In article
Ian Stirling wrote:
Rob Morley wrote:
In article
nige wrote:
Hi,

Trying to replace a heat exchanger on an ideal response 120
and the hexagon nuts wont budge a bit.
They do unscrew anti clockwise dont they??

Presumably you've already tried Plusgas. Heat would help, but it might
need oxy-acetylene rather than a propane torch. As a last resort
cutting them off is preferable to shearing studs.

I like heating to ~120C, then spraying with WD40, if possible.
The WD40 then boils, displacing air, and gets sucked in as it cools.

That method provides a bit of thermal shock which might be useful,
although I'm not sure that 120C is enough. I forgot to mention
attacking the exposed threads with a wire brush before undoing, and
wirebrushing everything and coating with copperease before reassembly.