macdabs wrote: Could it be the Ep bender nut coal?
I was reading through your posts and found one that mentioned the coal is Bituminous. Most of us here are burning Anthracite. Bit coal has a longer learning curve than Anthracite and personally, I have no idea how it's done! I do know that it's tricky and if not done right, it's very frustrating. "Done right" means not only done correctly, but done in a proper device. My gut it telling me that your boiler, while advertised to burn coal, isn't a great coal burner. Coal stoves burn coal. Wood stoves burn wood. You can usually burn wood in a coal stove, but most combination stoves (or boilers) are not all that great at burning coal. Add that to burning Bit, and I think therein lies a lot of the problem. That being said, I'm sure there are people here that can get you burning far better than you are now. In order to do that they will need some information, such as:
Good pictures of the boiler outside and more importantly, inside, the grates, the walls, the shape. A description of the dimensions of the firebox.
Description of the chimney, type, size, height.
Does it have a barometric damper?
Does it have a Manometer?
What controls the incoming air, and does the air come in over or under the coal? Or both?