Carrier WeatherMaker 48TC 04, Installation Instructions Manual

Page: 44 / 60

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If the 48TC unit has an economizer system and
free-cooling operation is required, a sensor representing Return
Air Temperature must also be connected (field-supplied and in-
stalled). This sensor may be a T-55 Space Sensor (see Fig. 48)
installed in the space or in the return duct, or it may be sensor
PNO 33ZCSENSAT, installed in the return duct. Connect this
sensor to TB1-1 and TB1-3 per Fig. 49.
Configure the Unit for Thermostat Mode — Connect to the
CCN bus using a CCN service tool and navigate to Premier-
Link Configuration screen for Operating Mode. Default setting
is Sensor Mode (value 1). Change the value to 0 to reconfigure
the controller for Thermostat Mode.
When the PremierLink is configured for Thermostat Mode,
these functions are not available: Fire Shutdown (FSD), Re-
mote Occupied (RMTOCC), Compressor Safety (CMPSAFE),
Supply Fan Status (SFS), and Filter Pressure Switch (FILTER).
ECONOMIZER CONTROLS
Indoor Air Quality (CO
2
) Sensor — The indoor air quality
sensor accessory monitors space carbon dioxide (CO
2
) levels.
This information is used to monitor IAQ levels. Several types
of sensors are available, for wall mounting in the space or in re-
turn duct, with and without LCD display, and in combination
with space temperature sensors. Sensors use infrared technolo-
gy to measure the levels of CO
2
present in the space air.
The CO
2
sensors are all factory set for a range of 0 to 2000
ppm and a linear mA output of 4 to 20. Refer to the instructions
supplied with the CO
2
sensor for electrical requirements and
terminal locations. See Fig. 53 for typical CO
2
sensor wiring
schematic.
Fig. 53 — Indoor/Outdoor Air Quality (CO
2
) Sensor
(33ZCSENCO2) — Typical Wiring Diagram
To accurately monitor the quality of the air in the condi-
tioned air space, locate the sensor near a return-air grille (if
present) so it senses the concentration of CO
2
leaving the
space. The sensor should be mounted in a location to avoid di-
rect breath contact.
Do not mount the IAQ sensor in drafty areas such as near
supply ducts, open windows, fans, or over heat sources. Allow
at least 3 ft (0.9 m) between the sensor and any corner. Avoid
mounting the sensor where it is influenced by the supply air;
the sensor gives inaccurate readings if the supply air is blown
directly onto the sensor or if the supply air does not have a
chance to mix with the room air before it is drawn into the re-
turn airstream.
Wiring the Indoor Air Quality Sensor — For each sensor, use
two 2-conductor 18 AWG (American Wire Gage) twisted-pair
cables (unshielded) to connect the separate isolated 24 vac
power source to the sensor and to connect the sensor to the con-
trol board terminals.
To connect the sensor to the control, identify the positive (4
to 20 mA) and ground (SIG COM) terminals on the sensor. See
Fig. 48. Connect the 4-20 mA terminal to terminal TB1-9 and
connect the SIG COM terminal to terminal TB1-11. See
Fig. 54.
Fig. 54 — Indoor CO
2
Sensor (33ZCSENCO2)
Connections
Refer to PremierLink Installation, Start-up, and Config-
uration Instructions, for detailed configuration information.
Outdoor Air Quality Sensor (P/N: 33ZCSENCO
2
Plus
Weatherproof Enclosure) — The outdoor air CO
2
sensor is
designed to monitor carbon dioxide (CO
2
) levels in the outside
ventilation air and interface with the ventilation damper in an
HVAC system. The OAQ sensor is packaged with an outdoor
cover. See Fig. 55. The outdoor air CO
2
sensor must be located
in the economizer outside air hood.
Fig. 55 — Outdoor Air Quality Sensor Cover
Wiring the Outdoor Air CO
2
Sensor — A dedicated power
supply is required for this sensor. A two-wire cable is required
to wire the dedicated power supply for the sensor. The two
wires should be connected to the power supply and terminals 1
and 2.
To connect the sensor to the control, identify the positive (4
to 20 mA) and ground (SIG COM) terminals on the OAQ sen-
sor. See Fig. 48. Connect the 4 to 20 mA terminal to the TB1-
13 terminal of the 48TC unit. Connect the SIG COM terminal
to the TB1-11 terminal of the 48TC unit. See Fig. 56.
Fig. 56 — Outdoor CO
2
Sensor Connections
8 7 6 5 4 3 2 1 2 1
H G 24 VAC
OR
24 VDC
NC
ALARM
RELAY
CONTACT
S
COM
NO
}
0-10VDC
S IG COM
4-20mA
+
+
-
+ -
J 3 J4
S EN J5-5
J5- 3 COM
9
11
TB1
TB1
IAQ S en s or
PL
24 VAC
COVER REMOVED S IDE VIEW
S EN J5-2
J5- 3 COM
1 3
11
TB1
TB1 PL
OAQ S en s or/RH S en s or
24 VAC