How to identify feed and return?

[Danfoto]

When we gutted our bathroom earlier this year, I had to cut and cap off the feed and return to the rad so both the rad and the piping to it could cleared out the way.

I'm now about to start on the new plumbing, and of course my labelling of the two heating pipes has disappeared. The system runs off a combi boiler in the kitchen, and it's impossible to trace the pipe run back either visually or by knocking on it.

The only way I can think of to identify which is which is to connect the two pipes by a length of hosepipe, turn on the heating and hope to feel which pipe heats up first. Either that or instal the new rad, pipe it up (50% chance of getting it right!) and if my luck's out, cross the pipes over somewhere out of sight.

Anybody got a better idea?

 

[Avatar]

it depends on the system but it may not matter much.

Get standard rad valve, and swop the lock shield to the correct side when you fire the boiler, at which point the flow will become evident (first to heat up).

Balance the rad and bleed accordingly . . .

Might not work with a trv though.

 

[Danfoto]

Thanks Avatar! What an useless idiot I am. Hadn't occurred to me that if it's rse-about-face I just need to swap the valves round ...

 

[dontknowitall]

Or get a 2 way TRV - it doesn't seem to matter which pipe you put them on (but I do go for the flow if possible!)

 

[bm1289]

Bi-directional TRV. Fit,fire boiler, adjust arrow to pipe heating first......simples!!!

 

[metaldust9]

danfoss trv,s can go on either side

 

[shorticus]

ditto above go bi, oops, wrong website ha ha

 

[REDSAW]

just blow down the pipes.

and any more bad language will get your account suspended.....

 

[AceBeatnik]

Bi directional valve, no bother, no swap. In fact you'd do well to buy a trv that wasn't bi-directional nowadays!