A quick opinion from some Infinity/Evolution familiar person.
I need to hook up an indoor remote air temp sensor to my Evolution control. I have the OATS that was supplied with the control. On the package it clearly states not to connect to S1, S2 on the Evolution. In the install instructions, there is a note pertaining to what S1, S2 used to be for (outdoor air temp sensor) and what they are used for now (indoor remote temp sensor).
So, I'm thinking the warning is on the package because of the change in designation for S1, S2 and not because this thermistor isn't able to be used as an indoor temp sensor. My tech even made the mistake when they did my install. It was freezing outside but my thermostat said it was 72 degrees. He didn't realize they had an OATS connection right on the furnace.