Summer of 2010 the 25 year old cast iron boiler which heated our 6 unit condo building began showing signs of serious structural damage. We needed a new boiler right away. We were planning to replace the old boiler with a new unit of the same cast iron design. Then our condo association heard about a “green” alternative choice: a steel boiler designed, manufactured and installed by Rayes Boiler, a company based in the Chicago area ..