My last house was a two pipe steam system with beautiful old radiators.
I moved in on Jan. 10. It was -20 that night and the house only got up to 55F. We sorted out the problem and the next night,
it was 85 upstairs and 65 downstairs.
We then installed thermostatic control valves on all the radiators and made the whole system work as well as it was going to.
Thank God oil was cheaper then.
I proclaimed the end of the heating season and took the recip saw to the hole system, except for the radiators.
BTW, the old oil boiler had a 12" flue
and some genius had installed a gate valve on the pressure relief valve
!
AND it was shut
! Rocket ship boiler in Bangor, Maine!
I plumbed it with 2-3/4" feed and return lines with 1/2" branches to each radiator. I installed ball valves in the basement wherever it fed the radiator.
I had to install coin vents on all the radiators (there was a plug where it went) and made the system into a hot water system and used the original lower fittings.
In hindsight, I could've done it with a manifold system, but this kept the plumbing in the basement to a minimum and got the heat upstairs faster.
Ran the whole thing on an outdoor reset controller.
My friend, Dick Hill did some wood boilers using old radiators as the boiler heat exchanger. Worked very well and even if bought new, was a pretty
cheap way to build a boiler from scratch!