Something is hissing, hammering, frozen, roasted, or short cycling. Another service call is dispatched to that building. While simple, the water control valve is one of the main components used in HVAC control. Therefore, valve sizing is one of the most important tasks when designing a control system. Properly performing this task involves using tables or calculations to determine the best size valve for the specific application.
Capacity is one of the major considerations when sizing a valve.
The valve must be large enough so that when open, full flow is delivered to the coil. The valve must also be small enough so that at low load conditions, the valve has enough modulated stroke to afford good control. The goal is to select a valve with a Cv which will offer good control and capacity. Once the correct Cv is found, the appropriate valve may be chosen from the Kele catalog. A table is often used to get the correct Cv .