A manifold based central heating system (star shaped) has several advantages over traditional "ring" system:
Time required for installation is significantly reduced;
Overall cost of the system is also reduced due to the lower number of fittings required (tees, elbows, etc.);
Efficiency is increased. This is due to the fact that all radiators and/or underfloor heating pipes are feeded with hot water directly from the heating body (wood burning boiler stove, pellet boiler, solid fuel boiler). With the traditional "ring" system each consecutive radiator is feeded with cooler water which increases the time needed to heat the room and respectively the fuel needed.
Primary connection size (inlet/outlet) is threaded 3/4" and the port size is threaded 1/2". Number of ports varies by model.