Firebox crack

Loop1

I am a Harry Homeowner, retired, who enjoys DIY projects. Every fall I clean and inspect my 15 year old Burnham oil fired hot water heating system. (Pardon me if I don' t use the proper terms in the following.) When I pulled out the Beckett burner from the "firebox" and looked inside, I found a horizontal crack in the "wall" opposite the opening where the burner goes. Not a wide crack, but obvious nontheless. Is this dangerous? Can I repair it with a coating of high temp cement (I can get to this cracked area by reaching in through the opening where the burner was.) Any thoughts and advice will be appreciated.

New England SteamWorks

I think a picture would be quite helpful.

STEVEusaPA

Which boiler model?
Can you show us a picture of it?
It's probably ok to leave it alone, if it's still tight to the back and remains intact. But it could be a sign of other problems. I wouldn't bother with furnace cement, it wont hold up.
If it's too bad, again I cant tell, you can take the whole front of the boiler off, and get a replacement chamber, which is usually a target wall (where you have the crack), a door panel, gasket material, and blanket for the bottom (if needed/used).
The instructions are simple to follow, and the job is easy to do. Remove all the old stuff, wire brush and vacuum, carefully put in the new stuff. Keep in mind you should run the boiler for at least a half hour (depending on the instructions), then check all the bolts, then re-do your complete combustion test with the proper instruments.

Loop1

Hate to be so dumb, but how do I post the picture I took?

STEVEusaPA

Thought the pic would've been bigger...click on the .jpg below for bigger picture

Loop1

Loop1

I assume the vertical crack is a seam between two parts while the horizontal crack is "not supposed to be there'"

Steamhead

Looks like a "target wall" and these are usually one piece. What model Burnham is this?

Loop1

It is Burnham Model RSA 85

Steamhead

This is a dry-base steel boiler. Not sure if this is true of yours, but on some of this type of boiler the firebox is very difficult to replace. Also, they're less efficient than wet-base cast-iron boilers.

Might be time to look at a new boiler. Do you have natural gas available?

Loop1

No gas available in the boonies where I live.

STEVEusaPA

Yeah that's about the only one that isn't easy, assuming you can get the parts. I don't understand why you need to be asked if you can switch to gas, but that's a whole other issue.
Like I said in my first post, could be a sign of other problems. You don't know how the rest of the chamber looks, and you might be seeing the best part. If you're going to fix it, or try to get someone to fix it, I would call Burnham first
http://www.usboiler.net/
and see what they recommend. If the parts are unavailable, then that's that. If heat went past/thru the crack and stressed/weakened the steel, you're going to have to replace it.