WE HAVE A VERY OLD HOME AND IT HAS RADIATOR HEATERS AND A NEW BOILER SYSTEM WAS PUT IN 5 OR 6 YEARS AGO..WELL AFTER DOING SOME READING IT IS ACTUALLY STEAM NOT WATER THAT HEATS THE REGISTERS..WELL WE WANTED TO TIE IN WOOD COAL BOILER SYSTEM WITH THE FUEL OIL SYSTEM BEING AS FUEL OIL IS HIGH BUT NOW ARE BEGINNING TO THINK IT ISN'T POSSIBLE..WE WERE GOING TO BUY A HARMAN DOMESTIC BOILER ANY SUGGESTIONS OR KNOW HOW THIS CAN BE DONE...