Carrier 50TC*D17 Series Installation Instructions Manual page 22

The outdoor enthalpy changeover setpoint is set at the
enthalpy controller.
Differential Enthalpy Control — Differential enthalpy
control is provided by sensing and comparing the outside
air and return air enthalpy conditions. Install the outdoor
air enthalpy control as described on page 21. Add and
install a return air enthalpy sensor.
24V
– 4-20
Main
GND
+ VDC
Out
LOW
+ 24-36
VDC In
– 4-20 Main
Out
Fig. 33 - - Outside and Return Air Enthalpy Sensor
Wiring
To wire the return air enthalpy sensor, perform the
following:
1. Use a 2- - conductor, 18 or 20 AWG (American Wire
Gage), twisted pair cable to connect the return air en-
thalpy sensor to the enthalpy controller.
2. Connect the field- - supplied RED wire to (+) spade
connector on the return air enthalpy sensor and the
(+) terminal on the enthalpy controller. Connect the
BLK wire to (- - ) spade connector on the return air en-
thalpy sensor and the (- - ) terminal on the enthalpy
controller.
Indoor Air Quality (CO sensor) — The indoor air quality
2
sensor accessory monitors space carbon dioxide (CO
levels. This information is used to monitor IAQ levels.
Several types of sensors are available, for wall mounting
in the space or in return duct, with and without LCD
display, and in combination with space temperature
sensors. Sensors use infrared technology to measure the
levels of CO present in the space air.
2
The CO sensors are all factory set for a range of 0 to
2
2000 ppm and a linear mA output of 4 to 20. Refer to the
instructions supplied with the CO
requirements and terminal locations. See Fig. 34 for
typical CO sensor wiring schematic.
2
To accurately monitor the quality of the air in the
conditioned air space, locate the sensor near a return- - air
grille (if present) so it senses the concentration of CO
leaving the space. The sensor should be mounted in a
location to avoid direct breath contact.
RED
ECONO
MOTOR
BLK
GRA
ESL
C09027
)
2
sensor for electrical
2
2
H G 24 VAC
OR
+ -
24 VDC
2 1 8 7 6 5 4 3 2 1
J3 J4
Fig. 34 - - Indoor/Outdoor Air Quality (CO
(33ZCSENCO2) - - Typical Wiring Diagram
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. 34. Connect the 4- - 20 mA terminal to
terminal TB1- - 9 and connect the SIG COM terminal to
terminal TB1- - 11. See Fig. 35.
IAQ Sensor
SEN
COM
24 VAC
Fig. 35 - - Indoor CO
Connections
Refer to Form 33CS- - 58SI, PremierLink Installation,
Start- - up, and Configuration Instructions, for detailed
configuration information.
22
+ 0-10VDC
-
SIG COM
+
4-20mA
NC } ALARM
COM RELAY
NO CONTACTS
C08635
) Sensor
2
TB1
9 J5-5
TB1
11 J5-3
C08636
Sensor (33ZCSENCO2)
2
PL