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103
Table 102—MBB Connections
DISPLAY NAME
POINT DESCRIPTION
SENSOR LOCATION
TYPE OF I/O
CONNECTION
PIN NUMBER
INPUTS
INPUTS
Input power from TRAN1
control box
24 VAC
J1, 1-3
HUM
Indoor fan output feedback (IGC), or
Space humidity switch
gas section
space
switch input
J6, 4
FDWN
Fire shutdown switch
supply/return/space
switch input
J6, 5-6
G
Thermostat G (Fan)
space
switch input
J7, 2
W2
Thermostat W2 (2nd Stage Heat)
space
switch input
J7, 4
W1
Thermostat W1 (1st Stage Heat)
space
switch input
J7, 6
Y2
Thermostat Y2 (2nd Stage Cool)
space
switch input
J7, 8
Y1
Thermostat Y1 (1st Stage Cool)
space
switch input
J7, 10
SPT
Space temperature (T55/56)
space
10k thermistor
J8, 1-2
SPTO or
RAT
Space temperature offset (T56), or
Return air temperature
space
return
10k thermistor
J8, 2-3
OAT
Outdoor air temperature
outdoor coil support
10k thermistor
J8, 5-6
SAT
Supply air temperature
indoor fan housing, or supply duct
10k thermistor
J8, 7-8
SCT.A
Saturated condenser temperature, circuit A
outdoor coil, circuit A
5k thermistor
J8, 9-10
SCT.B
Saturated condenser temperature, circuit B
outdoor coil, circuit B
5k thermistor
J8, 11-12
SCT.C
Saturated condenser temperature, circuit C
outdoor coil, circuit C
5k thermistor
J8, 13-14
FAN.S
Fan status switch
indoor fan section
switch input
J8, 15-16
SSP.A
Suction pressure, circuit A
compressor A suction
analog input
J8, 18-20
SSP.B
Suction pressure, circuit B
compressor B suction
analog input
J8, 21-23
SSP.C
Suction pressure, circuit C
compressor C suction
analog input
J8, 24-26
FIL.S
Filter status switch
indoor fan section
switch input
J9, 2-3
CS.A1
Compressor A1 feedback
control box
digital input
J9, 4-6
CS.B1 or
CS.A2
Compressor B1 feedback, or
Compressor A2 feedback
control box
digital input
J9, 7-9
CS.C1 or
CS.B1
Compressor C1 feedback, or
Compressor B1 feedback
control box
digital input
J9, 10-12
OUTPUTS
OUTPUTS
Output power to ECB
24 VAC
J2, 1-2
Output power to Marquee Display
24 VAC
J4, 5-6
CRC
Cool-Reheat1 control
relay
J10, 3
CMP.C or
OFC.2
Compressor C1 relay, or
Outdoor fan 2 relay
relay
J10, 6
CMP.B
Compressor B1 relay
relay
J10, 9
CMP.A
Compressor A1 relay
relay
J10, 11
CCH or
OFC.3 or
OFC.1
Crankcase heat relay, or
Outdoor fan 3 relay, or
Outdoor fan 1 relay
relay
J10, 13
OFC.2 or
RH2.B
Outdoor fan 2 relay, or
Reheat2 valve, circuit B and C
relay
J10, 16
OFC.1 or
RH2.A
Outdoor fan 1 relay, or
Reheat2 valve, circuit A
relay
J10, 19
IDF
Indoor fan relay
relay
J10, 21
ALRM
Alarm relay
relay
J10, 23
HT.1
Heat stage 1 relay
relay
J10, 25
HT.2
Heat stage 2 relay
relay
J10, 27
COMMUNICATION
COMMUNICATION
Local Equipment Network (LEN)
communication
J5, 1-3
Carrier Comfort Network (CCN)
communication
J5, 5-7
Network device power
24 VAC
J5, 9-10
48/
50P
G
C
03
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