Quick Guide How to install a FlowCon PICV Insert

1 April


In this day and age, many hydronic systems are designed with Pressure Independent Control Valves, harnessing the energy and cost savings potential these valves offer.

The Danish manufacturer FlowCon, inventors of the PICV valve concept in the mid ‘80s, and today the world’s largest HVAC-specialised dynamic valve manufacturer with an installation base of over 10M valves in more than 60 countries, offers a unique modular PICV valve concept for connection sizes from ½” up to 1 ¼”, comprising a valve housing and separate composite insert, which contains the regulation element, effectively the PICV.

The separate insert concept provides a great deal of flexibility to users. Should the control characteristic, differential pressure or simply the flow rate requirement ever change for a system due changes in occupancy or technical reasons, e.g. a pump upgrade, the insert can easily be exchanged in the live system to meet new specifications, without having to remove the entire valve and to isolate and drain the branch.

While Flowcon Pressure Independent Control Valves are practically maintenance free, local circumstances and water quality issues can lead to service requirements, which are easy to fulfil by simply cleaning or replacing inserts. For new installations it can be a consideration to flush & fill the system without PICV inserts installed (BG29/21 amended 6th edition), in which instance a blank cap would replace the insert during flushing.

Install a FlowCon PICV Valve Insert in 5 easy steps 

The quick guide covers an insert installation in a valve housing within a live system after flushing with a blank cap OR replacing an already installed PICV insert. Please be aware that this quick installation guide is only applicable to FlowCon Pressure Independent Control Valves!


  • Identify the insert size required for the Green PICV. The housing that covers ½”, ¾” and 1” connection sizes requires a 20mm insert and the housing for 1 ¼” and 1 ½” connection sizes requires a 40mm insert.

  • Identify the insert type. There are 5 20mm options available and 2 40mm options, each with 41 stepless set points.

5 easy steps to install a PICV Valve insert in a live system

  1. Isolate the PICV. Flow first, then the Return. On a terminal unit, isolate the flow and return of the flushing by-pass valves. Note the handle positions when the PICV is isolated!                                                                                                                                                     
  2. Check that the PICV is isolated by loosening the blank cap or insert by slightly turning it in an anti-clockwise direction without removing the blank cap or inset. After confirming the PICV is isolated (no egress of water) the cap or insert can be fully removed.
  3. Install the insert. Gently fit the insert into the housing. The insert can now be screwed into place by turning clock-wise by hand to avoid cross threading. A socket or spanner can then be used the screw the insert fully in. Once the insert flange comes in contact with the PICV housing the process is complete and will seal perfectly. Do not overtighten the insert!
  4. Confirm that the system operating pressure does not exceed the rating of the valve.                   
  5. Equalise the pressure across the PICV by slowly cracking the return isolating valve. After 2 to 3 seconds, the return isolating valve followed by the flow isolating valve, can be fully opened. This will protect the insert diaphragm.

The PICV insert is now installed safely and the flow and return valves can be opened and closed without risk of damage.

Stay tuned: We will be publishing more “How To” posts and videos specific to FlowCon Pressure Independent Control Valves in typical UK applications in the coming weeks. For specific support please contact us directly.