Balancing Cast Iron Radiator

Mudaero

Is it better to balance a cast iron radiator at the radiator or at a manifold? I am adding manifolds to my boiler system and replacing the steel pipe with pex and am trying to determine the best option. Are the high end manifolds (truFLOW, Caleffi, etc.) with balancing valves and adjustable flow meters a better long term decision even if more expensive than a valveless copper trunk manifold? The zones are small (4 circuits max) and I am trying to minimize cost and would prefer to use the copper trunk if the radiator's balancing valves will work equal or better than the manifold's. But, if the manifold with all the nice gadgetry functions better and is good long term investment, I would go that route. Any suggestions and opinions are appreciated.

SWEI

The flow meters, actuators, and balancing valves on a full-featured manifold are convenient, especially for radiant floor/wall/ceiling systems where the flow rates for each zone are provided as part of the system design.

On a retrofit like yours, balancing is probably going to be done over time, as you live with the system. As long as your existing radiator valves are in good shape, they should work well for balancing. If you're replacing all of the existing piping, the overall system should balance fairly well. If this is an old gravity system and you only replace some of the piping, you may have trouble maintaining balance especially as the load shifts with the weather. I would suggest piping the manifold supply loop as a reverse return.

Mudaero

I will be replacing all of the piping, save for the 1 foot of steel pipe off the radiators in the main floor, and the 10 feet of steel that runs vertically to the second floor. I will be adding fin tube elements in the basement, however.