Keystoker KA-6 feed

I just installed a Ka-6 with direct vent yesterday. It is hooked in parallel with my oil burner. Hi - 180, Low 165. Last evening after firing it up, I had 2 inches of ash, 3-4 inches of glowing coal, and 3-4 inches of unburnt coal. The coal was about half way up the sides of the grate (approx 1 inch deep of glowing coal) I checked it in the middle of the night and this morning and there is about an inch of over hanging clinked up ashes hanging off of the end of the grate. The coal is now about a half inch to inch over the top of the grate (probably 3-4 inches think). It is that thick at the feed end of the grate that coal is falling off the sides of the grate. I assume the clinked up coal hanging from the end of the grate is holding up the flow of the coal and making a build up of the burning and unburnt coal on the grate.

What is causing the clinking of the ash and making the burnt and unburnt coal to build up.

Let me know if you need any other information.

The ashes that are fused together are called "clinkers". This happens when your coal burns really hot. I sometimes have 3-4 inches hanging off the end before it breaks off and falls into the tub. When this happens my coal spills over the side of the grates also. It's marginal...maybe a handfull every couple of days. I just take my small stove shovel and put it back in the hopper. This usually only happens when it's really cold out. I don't ever remember it being 3-4 inches thick before it reaches the air holes on the grates.....maybe 2 inches. You have a direct vent model. It has a different stoker mechanism than the regular K6. So, I don't know much about setting your model. I think you have the same stoker as the K2. Hopefully someone who has a direct vent K6 will chime in to help you. Good luck.

Bob

I am not sure that I do have a different stoker than the normal K6. It looks the same as all ther pictures on here. I bought the unit used. The man had it hooked up via direct vent originally, but then built a chimney and switched to that. Anyone have pictures of the different stokers?

I might have exagerated a little bit when I said 4 inches, but it was definately "mounded" up a little higher than the edges. I had it set at 10 turns out, but changed it to 12 turns this morning and it seems to be doing a whole lot better. We are home today and wife is running the washer and dish washer, so there isn't much idle time on it.

I do not have any pegs in the timer as I watched it all evening and it never came close to going out while on idle time. Do you think putting a peg or two in would help?

Well, since it was converted back to normal, you must have the same stoker as I do. I think it was a good idea to turn it down to 12 turns. 10 turns is quite a bit. Mine is at 13 turns. You'll notice a big difference now. Just remember, if you make adjustments....make small ones. Just one turn up or down on the red nut makes a huge difference. As far as putting pins in the timer......it all depends on the need for heat or DHW. If you have plenty of demand for both, you won't need any pins. With the current temps and winds around here, my demand is pretty high. This morning I had 4 of my 5 zones calling for heat at the same time. I still have 3 pins every 15 minutes since October. The heat isn't lost. I hope someone with a direct vent K6 chimes in and shows a pic. Here's a pic of of my K6.

Sometimes excess combustion air can cause the high burning temps resulting in clinkers.. if your combustion fan has a flapper for the opening, it usually is at about 1/2 open, try closing it a very little bit at a time.. and see if the clinkers get softer or go away.. As long as you still have ashes at the end of the grate, and not hot coals, you have enough air for the feed rate..

Greg L

Sometimes the grate is really rough, has a rusty surface, or fused-on ash.. you might try scraping the surface of the grate with a stiff putty knife to see if it's smooth, if not, you might need to shut down and sand the grate smooth.

GL

I have been watching it the past 4 hours and it seems to be doing pretty good since I moved it to 12 turns. At the end of a heating cycle, I have around 3 inches of ash/clinkers. Do you think I should move it up a turn to 11 or let it go overnight to see how it does.

Also, this thing didn't come with a manual on the timer and Keystoker doesn't have anything on their website, but when you say you have 3 pins every 15 minutes, does that mean you have 1 pin on the 5 min, 10 min, and 15 min mark?

Unless the clinker is against something it should not be affecting the flow of coal and ash down the grate. The ashes must be able to freely fall into the ash tub. Some type of obstruction or speed bump is the most likely cause of coal backing up and not freely flowing down the grate. Make sure the grate surface is smooth, some foreign material in with your coal or maybe some coal high in iron could have fused itself to the grate I suppose. The coal bed should be pretty even in depth going down the grate and should not be mounding up and overflowing.

OK, I took the dog on a walk before I submitted this and I see Greg L beat me to it so the above is a bit redundant.

3 pins in a row every 15 minutes or ~45 seconds of continuous run time followed by 14 minutes and 15 seconds idle time would be typical.

I think Keystoker specs about an inch or two dead ash at the bottom of the grate when running full fire. If burning coal is falling off the grate you are overfeeding or trying to ask it to make more heat than it was designed to. It is OK to have 3 or 4 inches of dead ash while running continuously if the KA-6 is larger than you need.

Ditto others on too much combustion air = clinker. If I give mine too much air, it'll make a solid clinker that'll stick straight out out past the bed and actually butt up against the baffle in the boiler [Kaa-2].

http://keystoker.com/service-manuals.php

Dave

1 pin = 15 seconds of stoker time. So 3 pins = 45 seconds. etc...Put 3 pins at the 0 and 15 min. markings, if you have a 30 min timer.
Also, make sure your baro damper/draft is set correctly with draft gauge. That can draw too much air thru the coals and cause the clinkers to form, but looks like you are the right track....

These guys know what they are talking about! I haven't had time to post again til now. Just follow their advise and everything will be fine.

Seems to be running great since I moved it out to 12 turns yesterday afternoon. The only thing is the clinkers. There are still lots of them. I break them apart and there isn't any unburnt coal in them. You said they come from burning the coal at high temps. Does it hurt to have them? Is the stove running less efficient if they are there?

Thanks again for your help and advice. It is pretty nice having a 72 degree home rather than a 66 degree home.

On my Keystoker 90K, I had a clinker/ash bridge that formed and pushed all the way across to the door, and backed everything up inside the stove and made a real mess! Have you check the draft or adjusted the combustion blower. Some blowers have a cover over the inlet of the blower, and should be set correctly.

Skeeter41 wrote:Seems to be running great since I moved it out to 12 turns yesterday afternoon. The only thing is the clinkers. There are still lots of them. I break them apart and there isn't any unburnt coal in them. You said they come from burning the coal at high temps. Does it hurt to have them? Is the stove running less efficient if they are there?

Thanks again for your help and advice. It is pretty nice having a 72 degree home rather than a 66 degree home.

Skeeter,

Mine forms a smooth bottom clinker, molded to the bed's shape if I run it too hot [too much air]. I'm a semi novice, but it seems to me that the air holes in the bed may not stay as clean with a sold clinker forming. When mine is burning nicely [proper air], it seems to me that the air getting through the ash tends to help keep the crap out of the air holes.

Dave

I have an old stoker and I only have this problem when I burn Harmony coal. I have used other coal and never experienced what your describing When the temps moderate (above 30) I can back off the air and I still get the clinkers forming but they don't fuse completely solid. When I first switched to Harmony I had exactly what you described. Solid clinkers that stayed together and pushed all the way off the end of the grate till they hit the stove front. Then the new coal would just back up and pile up until it spilled over the sides of the grate. The red ash seems to clinker up due to high iron content. It's a matter of air adjustment. The clinkers won't hurt anything but they can be annoying.