It's an industry standard: if a furnace has a cracked heat exchanger, it gets replaced. The American Gas Association has even put this in writing - they say "Any visible crack or hole is reason for ...

This completely DIY casting furnace turned out just great thanks to all the work [Biolit11] put into it along the way. He wanted to replace his older furnace with one that was more efficient, and to ...

Q: I need to replace my ancient forced-air gas furnace. I have a 2,800-square-foot house on three levels. It's in Oakland and was built in 1922. The current heater is inefficient, perhaps because it's ...