I need to control an extra fermwrap right now. I have Ranco digitals on my other ones but I have an older Johnson A19AAT-2 that I usually keep for cooling only.
I opened it up and; the cover, of course, states "Close on Decrease" and it's currently wired to COM and 2...has a "3" slot, which I'm assuming that I would swap the hot wire over to, provided this particular model can support that.
I couldn't find any literature stating that the AAT-2 was or was not capable of "close on increase".
I would think that if you've used the Johnson Controls for cooling that it would be the "close on temperature INCREASE" so that the compressor starts and cools it down until it opens on decrease.
Data I've seen on that unit says it has a SPST switch which would be just the two terminals for wiring. Most units I've worked with that have 3 screws factory-equipped are SPDT switches which would probably work for your application. If the 3 slot has metal in it for a screw, it may work - check it with a meter. If not, the same plastic housing may be used for both types but the inside is different in which case you're out of luck.