• IN VARIABLE FLOW SYSTEMS FLOW IS LIMITED TO A SPECIFIED MAXIMUM RATE FlowCon valves act as flow limiters to assure proper distribution so that one zone does not rob others of needed chilled or hot water. Flow may varied from zero (no flow ) to the rated flow of the valve. Once the pressure differential across the valve exceeds the lower range (e.g., : 22 kPaD in the 22-210 kPa range, 2.2mAq in the 2.2-21.4mAq ), the valve will restrict to limit flow. PROPER DISTRIBUTION PREVENTS CIRCUITS FROM ROBBING ONE ANOTHER PROTECTS PUMPS AGAINST OVER-FLOW ELIMINATES RUN-AWAY FLOW Many designs that utilize variable speed pumps also incorporate two-way automatic temperature control valves to throttle system flow and to save energy. While two-way valves do control flow to some degree, maximum energy savings can be realized with use of automatic flow limiters. Utilizing FCV's in conjunction with two- way valves on a variable - volume hydronic system provides optimum control of flow and assures substantial reduction of horsepower. Figure 1 shows the relationship of the system curve with and without the FlowCon Limiters. Point Q1 is the point of operation without the flow limiter. The FlowCon Flow Limiter automatically limits the flow to the required maximum. Excessive flow requires additional horsepower which is a very expensive waste of energy and money. Figures 2.1 and 2.2 show the working relationship of a two-way control valve and a FlowCon Flow Limiters. Figure 2.1 shows how the two valves work together to maintain design flow shown by the intersection of point B and the pump curve. Below the two-way control valve's full open position, the two-way valve is in control and exhibits a greater pressure drop P1 than the FlowCon Flow Limiter's P2. Additional pressure drop, which would normally increase the flow rate to point A, is absorbed by the FlowCon Flow Limiter (as shown in Figure 2.2 ). The FlowCon FCV takes control by absorbing the additional pressure drop to limit the maximum flow to the design rate.