Sealed-off pipes - which is flow and which is return?

[edwardtsmith]

Hi,

I am in the process of installing a UFH manifold in a cupboard that fortunately has two old pipes running through it from the boiler. They have been cut and sealed - obviously (I hope) an old connection to a radiator.

These would be ideal to use as flow and return to the UFH manifold, but I don't know which pipe is which - are there any tricks to find out? The pipes disappear through a wall and behind cabinets and so will be almost impossible to trace back to the original boiler connections.

Thanks,
Ed

 

[Dan Robinson]

Cut off the caps, and fit lever valves. Link the two together and see what gets hot first.

However.... depending on various things they may not provide enough heat/flow to run the UFH sufficiently.

 

[edwardtsmith]

Thanks - nice idea.....

Would you not need a reasonable amount of pipe between the two to be able to distinguish which gets hot sooner?

I am fazing in the UFH circuits in one by one as I refurb my entire downstairs. Therefore, initially I will only have a small load on the UFH, then later I will install full 22mm all the way to the manifold once I rip out the previously mentioned cabinets...

 

[Dan Robinson]

Just use a piece of barrier pipe, length of your choosing and create a suitable loop. You only need a foot or so. Get someone to turn the heating on whilst you hold the cold pipes.