Carrier AQUASNAP MPW015-045 Operation And Service Manual

Also see for AQUASNAP 30MPA: User manual Installation instructions Controls, start-up, operation, service, and troubleshooting

14CONTROLSGeneral — The 30MP liquid scroll chillers contain theComfortLink™ electronic control system that controls andmonitors all operations of the chiller.The control system is composed of several components aslisted in the sections below. See Fig. 3 for a typical control boxdrawing. See Fig. 4 and 5 for control schematics.Main Base Board (MBB) — See Fig. 6. The MBB isthe heart of the ComfortLink control system. It contains themajor portion of operating software and controls the operationof the machine. The MBB continuously monitors input/outputchannel information received from its inputs and from all othermodules. The MBB receives inputs from the discharge andsuction pressure transducers and thermistors. See Table 15. TheMBB also receives the feedback inputs from each compressorcurrent sensor board and other status switches. See Table 16.The MBB also controls several outputs. Relay outputs con-trolled by the MBB are shown in Table 17. Information istransmitted between modules via a 3-wire communication busor LEN (Local Equipment Network). The CCN (Carrier Com-fort Network) bus is also supported. Connections to both LENand CCN buses are made at the LVT (low voltage terminal).Energy Management Module (EMM) — The EMMmodule is available as a factory-installed option or as a field-installed accessory. The EMM module receives 4 to 20 mAinputs for the leaving fluid temperature reset, cooling set pointand demand limit functions. The EMM module also receivesthe switch inputs for the field-installed 2-stage demand limitand ice done functions. The EMM module communicates thestatus of all inputs with the MBB, and the MBB adjusts thecontrol point, capacity limit, and other functions according tothe inputs received.Current Sensor Board (CSB) — The CSB is used tomonitor the status of the compressors by measuring current andproviding an analog input to the main base board (MBB).Enable/Off/Remote Contact Switch — The Enable/Off/Remote Contact switch is a 3-position switch used tocontrol the chiller. When switched to the Enable position thechiller is under its own control. Move the switch to the Offposition to shut the chiller down. Move the switch to theRemote Contact position and a field-installed dry contact canbe used to start the chiller. The contacts must be capable ofhandling a 24 vac, 50-mA load. In the Enable and RemoteContact (dry contacts closed) positions, the chiller is allowed tooperate and respond to the scheduling configuration, CCNconfiguration and set point data. See Fig. 7.Emergency On/Off Switch — The Emergency On/Offswitch should only be used when it is required to shut thechiller off immediately. Power to the MBB, EMM, andmarquee display is interrupted when this switch is off and alloutputs from these modules will be turned off. See Fig. 7.Board Addresses — The main base board (MBB) has a3-position instance jumper that must be set to ‘1.’ The EMMboard has 4-position DIP switches. All switches are set to ‘On’for all boards except the AUX2 board. The AUX2 board DIPswitch settings are shown on the wiring schematic.Control 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 isaccomplished by a 3-wire sensor bus. These 3 wires run inparallel from module to module. The J4 connector on the MBBprovides both power and communication directly to themarquee display 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 30MP 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. See Table 18. The system elements are connectedto the communication bus in a daisy chain arrangement. Thepositive pin of each system element communication connectormust be wired to the positive pins of the system elements oneither side of it. This is also required for the negative andsignal ground pins of each system element. Wiring connectionsfor CCN should be made at LVT. Consult the CCN Contrac-tor’s Manual for further information.NOTE: Conductors and drain wire must be 20 AWG (Ameri-can 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 lightningsuppressor 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 LVT of the plug,the white wire to COM terminal, and the black wire to the(–) terminal.4. The RJ14 CCN connector on LVT can also be used, but isonly intended for temporary connection (for example, alaptop computer running Service Tool).