What Is This?

belovedamerican · Post by **belovedamerican** » Wed. Nov. 25, 2015 8:55 am

Anyone help me identify what happened here? I've been burning coal for three years in Harman sf 260 and I've never seen this before. It doesn't disappear if I rub on it (and it even feels like it has slightly raised edges). I do seem to recall brushing some coal away from this area before I noticed it. I do not load my coal above the fire bricks but I do mound in the middle. Any help or ideas would be appreciated.

Hambden Bob · Post by **Hambden Bob** » Wed. Nov. 25, 2015 9:27 am

Welcome ! This kinda reminds me of a corrosion rust bubble coming out of the steel. It would be interesting to see what it looks like below the firebrick line. Did You do any corrosion inhibitting after last season's shutdown and cleanout? Was Your unit exposed to high humidity during the off season? That's my guess,but We have so many more High Intelligence Critters here than me. Trust me ! In the end,I'd make sure I had replacement firebrick available,let it go cold,cleanout and remove the brick to inspect.....Good Luck !

belovedamerican · Post by **belovedamerican** » Wed. Nov. 25, 2015 9:34 am

Thanks for the reply. I actually replaced the fire bricks this summer. Nothing like that underneath it. Also, I have two lights in the unit during the entire summer so it stayed dry.

Hambden Bob · Post by **Hambden Bob** » Wed. Nov. 25, 2015 9:50 am

I'll be damned. Sounds like You've been a Stand Up Stove Owner in my book! Did You highlight both areas by making the dark circles,and then putting the arrows on them to point them out? If not,it's almost reminiscent of the look around a spot-weld.

Post by **Lightning** » Wed. Nov. 25, 2015 10:54 am

That's a boiler right? I believe there are cylinder shaped steel studs that run between the inside and outside of the water jacket. I'm betting the location in question could be where two of these studs are mounted. But I don't understand why they weren't noticed in the past.