KA6 Coking up in the Grates

The flapper on the bottom. The shutter on the small blower that runs all the time should be about 1/2 open...give or take.

That's where it's been set all along. I'm really scratching my head with this. Until I figure it out or it warms up outside I have to break that clump every few hours.

The small blower has little effect on the fire when stoking, it is just to keep the coal burning between timer cycles. The main air flap adjusts the combustion air during stoking.

Post a picture of the fire when the stoker is working.

See how high the coal was building above the sides? And that's minimal. If I don't push it down it will look like I didn't empty ashes. .... it's been 3 inches over the sides before I've caught it before. As you can see in the one pic I have the flapper a bit less than half and usually do. This thing works perfect until it's near zero outside and then it runs allot and starts doing this.

What is the feed set at?

I tried it at 5 and 6 and it made no difference. ...I ran out of the 180 pounds of buck I bought to try so now it's back to the rice I have. I got great heat out of the buck..... better than the rice I have. .... Not sure what I want to do. I used 180 pounds of buck from 4pm yesterday to 8am today. Id use maybe a bit less with rice. I'm heating a huge house and half of it's not insulated. .... old Victorian. I'd like to stick with rice because my customers I plow for like how I mix my ash with my salt for cinders. ... plus it gets rid of my ash.

You have the feed set well beyond Keystoker's recommendation, and it is still struggling...I hate to be the bearer or bad news, but it sounds like your boiler is undersized.

I think you didn't understand my post. With buck I was at 5 or 6 turns as the manual states. With rice I'm between 10-12 just like the manual says. I got the manual out last night when I have the buck a trial run to make sure it was set right

Mine does that too, but it only pushes off maybe a handful of raw coal. I'm burning Blaschak - the ash cake will hang over the edge sometimes up to 6" before gravity busts it off into the ashpan.

Then sometimes the bed will go shallow, and that's usually when the CO alarm goes off. Now I just leave a paper on the combustion air intake. So far so good - house is still warm in this cold & windy single digit weather.

Whens it really cold and your pushing these, they do coke/cake up a little, cause they are burning so hot.
I'm getting a little coal cakes in my keystoker, but it's not pushing off the sides, it did one year and hit the door and made a big mess, but I added some buckwheat and it seems to solve the problem.

Try closing the silver colored air flap on the bottom all the way closed. That looks to be a very big and hot fire you have going and the high heat causes the fusion. As Rob stated you may be asking too much of your boiler for these real cold days.

My KA 6 is oversized for my house so I run it at a slightly reduced feed rate, buy my coal from Superior, and have never, ever produced a clinker bigger than about 2” and they usually fall apart if I try to pick them up.

Some coal does not form clinkers as readily as others but most of the suppliers are selling and processing coal from various sources and those sources and the blending may never be the same from day to day or week to week so someone’s good coal this month may be the worst coal next month. I would be hesitant to recommend you waste more time and money trying to track down better coal when better coal may not exist.

So I'm at a loss. We've had days in the mid 30's now and it's still doing it. Closed the air feed, adjusted draft again. Slowed the air into the combustion fan. ... even went do far as to wire wheel the grates and sides of the stoker too make sure nothing was built up for it to not slide easily. Even at super cold temps it gets hot enough to go off on its high temp setting so I don't think I'm asking too much of it. ... it did it with the buckwheat coal also but it was pretty cold out. I'm not sure what to try other than different coal again. ... ideas?

My KA6 burning Blaschak Rice has been making sheet cake sized ash cakes all winter. They hang off the end of the grate several inches, at times, before falling off into the ash pan. I've tried various feed an air settings and nothing seems to make a difference. Very little un burnt coal though. Good heat. Stoker working fine otherwise.