Flow and return on radiators

[m4ckg]

As the title suggests, how do you determine the flow and return for the rad valves ?

[B17NNS]

Usually the lockshield valve is on the return however it is no guarantee.

TRV's are often not directional so can be fitted either end.

Wait unti the system is cold and turn it on. The flow pipe will get hot before the return.

[m4ckg]

B17NNS said:

Usually the lockshield valve is on the return however it is no guarantee.

TRV's are often not directional so can be fitted either end.

Wait unti the system is cold and turn it on. The flow pipe will get hot before the return.

I know that most trv's are none directional but the one I want to fir to my bathroom is for a Vasco rad and they are quite specific for the supply and return. I will try your suggestion on testing the pipe once cold. Thanks

[Ferg]

B17NNS said:

TRV's are often not directional so can be fitted either end.

This isn't quite accurate, to be honest, although the small print IS small!!!

You CAN fit most new TRVs on either end of a radiator, BUT there are definite flow-rate parameters to be met. Many, if not all, will still chatter if they are flowing too much water which will occur if te others shut down. Obviously a differential bypass valve will sort this out, but many y-plan or combination boiler systems are fitted without one.