PI valves are dynamically balanced delivering the proper flow to the coil over any operating load condition. Overflow and underflow are eliminated providing better comfort and efficient system performance. PI valves perform the function of a balancing valve and control valve in one unit.
Mechanical PI valves such as PICCV and PIQCV combine a differential pressure regulator with a 2-way control valve to supply a specific flow for each degree of ball opening regardless of system pressure fluctuations. Travel adjustment is used to achieve full flow (V’max) when coil design flow is less than the full capacity of the valve (V’nom).
Electronic PI valves such as ePIV or Energy Valve reference live flow readings sourced from an integrated in-line ultrasonic or magnet flow meter to throttle the 2-way control valve to obtain the flow setting - just like pressure independent VAV box actuator behavior. Full flow (V’max) settings are programed into the actuator and travel adjustment is not necessary because the available differential pressure across the valve orifice determines the actual flow.
For Energy Valve information click here
For PICCV and ePIV information click here
For PIQCV information click here