How to open nut that is closed with flax fibers?

[bennyzamir]

Hi

I would like to know how to open nut that is closed with flax fibers (I can't open or close the nut) ?
I have a leak in the area of the nut . the nut connected between a copper pipe and the boiler.
Is there any way to stop the leak without open the nut?

Thanks

 

[plumb_bob_square_pants]

I would say no. Power down, drain, and repair it.