rad size mind boggle

nocon

i just replaced a not to old burnam v8 . with the mega steam . 2 2" mains 2 returns put hoffmann # 75's on returns hofman a1s & dan foss non electrics on some with goton #4s , rooms still overheat . i suspect the radiators are to big , it was once a house now its several efficiency apts , the radiators are american radiator 5 column no threaded rods , so i suspect there threaded together , no place for rods! im confused i get conflicting sq foot calcs from burnhams site , the lost art of steam , & others ! i have access to a pile of weil mclain 6 column rads , that i can adjust to size , the confusing part is the 5 column american rads ; most of them 10 + sections are wider & longer than the weil mclains wen the same sections are counted , i cant find specs for the american rads , i dont see how the size charts are accurate , the 5 column 1's are physically larger than the slim 1's how can i accurately no the size , im leaning toward the slim 1's ratings to be more accurate , when i added up the edr using burnhams method i came up with 385 sq' i even acounted for the 1 i found in the basement , like dan said i would find

nicholas bonham-carter

Swapping rads

Remember that the valve and spud of the radiator are a matched pair, and that you will most likely have to get new valves, as the spuds are difficult to remove.

Tell us more about the symptoms you are having, and we can advise.

When an older house has had its insulation upgraded the balancing of the system, and thermostat placement become much more important. I suspect you may may have venting problems, and that steam is favoring certain radiators first when the steam "arrives". Fix these details first and then see if you need to do any switching.

Put lots of main venting on downstairs, and little hoffmans on the rads, and see what effects that will have.--NBC