One of our radiators just went bad. It was made by the H. B. Smith Company, has 12 sections and is approximately 38"x9"x22". It says "Princess 3" around the inlet pipe. My heating contractor suggested a 4T-25H-14 (U.S. Boiler, 4 column, 25 inch high, 14 section). I want to figure out the EDR of the old radiator, so that I can verify that this is an appropriate replacement. Can someone point me in the right direction on how to do this? I googled "H.B. Smith princess 3" but didn't find anything.