Carrier Air Conditioner Operation And Service Manual

Also see for Air Conditioner: Owner's guide Owner's manual

4Control Module CommunicationRED LED — Proper operation of the control boards can bevisually checked by looking at the red status LEDs (light-emitting diodes). When operating correctly, the red statusLEDs should be blinking in unison at a rate of once every2 seconds. If the red LEDs are not blinking in unison, verifythat correct power is being supplied to all modules. Be sure thatthe Main Base Board (MBB) is supplied with the current soft-ware. If necessary, reload current software. If the problem stillpersists, replace the MBB. A red LED that is lit continuously orblinking at a rate of once per second or faster indicates that theboard should be replaced.GREEN LED — The MBB has one green LED. The LocalEquipment Network (LEN) LED should always be blinkingwhenever power is on. All other boards have a LEN LEDwhich should be blinking whenever power is on. Check LENconnections for potential communication errors at the board J3and/or J4 connectors. Communication between modules is ac-complished by a 3-wire sensor bus. These 3 wires run in paral-lel from module to module. The J4 connector on the MBB pro-vides both power and communication directly to the marqueedisplay only.YELLOW LED — The MBB has one yellow LED. TheCarrier Comfort Network (CCN) LED will blink during timesof network communication.Carrier Comfort Network (CCN) Interface —The 30GTN,R chiller units can be connected to the CCN ifdesired. The communication bus wiring is a shielded,3-conductor cable with drain wire and is supplied and installedin the field. The system elements are connected to the commu-nication bus in a daisy chain arrangement. The positive pin ofeach system element communication connector must be wiredto the positive pins of the system elements on either side of it.This is also required for the negative and signal ground pins ofeach system element. Wiring connections for CCN should bemade at TB3. Consult the CCN Contractor’s Manual for fur-ther information.NOTE: Conductors and drain wire must be 20 AWG (Amer-ican Wire Gage) minimum stranded, tinned copper. Individualconductors must be insulated with PVC, PVC/nylon, vinyl,Teflon, or polyethylene. An aluminum/polyester 100% foilshield and an outer jacket of PVC, PVC/nylon, chrome vinyl,or Teflon with a minimum operating temperature range of–20 C to 60 C is required. Wire manufactured by Alpha (2413or 5463), American (A22503), Belden (8772), or Columbia(02525) meets the above mentioned requirements.It is important when connecting to a CCN communicationbus that a color coding scheme be used for the entire networkto simplify the installation. It is recommended that red be usedfor the signal positive, black for the signal negative, and whitefor the signal ground. Use a similar scheme for cables contain-ing different colored wires.At each system element, the shields of its communicationbus cables must be tied together. If the communication bus isentirely within one building, the resulting continuous shieldmust be connected to a ground at one point only. If the commu-nication bus cable exits from one building and enters another,the shields must be connected to grounds at the lightning sup-pressor in each building where the cable enters or exits thebuilding (one point per building only). To connect the unit tothe network:1. Turn off power to the control box.2. Cut the CCN wire and strip the ends of the red (+), white(ground), and black (–) conductors. (Substitute appropri-ate colors for different colored cables.)3. Connect the red wire to (+) terminal on TB3 of the plug,the white wire to COM terminal, and the black wire to the(–) terminal.4. The RJ14 CCN connector on TB3 can also be used, but isonly intended for temporary connection (for example, alaptop computer running Service Tool).Table 2 — Thermistor DesignationsLEGENDIMPORTANT: A shorted CCN bus cable will preventsome routines from running and may prevent the unitfrom starting. If abnormal conditions occur, unplug theconnector. If conditions return to normal, check theCCN connector and cable. Run new cable if necessary.A short in one section of the bus can cause problemswith all system elements on the bus.THERMISTORNO.PINCONNECTIONPOINT THERMISTOR INPUTT1 J8-13,14 (MBB) Cooler Leaving FluidT2 J8-11,12 (MBB) Cooler Entering FluidT3 J8-21,22 (MBB) Saturated CondensingTemperature, Ckt AT4 J8-15,16 (MBB) Saturated CondensingTemperature, Ckt BT5 J8-24,25 (MBB) Cooler Suction Temperature,Ckt A (EXV Only)T6 J8-18,19 (MBB) Cooler Suction Temperature,Ckt B (EXV Only)T7 J5-11,12 (EXV) Compressor Suction GasTemperature, Ckt A (EXV Only)T8 J5-9,10 (EXV) Compressor Suction GasTemperature, Ckt B (EXV Only)T9J8-7,8 (MBB) Outdoor-Air TemperatureSensor or Dual Chiller LWTSensors (Accessory)T10 J8-5,6 (MBB) Remote Space TemperatureSensor (Accessory)EXV — Electronic Expansion ValveMBB — Main Base Board