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Sizing Steam Boiler

ttekushan_2 Member Posts: 57
based on fan characteristics and charts published by existing manufacturers.

Estimate based on fan diameter and motor rpm. Then find several manufacturer specs. CFM is really where the rubber meets the pavement. Based on average physical characteristics and CFM you should be able to come up with a reasonable estimate of BTU delivery.

Another good indicator is return trap size. Assuming (!) that the trap is not oversized, inferences can be made here also. If the trap seems oversized at first glance but the coil is a make-up air coil, it may be sized so that the coil doesn't "stall" on excess condensate with extremely low inlet temps.

Zero degree correction factors are typically around 1.5 times average conditions.

I may not get back to this site for a day or two, but I hope this helps.



  • tk_3
    tk_3 Member Posts: 36
    Sizing steam boiler

    I have a situation where a new steam boiler is going into an exiating system in a church. About half of the radiation has been removed and a new warm air furnace with A/C was installed. I have no problem calculating sq ft steam on existing radiation but there is also two steam duct coils. No rating plate or manufacturer name plate. Since we know what size pipe is going into the coil could we determine max sq ft of steam which can be carried by the pipes and size off that figure plus radiation load? Thanks in advance.
    EBEBRATT-Ed Member Posts: 15,344

    Measure coil legenth X width and thickness. Count number and diameter of tubes and fins per inch. Talk with a coil manufacturer they can get you close enough.

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