I'm installing in detached garage and this is my first time installing an unpressurized system. My house is pressurized and has old propane burner. I'll have to use flat plate connection obviously. Question 1. Should I run pressure system to boiler with flat plate in the back panel or make connection in the basement of house. Question 2. I want the ability of supplemental heat in garage but only have one set of hookups. Would think pull heat from return line somehow. Would guess flat plate to separate so I can add antifreeze to that loop. Next can that loop also serve as over run protection.