sizing steam boiler with major changes

Roger Litman

I have a customer with a steam boiler rated for 4650 feet of steam, it is being fired at 1.61MM btu per hour. I ve measured the radiation on the remaining three apartments( originally there were 5, all are large) and could only find about 1100 feet of steam. The main heaqder is 6 inch pipe. Am I right in using a boiler that is rated for 2021 feet of steam and using two 4 inch supplies or am I going too large or small.

Jamie Hall

You always

size the boiler to the connected steam load.  Now, having come up with that rather obvious statement... even the 2021 sq. ft. boiler might be a bit large -- assuming that you really have found all of the loads.



Is there a reason for changing the six inch header?  If you make sure that it is well insulated (1 inch minimum) it won't hurt anything being there, and if it simplifies the repiping, so much the better.  Two four inch will work just about as well, though, again assuming they are insulated properly (they have about the same area, so the velocities will be about the same, but they have almost half again as much heat loss, so the insulation is even more important).