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Is zoning possible on old hydronic boiler system?

jac34 Member Posts: 63
I'm looking to replace my oil fired boiler serving cast iron radiators to a propane boiler in the spring; there are 24 total rads in the house. Currently, one thermostat runs all 3 floors and I would love to put 2nd and 3rd floor on one zone and have the 1st floor on its own zone.

Not knowing much about boilers, I'm following the pipes and it looks like 2" cast iron pipes coming off then branching into the risers which look like 3/4". Each rad has its own supply and return that seem to be accessible in the basement.

My kitchen/breakfast room were remodeled by previous owner in 2009 and put on its own thermostat. They installed an air handler in the crawl space that the boiler serves and then blows hot air over the heated coil through vents. When they did this, it looks like they capped some of the old radiator spots and ran new 3/4" copper pipe from boiler to air handler.

So, it seems it can be done but how costly would it be to zone out those rads? Seems labor intensive but what do I know?? Figure now is the time to do it when new boiler goes in. Unless it's a ton of dough, then I will just live with it.