Bryant 551J RTU-MP Controller Inputs and Outputs, Type of I/O Connection PIN Name Numbers Inputs

551J

Table 3 – RTU-MP Controller Inputs and Outputs

			POINT NAME	BACnet OBJECT	TYPE OF I/O	CONNECTION PIN
				NAME		NUMBERS
				INPUTS
	Space Temperature Sensor			sptsens	AI (10K Thermistor)	J20---1, 2
	Supply Air Temperature			sat	AI (10K Thermistor)	J2---1, 2
	Local Outside Air Temperature Sensor			oatsens	AI (10K Thermistor)	J2---3, 4
	Space Temperature Offset Pot			sptopot	AI (100K Potentiometer)	J20---3
	Indoor Air Quality			iaq	AI (4---20 ma)	J4---2, 3
	Outdoor Air Quality			oaq	AI (4---20 ma)	J4---5, 6
	Safety Chain Feedback			safety	DI (24 VAC)	J1---9
	Compressor Safety			compstat	DI (24 VAC)	J1---2
	Fire Shutdown			firedown	DI (24 VAC)	J1---10
	Enthalpy Switch			enthalpy	DI (24 VAC)	J2---6, 7
j	Humidistat Input Status			humstat	DI (24 VAC)	J5---7, 8
				CONFIGURABLE INPUTS*
	Space Relative Humidity			sprh	AI (4---20 ma)	J4---2,3 or J4---5,6
	Outside Air Relative Humidity			oarh	AI (4---20 ma)
	Supply Fan Status			fanstat	DI (24 VAC)	J5---1,2 or J5---3,4 or
	Filter Status			filtstat	DI (24 VAC)
						J5 5,6 or J5---7,8
	Remote Occupancy Input			remocc	DI (24 VAC)
				OUTPUTS
	Economizer Commanded Position			econocmd	4---20ma	J2---5
	Supply Fan Relay State			sf	DO Relay (24VAC , 1A)	J1---4
	Compressor 1 Relay State			comp_1	DO Relay (24VAC , 1A)	J1---8
	Compressor 2 Relay State			comp_2	DO Relay (24VAC , 1A)	J1---7
	Heat Stage 1 Relay State			heat_1	DO Relay (24VAC , 1A)	J1---6
	Heat Stage 2 Relay State			heat_2	DO Relay (24VAC , 1A)	J1---5
	Power Exhaust Relay State			aux_2	DO Relay (24VAC , 1A)	J11---3
	Dehumidification Relay State			humizer	DO Relay (24VAC, 1A)	J11---7, 8
	LEGEND
	AI	---	Analog Input
	AO ---		Analog Output
	DI	---	Discrete Input
	DO ---		Discrete Output

*These inputs (if installed) take the place of the default input on the specific channel according to schematic. Parallel pins J5--- 1 = J2--- 6, J5--- 3 = J1--- 10, J5--- 5 = J1--- 2 are used for field--- installation.

The RTU-MP controller requires the use of a Byrant space sensor. A standard thermostat cannot be used with the RTU-MP system.

Supply Air Temperature (SAT) Sensor - On FIOP-equipped 551J unit, the unit is supplied with a supply-air temperature (SAT) sensor (33ZCSENSAT). This sensor is a tubular probe type, approx 6-inches (12.7 mm) in length. It is a nominal 10-k ohm thermistor.

The SAT is factory-wired. The SAT probe is wire-tied to the supply-air opening (on the horizontal opening end) in its shipping position. Remove the sensor for installation. Re-position the sensor in the flange of the supply-air opening or in the supply air duct (as required by local codes). Drill or punch a 1/2-in. hole in the flange or duct. Use two field-supplied, self-drilling screws to secure the

SUPPLY AIR TEMPERATURE

SENSOR

SUPPLY AIR

ROOF CURB

RETURN AIR

C08200

sensor probe in a horizontal orientation. See Fig. 39.

Fig. 39 - Typical Mounting Location for Supply Air Temperature (SAT) Sensor on Small Rooftop Units

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