Pressure Independent Control Valves or Pressure Independent Balancing and Control Valves – also commonly known as PICVs (or PIBCVs) – are getting more and more popular in both 2- and 4-pipe heating and cooling applications due to their accurate flow control at any load condition.
A PICV includes three valves in one body by combining the control function, the balancing function and differential pressure control function in one unit.

• Control
The control function of the PICV, as with any other 2-port control valve, allows load dependent flow variations from selected design flow (100% load) and down to closed valve (0% load). By varying the flow rate, the heat output of the terminal unit is controlled and will provide optimal room comfort. The key to the optimal solution is to choose a true PICV with 100% authority using full stroke or multiple rotations when regulating to reduced flow rates.

• Balancing
The key to the optimal solution is to choose a real dynamic balancing valve including a rolling diaphragm which at any time will self-balance to the required flow independent on system pressure changes. The balancing function shall be easily adjustable to several max. flow settings (minimum 41 different) in the same PICV.

• ΔP control
With changing load requirements in the system, system pressure will also var. This calls for an automatic balancing solution which instantaneously compensates for the pressure changes by adjusting the flow outlet with the rolling diaphragm as described above under balancing.

Application
Heating or cooling, Fan-coil units, Air-handler units and other terminal units - wherever dynamic balancing and fully accurate temperature control are required.

Application Example
Fan Coil Unit with Pressure Independent Control (PICV) - Modulating Control.

Pressure Independent Control Valves with 100% Authority
The FlowCon Green insert is designed as a 3-in-1 solution combining a full stroke modulation control valve, an automatic balancing valve and a differential pressure control valve. This insert includes an innovative diaphragm-based self-adjustment feature, which enables each valve continuously to self-balance. This ensures delivery of precisely the flow rate required by each terminal unit, independent of pressure fluctuations in the system. In addition, each insert can be adjusted to set an accurate maximum flow limit to each circuit without stroke limitation.

The FlowCon Green is a 100% authority pressure independent flow control valve which instantaneously self-balance at all points of operation, even when there is variance in pressure differential. As long as the pressure differential across the valve is within the operating range, the valve diaphragm is regulating nonstop ensuring constant differential pressure across the regulating element and thereby ensuring full authority. FlowCon Green will in other words always provide 100% authority for any of its stepless-set 41 maximum flow settings, while maintaining full spindle stroke.