Advantages of pre-setting thermostatic valves in radiator systems

[TSN79]

In a system of radiators, what would be the advantages of having thermostatic valves with pre-setting?

 

[Artman]

One advantage is individual control of space temperature. One drawback is that flow can be effected by the closing of the valves and will need to be bypassed once it exceeds about 20% of the system capacity.