Can't find replacement fuseable 3/4 plug to fix leak into firebox on old Kalamazoo Boiler

My buddy has an old Kalamazoo boiler that suddenly started dripping water into the firebox from this "fitting" found at the top of the firebox. It seems to thread into where the heat exchanger is at the top, and is found directly under where the pressure and temperature gauge is.

It appears as though it simply unscrews and can be replaced, but what is it? I'm assuming it's not unique to this stove and hoping it's something that is rather universal.

Thanks if you can help lead me in the right direction for a replacement.

Here's what it looks like at the top of the firebox in the boiler. The water is pouring directly out of this "plug"



Sorry for the sad picture. To describe, it looks like a 13/16 or so deep well socket will simply unscrew whatever it is.

It appears as though it's found in the firebox directly opposite the pressure / temp gauge.



Thanks

Thank you!

Here is what the plug this boiler looks like. However, I can't seem to find this style in 3/4 which is what i need.

Know of any other suppliers or suggestions? My searching hasn't turned up a direct replacement.

Thanks

Also what temp rating eould this be? In searching, there seems to be different temps for different plugs.

Pics

Still haven't been able to source one of these. Any advice?

Thanks,

pen

Found out the thread was locked,,,, thank you @DoubleB ! Got that fixed.

I can find similar fuseable plugs in different sizes or configurations but not one that will match this. Any advice would be great.

Thanks

http://www.elsiemfg.com/product-category/plugs/pipe-plug/brass-pipe-plugs/

Has plugs up to 1/2 inch, but not 3/4... Someone must carry them, I just can't find them.