(I'm a little warm because I was using lava to warm up) They don't work at all, both of the coils. I'm using the latest version of TAN, I have tried updating the Forge Version but the issue does not go away.

i too have this issue, but its also in a huge modpack, so there could be many issues, but without error logs, cant find out why :)

[1.12.2-3.1.0.141] my heaters work. they just need opaque blocks above them and heat spreads through them. coolers the same