Thermostatic Valve, fit to Flow or Return?

[Bottom]

I am trying to install a new single vertical radiator and need to know if matters if the thermostatic valve is connected to the flow or return pipes.

 

[Ben-gee]

It depends which valve you have , but most nowadays are bi-directional so it doesn’t matter.

However.

On a vertical rad quite often the direction of flow is critical - it should tell you this , but it doesn’t matter if trv is on flow or return.

 

[ShaunCorbs]

Recommend to fit on the flow pipe