Many times, you want the flexibility of adjusting the flow (L/sec) through a coil in the field, instead of specifying a single flow during design.

One example, for a new building, is a big CAD room with several work stations, cooled by its own fan- coil units. The owner will be selecting the computing, printing and plotting equipment later. Since you don't know the exact equipment load, which typically accounts for over 60%of the fan-coil load in such a room, you cannot specify the flow and you would rather not "guesstimate".

Another example, for an existing building, is that you are "tight" on chilled water. Due to renovation, you have to relocate three fan-coil units and install an additional two. If you do not distribute the chilled water properly among the five units, at least one coil will starve.

Figure 6. FLOW ADJUSTMENT OF A FLOWCON ABV CARTRIDGE WITH AN ALLEN WRENCH

The answer, for both examples, is valves with adjustable flow cartridges. Figure 6 shows a photograph in which the left hand is holding an internally adjustable cartridge.
The cartridge is removed from the valve by unscrewing a plug, without removing the valve or disturbing the line plumbing in any way. The cartridge is adjustable to any of 8 flow rates. As shown in the photograph, an Allen wrench is inserted in a slot and turned. Each 45 degree turn sets a new flow rate. The cartridge slot position vs. the flow rate (L/sec) chart is provided by FlowCon.Once set, the cartridge dynamically controls flow at the set L/S, over its wide control range.

The cartridge is made of non-abrasive and non-corrosive thermoplastic material, whose shape and properties will not change over the life of the valve. Stainless steel technology of this cartridge did not lend itself to the manufacture of this cartridge due to the adjustability feature.