Carrier AquaForce B Series Controls, Start-up, Operation, Service And Troubleshooting Instructions

Also see for AquaForce 30XV140: Controls, start-up, operation, service and troubleshooting instructions

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Carrier AquaForce B Series Controls, Start-up, Operation, Service And Troubleshooting Instructions Manual pdf 55 page image

55OPERATIONSequence of OperationWith a command to start the chiller, the evaporator pump willstart. After verifying water flow, the control will monitor theentering and leaving water temperature. If the need for me-chanical cooling is determined, the control decides which cir-cuit and compressor to start. The control will start the requiredcompressor completely unloaded and de-energize the oil sep-arator heater (if already energized). The control will continueto load this circuit by increasing the VFD frequency to satisfycooling requirements. Once fully loaded, the control will startthe second circuit to satisfy load as required. Shutdown of eachcircuit under normal conditions occurs in the opposite se-quence to loading. Once a circuit is fully unloaded the com-pressor is shut off and the EXV will close completely.ACTUATED BALL VALVE (ABV)For chillers equipped with this option (standard in most re-gions), either one or two discharge ABVs are located in the dis-charge line of each circuit of the unit. See Fig. 51 for a typicalABV assembly with enclosure. The ABV is a motorized ballvalve, which is used to close the discharge line to prevent re-frigerant migrating from condenser to the evaporator when thecircuit is off. The valve will be opened before the compressoris started and will normally close when pressure equalizes be-tween suction and discharge lines.The actuated ball valves are linked to the evaporator heater op-eration in the controls. Evaporator Heater option (Main MenuConfiguration MenuFactory ParametersEvaporatorHeater Installed = yes) must be enabled for the actuated ballvalve to operate.See Fig. 52 for a view of a fully open ball valve with the actua-tor removed. The flat surface at the top of the valve shaft isparallel to the discharge line. The ball valve motor mountingplate should be perpendicular to the discharge line at all times.If not, adjust it by loosening the set screw on the side of thevalve, reposition assembly and tighten set screw.See Fig. 53 for a view of the ball valve motor mounting with afully open valve. The motor actuator arm should be at a coun-terclockwise position, with the valve shaft in a parallel posi-tion. If not in a parallel position, loosen the clamping screwand push the disengagement button to rotate the actuator armuntil it stops. Retighten the clamping screw.ABV Manual OperationThe ABV can be operated manually as a discharge servicevalve by completing the following steps:1. Remove the actuator cover.2. With the compressor off hold down the Disengagement(Push) button. See Fig. 53.3. Close the ABV by turning the shaft adapter by hand or witha wrench so that the flats on the end of the shaft are perpen-dicular to the discharge line.4. Release the Push button.5. Disconnect the control power cable to the ABV.Dual Chiller Sequence of OperationWith a command to start the chiller, the master chiller determineswhich chiller will become the lead chiller based on the configura-tion of Lead Lag Select (lead_sel) and Lead/Lag Balance Delta(ll_bal_d). The lead chiller is always started first and the lagchiller is held at zero percent capacity by the master chiller forcingthe lag demand limit value to 0%. If Lead Pulldown Time(lead_pul) has been configured, the lead chiller will continue tooperate alone for that specified time. After the Lead PulldownTime timer has elapsed and when the lead chiller is fully loaded,either all available compression is on or at the master demand lim-it value, then the lag start timer (lstr_tim) is initiated.Fig. 51 — Typical ABV Assembly with EnclosureFig. 52 — Fully Open Ball Valvewith Actuator RemovedFig. 53 — Ball Valve MotorBASE PLATEVALVE MOTORVALVE MOTOR COVERa30-4236VALVE SHAFTa30-4237CLAMPING SCREWACTUATOR ARMDISENGAGEMENTBUTTONMOUNTING - FULLY CLOSEDMOUNTING - FULLY OPENa30-4238