Bryant 551J installation instructions RTU-MP T-56 Sensor Connections

		SEN			J20-1
		SEN
					J20-2
		SET		Jumper
		SET
					J20-3
						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
551J		terminal (BRN) to J20-2. Connect the SET terminal (STO
	j or BLK) to J20-3.
			BRN (COM)

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.

	BLK (STO)	SENSOR
	BLU (SPT)	WIRING
OR SET	SEN
OPB	COM- PWR+

	POWER
24 VAC	WIRING

NOTE: Must use a separate isolated transformer.

– 4-20	24V	RED
Main	GND	BLK
+ VDC
Out	LOW	GRA

+24-36 VDC In

–4-20 Main Out

ECONO

MOTOR

ESL

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.)

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

Enthalpy
Switch
24V	RED
GND	BLK
LOW	GRA	ESL

7

ECONO MOTOR

CTB

ECON

controller.

Indoor Air Quality (CO2 sensor) — The indoor air quality sensor accessory monitors space carbon dioxide (CO2) 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 CO2 present in the space air.

The CO2 sensors are all factory set for a range of 0 to

Factory Wiring Harness

C09026

Fig. 45 - Enthalpy Switch (33CSENTHSW) Connections

2000 ppm and a linear mA output of 4 to 20. Refer to the instructions supplied with the CO2 sensor for electrical

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