Supply Air Temperature Sensor; Indoor Air Quality Sensor; Humidity Sensor (Wall-Mounted); Connect The Outputs - Carrier 42C Installation And Start-Up Instructions Manual

SUPPLY AIR TEMPERATURE (SAT) SENSOR INSTAL-
LATION — On fan coil units with heating or cooling, the SAT
sensor is factory-installed. The SAT is factory-installed in the
fan coil air outlet. No installation is required. The part number
is HH79NZ005.
INDOOR AIR QUALITY SENSOR INSTALLATION
(Monitor Only) — The indoor air quality (IAQ) sensor acces-
sory monitors carbon dioxide levels. This information is used
to monitor IAQ levels. Three types of sensors are provided.
The wall sensor can be used to monitor the conditioned air
space. Sensors use infrared technology to measure the levels of
CO present in the air. The wall sensor is available with or
2
without an LCD readout to display the CO
Fig. 12.
Sensor accessory descriptions and part numbers are shown
in Table 2. To mount the sensor, refer to the installation instruc-
tions shipped with the accessory kit.
Table 2 — CO Sensor Accessories
2
CO SENSOR
2
ACCESSORY
PART NUMBERS
33ZCSENCO2 Wall Mount Sensor (with display)
Wall Mount Sensor with
33ZCT55CO2 33ZCT55SPT space temperature
sensor (no display)
Wall Mount Sensor with
33ZCT56SPT space temperature
33ZCT56CO2
sensor and set point adjustment (no
display)
The CO sensors listed in Table 2 are all factory set for a
2
range of 0 to 2000 ppm and a linear voltage output of 0 to
10 vdc. Refer to the instructions supplied with the CO
for electrical requirements and terminal locations.
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
space. The sensor should be mounted in a location to avoid
direct 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 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
air-stream.
Indoor Air Quality Sensor Wiring — To wire the sensors
after they are mounted in the conditioned air space or outdoor
location, see Fig. 13 and the instructions shipped with the sen-
sors. For each sensor, use two 2-conductor 18 AWG 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 board,
identify the positive (0-10 VDC) and ground (SIG COM) ter-
minals on the sensor. Connect the 1-10 VDC terminal to termi-
nal IAQ and connect the SIG COM terminal to terminal GND.
HUMIDITY SENSOR
TION — The accessory space humidity sensor is installed on
an interior wall to measure the relative humidity of the air with-
in the occupied space. See Fig. 14.
The use of a standard 2- x 4-in. electrical box to accommo-
date the wiring is recommended for installation. The sensor can
be mounted directly on the wall, if acceptable by local codes.
If the sensor is installed directly on a wall surface, install the
humidity sensor using 2 screws and 2 hollow wall anchors
(field-supplied); do not overtighten screws. See Fig. 8.
level in ppm. See
2
DESCRIPTION
sensor
2
leaving the
2
(Wall-Mounted) INSTALLA-
Do NOT clean or touch the sensing element with chemical
solvents; they can permanently damage the sensor.
The sensor must be mounted vertically on the wall. The
Carrier logo should be oriented correctly when the sensor is
properly mounted.
DO NOT mount the sensor in drafty areas such as near heat-
ing or air-conditioning ducts, open windows, fans, or over heat
sources such as baseboard heaters, radiators, or wall-mounted
light dimmers. Sensors mounted in those areas will produce
inaccurate readings.
Avoid corner locations. Allow at least 4 ft between the sen-
sor and any corner. Airflow near corners tends to be reduced,
resulting in erratic sensor readings.
Sensor should be vertically mounted approximately 5 ft up
from the floor, beside the space temperature sensor.
For distances up to 500 feet, use a 3-conductor, 18 or
20 AWG cable. A CCN communication cable can be used,
although the shield is not required. The shield must be removed
from the sensor end of the cable if this cable is used. See
Fig. 15 for wiring details.
The power for the sensor is provided by the control board.
The board provides 24 vdc for the sensor. No additional power
source is required.
To wire the sensor, perform the following:
1. At the sensor, remove 4-in. of jacket from the cable. Strip
1
/ -in. of insulation from each conductor. Route the cable
4
through the wire clearance opening in the center of the
sensor.
2. Connect the RED wire to the sensor screw terminal
marked (+).
3. Install one lead from the resistor (supplied with the sen-
sor) and the WHITE wire, into the sensor screw terminal
marked (–). After tightening the screw terminal, test the
connection by pulling gently on the resistor lead.
4. Connect the remaining lead from the resistor to the
BLACK wire and secure using a closed end type crimp
connector or wire nut.
5. Using electrical tape, insulate any exposed resistor lead to
prevent shorting.
6. At the control box, remove the jacket from the cable and
route the RED conductor over to the left side of the con-
trol board. Route the remaining conductors to the right
side of the control board.
1
7. Strip / -in. of insulation from each conductor and equip
4
1
each with a / -in. female quick connect terminal.
4
8. Connect the RED wire to terminal 24VDC on the control
board.
NOTE: The 24VDC terminal is used for RH sensor
wiring only.
9. Connect the BLACK wire to terminal GND on the con-
trol board.
10. Connect the WHITE/CLEAR wire to terminal RH on the
control board.
11. Connect shield to ground (if shielded wire is used).
Connect the Outputs —
outputs (fan, staged heat, valves) as shown in the applicable
typical wiring diagrams in Fig. 2 and 3. Please refer to fan coil
unit schematic for full wiring details.
10
Wire the fan coil controller's