@ reaper it looks like this:
(repeaters on the sides are just for looks, I had to add the one in the middle or it would sometimes just toggle on/off with the low heat monitor [high is on the left and low is on the right])
(A more compact version (also shows the orientation of the NOT gate better))
[Both the screenshots are with both monitors off (cold reactor) to show better. I tested both designs and they worked.]