Left a piece of cloth inside 15mm pipe

[Mike_M]

So I think I've made a really stupid mistake. I stuffed a bit of rag into the pipe end to stop drips while I was preparing to solder. Then I put the new fitting on and soldered it. I didn't realise and tested the heating which worked but then got a low flow on the boiler. It was then I realised my mistake. Any advice on how to flush out the rag please. I've taken off 2 of the 3 downstairs rads and flushed them out, but no sign of the rag.

 

[Chuck]

Try using a thermal camera to survey the suspect pipework while the heating is running.