Main Base Board (Mbb) - Carrier 48HC 04-28 Controls, Start-Up, Operation And Troubleshooting

Main Base Board (MBB)

See Fig. 32 and Table 29. The MBB is the center of the Com-
fortLink control system. It contains the major portion of the
operating software and controls the operation of the unit. The
MBB continuously monitors input/output channel information
received from its inputs and from the Economizer Control
Board (ECB). The MBB receives inputs from thermistors and
transducers. The MBB also receives the Current Sensor inputs
RED LED - STATUS
J1
J2
J3
J4
J5
J6
J7
GREEN LED -
LEN (LOCAL EQUIPMENT NETWORK)
CEPL130346-01
STATUS
LEN
CCN
Fig. 32 — Main Base Board (MBB)
for compressors and other discrete or digital inputs. The MBB
reads space temperature (SPT) from either a T-55, T-56 or T-58
device and space temperature offset (SPTO) from a T-56 de-
vice. See Field-Installed Accessories section. The MBB con-
trols 11 relays.
NOTE: The Main Base Board (MBB) has a 3-position instance
jumper that is factory set to '1.' Do not change this setting.
YELLOW LED -
CCN (CARRIER COMFORT NETWORK)
INSTANCE JUMPER (SET TO 1)
J8
77
J10
J9
C07026