Wood Boiler using Cast Iron Radiators

Motox2

I am new to this forum and seeking some advice.  We are installing an Outdoor Wood Boiler to heat an old school house (now a residence) and we will be heating part of the structure using some of the old cast iron steam radiators with hot 175F water.  I am looking for input/advice on plumbing and controls for this project.  Most specifically how to plumb the radiators.   Part of the home will also be heated using two forced air systems with water to air coils in the duct plenum using hot water from the wood boiler.

Big Ed_4

Steam Radiators

Check first if you have steam only radiators , if only connected though the bottom by a passageway you can not use them for a hot water system . If connected by passageway top and bottom , you can use these for both steam or hot water....



You want to pipe cast iron hydronic either by diverter tees or a home run system ..



With diverter tee system you would run a larger main pipe large enough to handle the load of the zone .. The load is the heat loss on the coldest day of the year .. From the main you need to run smaller risers up or down to the radiators from tees on the main .. These tees are either reducing tees or vanturi tees .. One vanturi tee is installed on the return riser of the radiator on a up feed radiator and use two tees for a down feed radiator ..The distance of the tees or risers need to be spaced at least the length of the radiator connected .. The risers are best installed with a upward rise so air will rise up into the radiator to be vented out ... If not a purge valve set up needs to be installed on one of the risers ...Another note if the radiator was used for steam and could be used for water , a bleeder needs to be added near the top of the radiator .... Vents on steam use the half way tap .....



Did I loose you so far ??



Best off starting with a heat loss calculation of the building , Then figure each zone , Every floor or wing should be zoned .



Now if you can use those rads for water , Find out the EDR of the radiator.. One EDR equals one square foot of surface area , find out the output of the system temperature running through them ..



With the knowledge of the out put and the heat loss of the rooms in the building you can figure what goes where .. The larger the output of the radiator over the heat loss , the cooler the water needed ..



This is just a start ...