Carrier 50TCQD Installation Instructions Manual page 31

The raceway provides the UL required clearance between
high- - and low- - voltage wiring. Pass the control wires
through the hole provided in the corner post, then feed the
wires thorough the raceway to the RTU- - MP. Connect to
the wires to the removable Phoenix connectors and then
reconnect the connectors to the board.
Space Temperature (SPT) Sensors
A field- - supplied Carrier space temperature sensor is
required with the RTU- - MP to monitor space temperature.
There are 3 sensors available for this application:
S 33ZCT55SPT, space temperature sensor with override
button
S 33ZCT56SPT, space temperature sensor with override
button and setpoint adjustment
S 33ZCT59SPT, space temperature sensor with LCD
(liquid crystal display) screen, override button, and
setpoint adjustment
Use 20 gauge wire to connect the sensor to the controller.
The wire is suitable for distances of up to 500 ft. Use a
three- - conductor shielded cable for the sensor and setpoint
adjustment connections. If the setpoint adjustment
(slidebar) is not required, then an unshielded, 18 or 20
gauge, two- - conductor, twisted pair cable may be used.
Connect T- - 55 - - See Fig. 30 for typical T- - 55 internal
connections. Connect the T- - 55 SEN terminals to
RTU- - MP J20- - 1 and J20- - 2. See Fig. 49.
SEN
SEN
Fig. 49 - - RTU- - MP T- - 55 Sensor Connections
Connect T- - 56 - - See Fig. 32 for T- - 56 internal
connections. Install a jumper between SEN and SET
terminals as illustrated. Connect T- - 56 terminals to
RTU- - MP J20- - 1, J20- - 2 and J20- - 3 per Fig. 50.
SEN
SEN
Jumper
SET
SET
Fig. 50 - - RTU- - MP T- - 56 Sensor Connections
Connect T- - 59 - - The T- - 59 space sensor requires a
separate, isolated power supply of 24 VAC. See Fig. 51
for internal connections at the T- - 59. Connect the SEN
terminal (BLU) to RTU- - MP J20- - 1. Connect the COM
terminal (BRN) to J20- - 2. Connect the SET terminal (STO
or BLK) to J20- - 3.
J20-1
J20-2
C08460
J20-1
J20-2
J20-3
C08461
BRN (COM)
BLK (STO)
BLU (SPT)
OR SET SEN
OPB COM- PWR+
NOTE: Must use a separate isolated transformer.
Fig. 51 - - Space Temperature Sensor Typical Wiring
(33ZCT59SPT)
Economizer controls —
Outdoor Air Enthalpy Control (PNO 33CSENTHSW) - -
The enthalpy control (33CSENTHSW) is available as a
field- - installed accessory to be used with the EconoMi$er2
damper system. The outdoor air enthalpy sensor is part of
the enthalpy control. (The separate field- - installed
accessory return air enthalpy sensor (33CSENTSEN) is
required for differential enthalpy control. See Fig. 35.)
Locate the enthalpy control in the economizer next to the
Actuator Motor. Locate two GRA leads in the factory
harness and connect the gray lead labeled "ESL" to the
terminal labeled "LOW". See Fig. 35. Connect the
enthalpy control power input terminals to economizer
actuator power leads RED (connect to 24V) and BLK
(connect to GND).
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 above. Add and install a
return air enthalpy sensor.
To wire the return air enthalpy sensor, perform the
following:
1. Use a 2- - conductor, 18 or 20 AWG, twisted pair cable
to connect the return air enthalpy sensor to the enthal-
py 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
31
SENSOR
WIRING
POWER
WIRING
24 VAC
C07132
)
2