The radiation is Slant Fin I believe Dan said, and is all 3/4" copper feeds and returns. Grundfos Circs and the Circ controller that is wired independently of the boiler. Don, check to see if there is a jumper across the TT terminals on the Honeywell aquastat on the left rear of the unit. If not, as Rob said, it is running on the low limit for control. If it is not jumpered, please do so. No voltage issues, it is a dry contact. I heard that you may have a pressure reduction feed that is not working well, and allows extra water in very slowly (city pressure, not boiler pressure) and that is increasing the pressure in the boiler. I also heard that you are going to install an Amtrol 40X floor mount expansion tank. The only way to prevent the pressure increase is to shut off the feed valve to the boiler. and remove a little water to keep the pressure down to the 18 psi range. Back to the aquastat, I would suggest an increase to 185 and the diff of 10 degrees. The only thing you will want to keep an eye on is the pressure until the feed gets updated. I'd go back to 4.5 and 4.5 with the higher temp setting on the aquastat. You said there was a 2" ring and that is now gone, so you need to backtrack a little. Any idea about the coal you use? Rice I assume, but any idea who if comes from in PA? It sounds like the temp of the water circulating is the issue.
Change as few parameters as you can at one time, and make notes about what, when, and how much.