Danfoss FJVA 20 valves are for applications where, because of installation problems, etc., it is desirable to avoid using a capillary tube. This applies mainly where regulation accuracy requirements are more moderate and where an integral bypass can be accepted.

In FJVA the whole bellows element is used as the sensor. The valve reacts to the cooling water temperature and therefore it must always be installed in the return line. Thus, indirect regulation is involved.

To ensure the medium temperature to influence the thermostatic element, when the valve is closed, a by-pass in the valve provides a constant minimal flow through the valve.