Heating Help

1" pex for loop to rads

Can I use 1" pex for supply and return loops to my cast iron rads? I want to replace old 1 1/4" steel pipes and want to do a reverse loop when I change it out. It's roughly 100' loop around the perimeter of the house. I will branch off with 3/4" pex with 11 branches, 9 rads and 2 baseboard runs. I know I will need a new circulator, which isn't a problem, it's older and noisy. Thanks

Is it possible?

Is it possible to rum a 1/2" supply and return to each radiator and back to a manifold near the boiler? You could have individual control of the radiators with trv's or zone valves.
Carl

Yes

Yes I could. That was another option I was thinking about. I guess I'm just trying to keep it simple and the cost down?? I'm guessing this would be a better option for performance, efficiency and comfort? I could zone the two floors easily if I wanted. FYI... I'm using a mod/con boiler.  Thanks

Home run

I think you will be happier with the 1/2" home runs. Trv or zone valves depending on the layout. A delta t ECM circ and primary secondary would work well with the mod/con.
Carl