Serious question, my foreman told me to always use a 3/8 inch gap on that old boiler in St. Louis and it cracked the header after 6 months.

He said 'it needs room to breathe' but the thermal cycling was too much, so has anyone else had to re-weld a header on a 1920s unit because of bad expansion gap advice?

2 comments

2 Comments

seanh9122d ago

Wait, a three-eighths gap on a St. Louis header from the 20s? That's wild. I've seen a sixteenth work on some of those old riveted sections, maybe an eighth at most if the runs were long. Three-eighths is just asking for it to hammer itself apart every time it fires, no wonder it cracked. That's not breathing room, that's a highway for stress.

brian_jackson21d ago

My uncle's shop in Toledo still has the 1925 Erie they fixed after a similar gap mistake. Seanh91 is right about the hammering, you could hear that thing clunk from the parking lot on a cold start. They ended up sleeving the whole uptake to stop the flex.