Radiator flow question

[MickyP10]

Had a extension added and plumber 'T-eed' into radiator on other side of wall. Thing is, the TRV on the hall radiator is on return and in the extension, on the flow. Someone mentioned modern TRVs aren't too bothered which end they go on, but what about balancing? Can/should I try and balance by reducing flow (ie with TRV) or should I swap the TRV and lock valve over and balance with lock valve?

Reason for asking, is airy noise in pipes.

 

[wiggikins]

Provided TRV'S are bi-flo leave them as they are and vent the rads.

Keith.