Step 6 — Connect the Power Supply
Optional:
Use a dedicated 24 VAC, 40 VA, 60 Hz isolated
transformer (not included).
Otherwise, if the cooling and heating systems have separate
transformers, twist off the
Rc/Rh
jumper using a pair of long nosed
pliers. Then connect the R of the cooling transformer to Rc, the R
of the heating transformer to Rh and the common of both
transformers to C. Connect a jumper wire between Rz and Rc. Rc
powers G,Y, and O outputs. Rh power W outputs.
Fig. 7 -- Connecting the Power Supply
Step 7 — Wire the HVAC Equipment
The descriptions below and Table 1 will help you choose the
connect wiring diagram for your system. Table 1 also shows the
proper setting of dipswitches 9 and 10 for each diagram.
There are 8 dipswitch settings on the AC zone control and an
additional 4 dipswitch on the HP zone controls board. Table 1
summarizes their function and available settings.
Fig. 8 -- Dip Switches
