Bumping this thread with a few questions.

I found this fitting next to the drain valve. Is this intended for a temp sensor? Would that be a good location for one? My thought is this is probably on the cooler side of the entire system as it's on the front side of the heat exchanger. Thread pitch?


If I wanted to purchase 90* brass fittings for the large heat exchanger ports, what size fitting should I be looking at?

These fittings: