Feed rate

Hi, I've been playing around with my feed rate this winter. I have the Keystoker 90, I seem to have the rate set just where it can keep up and keep the upstairs at 70 degrees (until it gets bitter cold). Is this the best way to have it set to use the least amount of coal? I have the feed screw turned out 8 turns, and added 2 extra pins to the timer for the idle fire. It seems to work really well this way, the flames just touch the top of the stove a little when it's firing for a long time. I have about 2 to 2 1/2 inches of ash on the end of the grate at full fire. It does require the stove to be feeding coal more often and longer intervals but it seems to keep the temp upstairs incredibly constant only varying by a degree under or over 70. I figure this way the coal has a slower more even burn and will allow it to burn more effiently and completely rather than having a rip roaring fire every so often, then dying back down to idle for long periods. What are your thoughts? Oh and I have the air flap on the combustion motor set at factory 1/2 closed, and using rice coal.

Sounds like you got the hang of it! It should be noted that all automatic stokers burning anthracite will discard some unburned coal with the ashes during normal combustion. This is due to anthracite being slow burning and the timing of the feed mechanism or lack of demand for heat by the thermostat. 2.5 inches of ash is about as much as possible and assuming that ash is looking well burned then i think you got it down to a science bro!

You can have up to about 1" of ash at full burn, as long as you are not pushing hot coals off the end when it there is a long demand for heat, you should be good. I think I have mine at 4-6 turns out and works quite well.
Only adjust 1/2 turn at a time in or out depending on if you want more or less feed.
The Extra pins will get you 15 secs of stoke time per pin, so you added 30 secs per cycle on idle. Typically, if you at not having any issues with idle, then the extra pins will just increase the heat just a bit at idle

Have you had the draft checked and adjusted correctly? That will also help in maintain proper heat in the stove.

WNY wrote:You can have up to about 1" of ash at full burn, as long as you are not pushing hot coals off the end when it there is a long demand for heat, you should be good. I think I have mine at 4-6 turns out and works quite well.
Only adjust 1/2 turn at a time in or out depending on if you want more or less feed.
The Extra pins will get you 15 secs of stoke time per pin, so you added 30 secs per cycle on idle. Typically, if you at not having any issues with idle, then the extra pins will just increase the heat just a bit at idle

Have you had the draft checked and adjusted correctly? That will also help in maintain proper heat in the stove.

Yeah I have the draft at -.02. The manual says between -.02 and -.03 max. I do seem to get some clinkers but it doesn't seem to be causing any problems.

I think I have mine at -.04, mine is a direct vent. -.02-.03 is good.

Is yours a direct vent or Natural Draft chimney?

Clinkers will form every now and then, depends on the load, if it's burning HOT for extended periods you may get more, or it's really cold outside and you have a bit more draft and it pulls more air thru and makes it burn hotter. Sometimes depends on the coal. I usually just get small coal cakes/clinkers sometimes, but not very often.

Do stokers have clinker problems?

It's a chimney model, maybe what I have are cakes... They are small about 2-3 inch chunks? Are clinkers larger?

WNY wrote:I think I have mine at -.04, mine is a direct vent. -.02-.03 is good.

Is yours a direct vent or Natural Draft chimney?

Clinkers will form every now and then, depends on the load, if it's burning HOT for extended periods you may get more, or it's really cold outside and you have a bit more draft and it pulls more air thru and makes it burn hotter. Sometimes depends on the coal. I usually just get small coal cakes/clinkers sometimes, but not very often.

Do stokers have clinker problems?

So, with this frigid cold in NE PA I had to increase my feed rate to allow the stove to keep up with the cold. In doing so, I noticed I wasn't getting much more heat out of the stove (I have a magnetic therm on the side of the stove). The coal was kind of dull looking with so so flame, so I checked the draft and it was at -.02 at a full burn. I increased the draft to -.03 and the fire seemed to come alive and the stove temp went up about 100 deg! Was it a case of the fire not getting enough fresh air and burning hot enough because of the draft setting? I was keeping the draft at the min to keep the heat in the stove instead of up the chimney but in this case it seems a little more draft doesn't hurt. The side of the stove on full burn gets up to 450 deg now at -.03, and at -.02 it was hanging at 350 ish.

Keeping the draft correct, will keep more heat in the stove. I have had my keystoker up to 450-500 degrees at times.
I keep mine at -.04

Also, depending on yoru Combustion air setting flap on the blower, you can sometimes open it up a little bit to give it some more air, you may be clinkers cause it may burn a bit hotter.

But, always keep an eye on your draft when making adjustments.

yeah, coal cakes/clinkers, approx. same thing. I have gotten a few the past couple days, since it's been below zero.

So, it's basically like a gasoline engine where if you have a restrictive exhaust you lose power but in this case you restrict the fire and heat. Too much draft and you suck the heat up the chimney and lose stove temp. I have the combustion flap at factory setting of half open, feed screw at 4.5 turns out and draft at -.03 at a full burn.

My KEYSTOKER Kaa-2 boiler shares the same stoker as one of the KEYSTOKER stoves. I believe it is the KEYSTOKER 90 as you have. Not positive without looking. Anyways, while reading your post, I too thought you had things down to a science. That was untill reading down the page further, when you said you increased draft. I'd stay at factory draft recommendations. Your thinking on the stoker operation is in my opinion, correct. The slower the coal travels accross the grate, the more it has time to burn. 2 - 2-1/2 inches of ash is a lot at full fire. Hey, if it does the job, that's what counts. I like KEYSTOKER's recommendation of one inch of ash at full fire. Then again, I have a boiler, which stores the heat. When I need more heat, I add pins. Still a slow push accross grates, but more pushes = more coal on grates. My opinion would be to add more pins, not stroke. And leave the draft at factory recommendations, which I see you're still within range.

I usually adjust the feed rate accordingly to the outside temperatures. I increased my draft for the recent cold spell and noticed a hotter fire. When the windchill went below 0 my living room floor only reached 66 and bedrooms got as low as 60. Had to use some oil Need to get my butt in gear and cut out some more returns and get some better ducting. Probably get some insulation blown in the walls too. Rambling on....

oliver power wrote:My KEYSTOKER Kaa-2 boiler shares the same stoker as one of the KEYSTOKER stoves. I believe it is the KEYSTOKER 90 as you have. Not positive without looking. Anyways, while reading your post, I too thought you had things down to a science. That was untill reading down the page further, when you said you increased draft. I'd stay at factory draft recommendations. Your thinking on the stoker operation is in my opinion, correct. The slower the coal travels accross the grate, the more it has time to burn. 2 - 2-1/2 inches of ash is a lot at full fire. Hey, if it does the job, that's what counts. I like KEYSTOKER's recommendation of one inch of ash at full fire. Then again, I have a boiler, which stores the heat. When I need more heat, I add pins. Still a slow push accross grates, but more pushes = more coal on grates. My opinion would be to add more pins, not stroke. And leave the draft at factory recommendations, which I see you're still within range.

During the cold spell I had to increase the feed (back to the 4 turns out factory setting) in order for the stove to make enough heat to keep up since it's downstairs. I adjusted the draft to -.03 at full burn and saw a 100 deg increase just from the draft. On my stoker adding pins only affects the idle fire, the only way to increase feed during call for heat is the feed screw. After increasing the feed and draft I had a stove temp of about 475 with an inch of ash on the grate. I will probably just leave the settings where they are now, it does overshoot the temp upstairs by 2 deg like this (when not frigid outside) but that's ok the wife likes it haha.