Hi Brendan,
I've looked into the ratcheting sound and have a hunch on why the issue you describe is happening, and how it can be fixed, but until it is fixed I would suggest avoiding warm mode so that you don't get the annoying ratchet on an insanity inducing loop! I've also traced down the exact issue causing the water gauge problem as described by Anthony, and hopefully it can be fixed promptly. There is also a snifter valve problem which I believe I have now fixed, and an AWS sunflower problem. These are the only issues left that I am aware of.
It will all be sorted out for another update that hopefully won't take as long to release, fingers crossed. I apologise that further issues crept in with the update before Xmas; it was disappointing to read about there being further problems after all the work that everyone in the team put into the update, although on the whole I think we made it better than it was when released in October, with better simulation, physics, sounds, lighting, firebox, water scoops etc. I am very proud of the 5MT and the team behind it, and hopefully we'll have ironed out all of the remaining creases for good next time.
Kind regards,
Chris