@Bobby_M I agree with you, I was previously thinking similarly that the bodies were potentially the same. I didn't find an example one way or the other in a number of the parts diagrams. It wasn't an exhaustive search. I didn't want to be wrong (safety problem) and so I went with the language being used in the product descriptions and manufacturers web pages. Thought maybe it was a small part, or different calibration. It's not just homebrewers buying these, commercial operations use these too, before homebrewing started to use them, and the commercial operations have larger and more complex situations so I get what you're saying about the application. It would be useful if the manufacturers would mention that the secondary can accept tank pressure (and they might somewhere I didn't see it). Maybe they want to avoid users using the wrong tubing. Plus a triple bank primary would be top heavy, potentially awkward to situate vs a single primary and the remaining secondaries mounted on a wall or more convenient location. Even more than 3 would continue to exacerbate the problem.
