Piping radiators. All aspects of plumbing questions and answers, help, tips and information

[Bennett]

Hi. I've been told the most efficient way to pipe up a radiator is to put the flow into the top of the radiator and the return at the bottom opposite side. is this correct ?. If so would the best place for the TRV be on the return ?
Also when my heating pump starts there is a loud rushing noise of water which then settles down. Is this normal ?

[htg engineer]

Depends on the type of radiator you buy, not many top entry radiators around now. Standard practice is to fit the flow and return to the bottom of the radiator (doesn't matter what end).

With most TRV's it doesn't matter whether you fit them to the flow or return. Check the instructions for the TRV's you buy.

[bonzo]

If you've got a Combi boiler then piping up this way will be pointless as it's all pressurised anyway.

If you've got a normal gravity system then the water will flow through the radiator slightly better creating a better spread of heat, but the benifit of this in my opinion is outweighed by how terrible it looks when piped this way.