Carrier 48HC 04-28 Controls, Start-up, Operation And Troubleshooting

Also see for /50HC 04-28: Manual

Contents

Carrier 48HC 04-28 Controls, Start-up, Operation And Troubleshooting Manual pdf 77 page image

77Main 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 theoperating software and controls the operation of the unit. TheMBB continuously monitors input/output channel informationreceived from its inputs and from the Economizer ControlBoard (ECB). The MBB receives inputs from thermistors andtransducers. The MBB also receives the Current Sensor inputsfor compressors and other discrete or digital inputs. The MBBreads space temperature (SPT) from either a T-55, T-56 or T-58device 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 instancejumper that is factory set to ‘1.’ Do not change this setting.Fig. 32 — Main Base Board (MBB)CEPL130346-01STATUSLENJ1 J2J4 J3J5J6J7 J8 J9J10CCNRED LED - STATUS GREEN LED -LEN (LOCAL EQUIPMENT NETWORK) YELLOW LED -CCN (CARRIER COMFORT NETWORK)INSTANCE JUMPER (SET TO 1)C07026