Should indirect tank be considered when sizing boiler?

tim smith

But if you have a real small heat load it may come into play when you have a small indirect tank like yours. I would say if your load was somewhere around 70,000 or so, then I would not add any as the recovery of a 40 gallon tank w/ 70mbh input will reheat tank in less than 30 minutes. But if your load is only 35,000 or less, then recovery rate on that small of tank would be a bit slow with on that many btus, so I may oversize for that reason. Tim

stacie b_2

For a one-pipe steam system...

I calculated the square feet EDR of my radiators and convectors...but I'm not sure if you are supposed to add anything to the equation when there is an indirect hot water tank attached? If so, what is the formula? I have a MegaStor 40 gallon tank. Thanks, Nelson

stacie b_2

More boiler sizing info...

Thanks. I calculated my total radiator EDR to be 285 sq. ft. and the contractor is recommending a Burnham MegaSteam with an IBR of 396 sq. ft. The MegaSteam also is available with an IBR of 288 sq. ft. They recommended we get the 396, since the indirect is attached, and "downsize" the burner instead. There is no price difference in the units, but with all I've read about proper boiler sizing, I want to make sure we're making the right decision. Any thoughts?

jp_2

thats a good question

Is a steam boiler a good match for making hot water during off heating season?

is the short maintenance heating cycles good/efficient for a steamer? meaning calls for standby to keep tank up to temp?

may be this a better job for an on-demand water heater?

how large are your typical hot water needs per day?

a 40 gallon indirect will consume about 4 million BTU's per year just to have hot water on the ready, on-demand zero!