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2.3 SYSTEM CONTROL <br /> A Main Control Panel (MCP) , in a NEMA 4 enclosure is provided with <br /> indicating lights, timers, integrator, counters and selector switches <br /> for pumps, mixers , and automatic valves for remote operation of the <br /> system. <br /> The pH indicating control loop for the mix chamber Flash/Floc Tank <br /> includes a panel mounted multi function controller indicator with <br /> adjustable set point. The control loop will raise the batch pH using <br /> dilute caustic. The controller output will provide a 4-20 mA signal to <br /> adjust stroke length of the caustic pump and alarm high pH. <br /> The coagulant and polymer dosing rate controlled through a panel <br /> mounted multi-function ratio control station controller will provide a <br /> 4-20 mA signal to adjust stroke length. <br /> Each chemical dosing system day tank includes a separate low level <br /> switch with which to alert the operator but, pump operation will <br /> continue. <br /> A Lamella Settler effluent turbidity sensing loop is provided and will <br /> monitor and alarm on high turbidity. <br /> The system will start processing after manual initiation by the operator <br /> and indication of water flowing in the influent piping by a flow switch <br /> and will continue to run until all water is treated or until a shutdown <br /> alarm point is triggered. <br /> Valve status lights and the status of all electric motors will be <br /> indicated on the MCP. <br /> The flocculator mixer speed will be adjustable from a field mounted <br /> controller in a NEMA 4 enclosure including SPEED POT, START/STOP, and <br /> RUN LIGHT located on the Flash/Floc Tank. <br /> 11654 2-5 <br /> VLS120588 <br />