Outdoor Air Quality Sensor; Space Relative Humidity Sensor Or Humidistat - Carrier 50TC Series Installation Instruction

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 return 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 control 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. 47. Connect the 4- - 20 mA terminal to the
RTU Open controller at J4- - 2 and connect the SIG COM
terminal to the RTU Open controller at J4- - 3. See Fig. 64.
IAQ Sensor
SEN
COM
24 VAC
Fig. 64 - - RTU Open Controller / Indoor CO
(33ZCSPTCO2- - 01 or 33ZCSPTCO2LCD- - 01)
Connections

Outdoor Air Quality Sensor

(P/N 33ZCSPTCO2- - 01 or 33ZCSPTCO2LCD- - 01
plus weatherproof enclosure —
The outdoor air CO sensor is designed to monitor carbon
2
dioxide (CO ) levels in the outside ventilation air and
2
interface with the ventilation damper in an HVAC system.
The OAQ sensor is packaged with an outdoor cover. See
Fig. 49. The outdoor air CO
economizer outside air hood.
Wiring the Outdoor Air CO
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 sensor. See Fig. 49. Connect the 4 to 20 mA
terminal to the RTU Open controller at J4- - 5. Connect the
SIG COM terminal to RTU Open J4- - 6. See Fig. 65.
OAQ Sensor
SEN
COM
24 VAC
Fig. 65 - - RTU Open Controller / Outdoor CO
(33ZCSPTCO2- - 01 or 33ZCSPTCO2LCD- - 01)
Connections
J4-2
J4-3
C08462
Sensor
2
sensor must be located in the
2
Sensor: A dedicated
2
J4-5
J4-6
C11086
Sensor
2
Space Relative Humidity Sensor or Humidistat —
Humidi- - MiZer R System Control Wiring: In units
equipped with the Humidi- - MiZer option there are two loose
wires loose in the control box (one PNK and one PNK/BLK)
used to control the dehumidification function of the unit.
These wires are meant to be tied to a space humidistat or
thermidistat on an electromechanical unit. On RTU Open
controller equipped units these wires must be connected to
J11- - 7 and 8 to allow the Open board to operate the
dehumidification function for the unit. Disconnect the J11
Phoenix style connector from the board and use the plug
screws to secure the wires as follows: secure the PNK/BLK
wires at pin 7 and the PNK wires at pin 8, and then
reconnect the plug to the board at J11.
Relative Humidity Sensors (Space or Duct Mounted):
The accessory space humidity sensor (33ZCSENSRH-02)
or duct humidity sensor (33ZCSENDRH-02) is used to
measure the relative humidity of air within the space or
return air duct. The RH reading is used to control the
Humidi- - MiZer option of the rooftop unit. For wiring
distances up to 500 ft (152 m), use a 3- - conductor, 18 or
20 AWG shielded cable. The shield must be removed
from the sensor end of the cable and grounded at the unit
end. The current loop power for sensor is provided by the
RTU Open controller as 24vdc. Refer to the instructions
supplied with the RH sensor for the electrical
requirements and terminal locations. RTU Open controller
configurations must be changed after adding an RH
sensor. See Fig. 66 and 67 for typical RH sensor wiring.
S J4- - 1 or J4- - 4 = 24vdc loop power
S J4- - 2 or J4- - 5 = 4- - 20mA signal input
NOTE: The factory default for dehumidification control
is normally open humidistat.
MOUNTING
HOLES
Io Gnd
Vin
Vin - J4-1 or J4-4 24Vdc
Io - J4-2 or J4-5 -20mA output
Fig. 66 - - Space Relative Humidity Sensor Typical Wiring
38
WIRING
OPENING
Vo
SW2
C11087