u/ohboymyo

I noticed my double boiler was leaking in the back right of the machine. I took apart the top and watched it in operation but didn't see any particular leaks from the hoses. I opened the back and behind the white control box I saw a loose blue o-ring that I can't seem place. I don't see any loose hoses. It's possible the previous owner worked on the machine but I wanted to check with this Reddit to see if anyone could place this o-ring.

I also included pictures of corrosion in the general area to see if there's advice on what to do here. I do have the spare o-rings and plan on replacing all of them on the boilers but just concerned I'm missing something.