Balancing hydronic system w/ cast iron rad

Padraig

hi. I have a cast iron cold start boiler with an indirect water tank. In slab infloor heat in basement—4 way mixing valve for low temp. Cast iron rads up stairs—each rad has home run loop. I have 4 zone valves for infloor and 2 zones on upper 2 levels—floor 1 zone, floor 2 zone. I’m having trouble with balancing the cast rads and getting a good tstat location.
does anyone have any ideas as to how to make this as comfortable as possible. Btw the cast water temp high limit is set at 170F, and I don’t have any radiation valves.
thanks.

hot_rod

do the manifolds for the home run radiators have balance valve?

You would be able to dial in each one to a close flow and output