Detecting greater than instead of greater than or equal to doesn't help when you've cooled the TSNS so that it detects cold things. Setting temperature is easier than setting tmp2 (particularly for people who don't know how to use the console). That's why the default was changed to tmp2=1 - so that a 1px gap can be left between TSNS and the conductor and it will work fine with cold things, without having to change tmp2.
However, the ctype thing sounds interesting.
OK, I checked what you said about the screen scale 2, it's true: if I disable large window it reads pressure perfectly fine, even in fullscreen mode. Large window size seems to be the problem. I like to play on scale 2 because it allows me to actually see a thing (scale 1 is ridiculosly small) while being able to switch windows to do other stuff without having to exit fullscreen with alt+tab (too slow). It's nice that you found the problem, I'm gonna wait 'till your mod's next version to play on scale 2 without fullscreen. Thanks for your work man.
How come tsns detects what its conducting to? I understand that it's a "equal or greater temperature" but shouldn't the particle its conducting to not count? Also the particle eraser erases walls if your flood fill erasing.