Carrier 48/50AJ specifications Main Control Board MBB Inputs and Outputs, 118

Table 115 — Main Control Board (MBB) Inputs and Outputs

POINT	POINT DESCRIPTION	I/O POINT	PLUG AND PIN	SIGNAL PIN(S)	PORT STATE
NAME		NAME	REFERENCE
INPUTS
GASFAN	YAC Indoor Fan relay (fan request from YAC)	DI1	J6, 3-4	4	0 = 24vac, 1= 0vac
FSD	Fire Shutdown switch input	DI2	J6, 5-6	6	0 = 24vac, 1= 0vac
G	Thermostat ‘G’ input	DI3	J7, 1-2	2	0 = 24vac, 1= 0vac
W2	Thermostat ‘W2’ input	DI4	J7, 3-4	4	0 = 24vac, 1= 0vac
W1	Thermostat ‘W1’ input	DI5	J7, 5-6	6	0 = 24vac, 1= 0vac
Y2	Thermostat ‘Y2’ input	DI6	J7, 7-8	8	0 = 24vac, 1= 0vac
Y1	Thermostat ‘Y1’ input	DI7	J7, 9-10	10	0 = 24vac, 1= 0vac
CSB_A1	Compressor A1 current sensor	DIG1	J9, 10-12	10=5v, 11=Vin, 12=GND	0 = 5vdc, 1 = 0vdc
CSB_A2	Compressor A2 current sensor	DIG2	J9, 7-9	7=5v, 8=Vin, 9=GND	0 = 5vdc, 1 = 0vdc
CSB_B1	Compressor B1 current sensor	DIG3	J9, 4-6	4=5v, 5=Vin, 6 =GND	0 = 5vdc, 1 = 0vdc
CSB_B2	Compressor B2 current sensor	DIG4	J9, 1-3	1=5v, 2=Vin, 3=GND	0 = 5vdc, 1 = 0vdc
DP_A/SCTA	Circuit A saturated	AN1	J8, 21-23	21=5v, 22=Vin, 23=GND	(0-5vdc, thermistor, ohms)
	condensing pressure/temp			(thermistor 21-22)
DP_B/SCTB	Circuit B saturated	AN2	J8, 24-26	24=5v, 25=Vin, 26=GND	(0-5vdc, thermistor, ohms)
	condensing pressure/temp			(thermistor 24-25)
SP_A/SSTA	Circuit A saturated	AN3	J8, 15-17	15=5v, 16=Vin, 17=GND	(0-5vdc, thermistor, ohms)
	suction pressure/temp			(thermistor 15-16)
SP_B/SSTB	Circuit B saturated	AN4	J8, 18-20	18=5v, 19=Vin, 20=GND	(0-5vdc, thermistor, ohms)
	suction pressure/temp			(thermistor 18-20)
RAT	Return air temperature	AN5	J8, 9-10	9	(thermistor, ohms)
SA_TEMP	Supply air temperature	AN6	J8, 11-12	11	(thermistor, ohms)
OAT	Outdoor air temperature	AN7	J8, 13-14	13	(thermistor, ohms)
SPT	Space temperature (T55/56)	AN8	J8, 1-2	1	(thermistor, ohms)
SPTO	Space temperature offset (T56)	AN9	J8, 3-4	3	(thermistor, ohms)
IAQ/IAQMINOV	IAQ analog input	AN10	J8, 5-6	5	(thermistor, ohms)
FLTS	Filter Status	AN11	J8, 7-8	7	(thermistor, ohms)
OUTPUTS
CMPB2	Compressor B2	RLY 1	J10, 20-21	20 = RLY1A (=RLY2A), 21 = RLY1B	1 = Closes RLY1A/RLY1B
CMPB1	Compressor B1	RLY 2	J10, 22-23	22 = RLY2A (=RLY1A), 23 = RLY2B	1 = Closes RLY2A/RLY2B
CMPA2	Compressor A2	RLY 3	J10, 24-25	24 = RLY3A (=RLY4A), 25 = RLY3B	1 = Closes RLY3A/RLY3B
CMPA1	Compressor A1	RLY 4	J10, 26-27	26 = RLY4A (=RLY3A), 27 = RLY4B	1 = Closes RLY4A/RLY4B
CONDFANB	Condenser fan B	RLY 5	J10, 10-11	10 = RLY5A (=RLY6A), 11 = RLY5B	1 = Closes RLY5A/RLY5B
CONDFANA	Condenser fan A	RLY 6	J10, 12-13	12 = RLY6A (=RLY5A), 13 = RLY6B	1 = Closes RLY6A/RLY6B
HS2	Heat stage 2	RLY7	J10, 14-16	14 = 15 = RLY7A, 16 = RLY7B	1 = Closes RLY7A/RLY7B
HS1	Heat stage 1	RLY 8	J10, 17-19	17 = 18 = RLY8A, 19 = RLY8B	1 = Closes RLY8A/RLY8B
HIR	Heat interlock relay	RLY 9	J10, 4-6	4 = 5 = RLY9A, 6 = RLY9B	1 = Closes RLY9A/RLY9B
SF	Supply fan	RLY 10	J10, 7-9	7 = 8 = RLY10A, 9 = RLY10B	1 = Closes RLY10A/RLY10B
ALRM	Alarm output relay	RLY 11	J10, 1-3	1 = 2 = RLY11A, 3 = RLY11B	1 = Closes RLY11A/RLY11B

YAC — Gas Heat Unit

RED LED - STATUS	GREEN LED-	YELLOW LED -
	LEN (LOCAL EQUIPMENT NETWORK)	CCN (CARRIER COMFORT NETWORK)

				INSTANCE JUMPER (SET TO 1)
		CEPL130346-01 HK 50AA029 CE BO 430346
J1	J2		STATUS
J4	J3	LEN		J10
	J5
J6
			A48-7811
		J7	J8	J9

Fig. 26 — Main Base Board (MBB)

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