Upper pipe is stainless, but the lower is SCH 40 pipe. The holes in the upper pipe get clogged. I have to pull the upper pipe, and punch out the hardened fines. They do not brush out. The fines dry like soft cement in the holes. I also have to clean out the chamber above the holes to make sure its clear.
The fines dry inside the lower pot opposite the feed inlet, and it builds up into this cement like material which blocks the upward flow of coal. This causes the coal in the pot to burn uneven since the coal on the opposite side of the pot does not rise properly. I have to shut down the boiler, and chisel out the dried fines. It does not brush out since its very hard material.
Either the coal is filled with fines or something is creating fines as it feeds into the pot.
Right now, the coal is burning uneven and smoke is filling the bin. So I am 100% certain the holes are plugged again, and the pot is filled with cement like fine deposits. I'm going to shut it down this weekend and fix it again. I have done this many times now.
The bin fills with dense gray smoke. When I open the lid its filled with gray smoke which smells. This only happens when the blower run during heating cycle. It does not seem to occur during idle.
I'm going to talk to the place where I buy coal and find out if there is a way to purchase coal which is not so wet. I cover the coal with plastic when its delivered. I do let the coal sit in a 2nd bin to dry, and this helps alot. But sometimes I don't keep up with it, and have to put some less dry coal in the bin.
I thought about adding the air tube from the blower to the upper pipe so I don't have to keep pulling the upper pipe to clear the holes.