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SIZING CONSIDERATIONS
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Sizing Electronic Control Valves
For the most comprehensive procedure in sizing Electronic Control Valves, it is best to use our ValveMaster software. In it’s absence, the following procedure will generally suffice.
- Decide whether a globe or angle valve will best fit your installation. Keep in mind that it is always best to install any control valve “bonnet up,” particularly in sizes 8” and larger.
- Begin with a line sized valve. Calculate the pressure drop from the formula,
 where:
DP = pressure drop, psi
sg = specific gravity of line fluid (water = 1.0)
Q = Maximum anticipated flow, gpm
Cv = Valve coefficient from Table 2.
- The pressure drop calculated is that for a wide-open valve. However, these valve are modulating and actual pressure drop seen could be higher, dependent upon the valve function (i.e. pressure reducing). Because the calculated pressure drop is calculated at maximum anticipated flow, it is useful to ensure that system capacity is not exceeded.
- Check to see that the flow velocity does not exceed 20 ft/sec. If it does, or if the pressure drop is excessive, consider using the next size larger valve.
FLOW CHARACTERISTICS
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