A three-way valve has three ports that either mix two inlet flows into one outlet or divert one inlet flow into two separate outlets. These valves enable complex control strategies including supply temperature blending and circuit isolation. They come in mixing and diverting configurations depending on application requirements.
Technical Details
Three-way valves are available in equal percentage and linear designs with sizes from DN15 to DN150. Mixing valves combine warm and cool water to achieve setpoint temperatures, while diverting valves direct flow between multiple circuits. They typically have 250 psi to 600 psi pressure ratings and require two-port authority calculations for each flow path.
Applications in HVAC
Three-way mixing valves regulate supply temperature in heating loops by blending return water with boiler discharge. Diverting valves switch flow between active and bypass circuits or between heating and cooling sources. They are essential in changeover systems and supply temperature control applications.
Practical Significance
Three-way valves cost 30-50% more than two-way types but provide flexibility for complex control strategies. Proper sizing requires analyzing each port flow path separately. Automatic control with thermostats or building automation systems enhances their performance and energy efficiency.