Owner

stevelaw

I have an existing oil-fired steam boiler (cast iron radiators) that's about 50 years old and operating with no significant problems.  I have been advised that it would be to my advantage to replace the boiler with a more efficient one and a starting point would be to match the boiler to the existing radiator and pipe system.  Is there a simple procedure for doing this?

STEVEusaPA

some thoughts....

First, who advised you and why?  What were the reasons?  What's the current efficiency, and what is projected for a replacement boiler.  Let the contractor prove this to you, and do the work resizing.

I would recommend a complete heat loss of the building.  If some upgrades have been done (windows, insulation etc.) you may be overheating your house, maybe you (they) could redesign you system to make it burn less fuel.

To size your existing radiator/piping, grab dan's book 'how come", it has EDR tables for almost all the radiators, and for piping.  Add all these up and that will tell you how many BTU'S you'll need.  But that's just your starting point.  You'll need a whole system evaluation to make the proper size and equipment choices.

lchmb

steam system

A steam system is sized based on EDR, not a heat loss. Dan has a book that list's your radiators and how to find the actual size of each. I would allow your installer to do this, if he's comfortable with steam..

http://www.heatinghelp.com/files/posts/8970/Boiler%20Sizing%20Chart.pdf

STEVEusaPA

responding to Ichmb

Of course I realize a steam system is sized on EDR, not heat loss, my remarks were based on the consideration that if it was installed over 50 years ago, it was probably oversized then, and if updates were made to the home, windows, insulation etc., it's probably more oversized now.  Just if your going to replace, take a fresh look at the BTU needs.  Maybe you need less radiators, smaller radiators, you can do some re-configuring to get some better comfort.