Bryant 551J - Manual (Page 24)

24
SEN J20-1
J20-2 SEN
SET
Jumper
J20-3 SET
C08461
Fig. 43 -- 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. 44
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.
OR SET SEN
OPB COM- PWR+
BLU (SPT)
BLK (STO)
24 VAC
SENSOR
WIRING
POWER
WIRING
BRN (COM)
NOTE: Must use a separate isolated transformer.
C07132
Fig. 44 -- 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. 45.)
7
ESL
CTB
ECON
LOW
GND
24V
Enthalpy
Switch
GRA
BLK
RED
Factory Wiring Harness
ECONO
MOTOR
C09026
Fig. 45 -- Enthalpy Switch (33CSENTHSW) Connections
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. 45. 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.
Return Air Enthalpy Sensor — Mount the return--air
enthalpy sensor (33CSENTSEN) in the return--air section
of the economizer. The return air sensor is wired to the
enthalpy controller (33CSENTHSW). See Fig. 46.
ESL
LOW
GND
24V
GRA
BLK
RED
ECONO
MOTOR
– 4-20
Main
+ VDC
Out
– 4-20 Main
Out
+ 24-36
VDC In
C09027
Fig. 46 -- 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, twisted pair cable
to connect the return air enthalpy 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
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 return duct, with and without LCD
display, and in combination with space temperature
sensors. Sensors use infrared technology 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
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