Just getting back to MEP after a few month hiatus, and am wondering how to create a loop in my mechanical room with closely spaced tees. Input from the boiler, output to the heat emitters and a hot water tank ( a very basic and common design). I understand creating, say, a supply system and return system to/from the emitters, and to/from the boiler, but I need an intervening "primary loop". What's the strategy to do this? Thanks!