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boiler sizing

I am replacing a 10 year old Burnham steam boiler with a cracked section. The current one is a 6 section gas fired one. There are convectors throughout the house being used as the source of heat. I have never seen this type of radiator being used in a steam system before. I believe that the current 6 section is grossly oversized. I was wondering if the type of convector being used had something to do with the last installer sizing it the way he did. The house is about 2000 sq ft with old windows and no insulation. probably built in the 20's or 30's. The convectors are 5 1/2" wide and 2" thick with 3 tubes running horizontally the total length of the convector and they are covered with steel finns just as traditional hydronic convectors are. There is a total footage of 30 ft of convectors throughout the house. There is also one 24" long by 24" high 4 1/2" wide 4 tube free standing cast iron radiator on the system. There is also about 80 ft of 2" steel horizontal main in the basement. The customer wants to go back with a Burnham again. Shouldn't a 4 section do the job? Or do the convector style radiators add something to the equation that I am missing?


  • Ironman
    Ironman Member Posts: 7,342
    You need to find the total sq. ft. of EDR for the convectors and select a boiler with a matching sq. ft. of steam rating. The boiler MUST be sized to match the radiation with steam.
    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
  • Fred
    Fred Member Posts: 8,542
    Not only must the boiler be sized to the sq. ft of connected EDR, it needs to be piped correctly, at a minimum to the specifications in the installation manual. If you don't know steam, follow those instructions or pass on the job. If you post a picture of the convectors and that radiator, on here, we probably can help you with the sizing.
  • joe amadio
    joe amadio Member Posts: 41
    Thanks Fred. Will do that tomorrow