Tuning in ye old stoker strategies

Gentlee-men, first as a newcomer I'd like to say how invaluable (that means super and above value, not lacking in...) this forum has been to me quite recently.
Long and the short of it is I've replace my oil guzzler with a Ka-6 just recently and want to know some of thoughts and experience regarding the (possibly never ending) tune in procedure.
I'm a machinist so I deal a lot in measurable data, if you speak to me in such I would greatly appreciate it!

So how do you guys tune in your stokers as far as stoking/idling goes? Would you rather it always bouncing off the low limit but consistently stoking to maintain fire? Or do you live with the substantial time to ramp up to heat by using a high feed to get some idle time in between?

How are you measuring efficiency? Looking at your ashes? Feeling flue temp? Measuring draft? Following manufacturer's guidelines for bed size? Trying different coal supplies?

Keystoker recommends about a 2" bed of ash while stoking but mine is more like 3", I feel I have the feed cranked up pretty high and am a little hesitant to go more. I live in a 1400sq ft uninsulated casa and going thru over 90lbs a day (temps mid twenties during the day and high teens at night) also supplying DHW, thermostat set to 70-72, seems a little excessive (usage that is) to me from what I'm reading from other posts. Just installed and properly set barometric damper to maintain -.02 draft so I suspect I was losing some to the glorious outdoors (maybe not enough to notice). Anyway, thanks for any input!

Your coal use is not excessive with your KAA-6. You can back off the stoker to
12 threads like I have on my kaa-4-1 and have a better burn with light fluffy ash.

These units are easy to dial in. Just remember, small adjustments at a time. My KAA-4-1 has (or should have) a different burner than you, but the concepts are the same. I am heating 2000 sq feet in Western NY, 30 minutes from Erie PA. It was -1 this morning, the house is set at 67* and I’m going through about 80lbs per day right now. The house is insulated to 1970’s standards.

Start with the settings listed in the manual for your coal feed, then make one adjustment at a time to correct a specific problem you may be having.

I am set up so that I have the 2” of ash at the end of the grate after a 45 minute continuous burn. I then set the timer to hold a 1” strip of glowing coals at idle. I usually have to remove a pin or two in the summer to keep from triggering the dump zone when I’m only heating dhw. Low limit is set to come on at 155, high to 175. Fill with coal, empty the ash. Clean.

I clean my horizontal sections of chimney pipe every 6 weeks, (T’s make this easy), and I brush down the interior at the same time. Don’t forget to clean all of the passages and baffles. I find flyash buildup really affects performance.

I permanently mounted a Dwyer manometer to the front of my boiler. It makes it easy to make adjustments (no guessing) and it lets you know when something isn’t right (like when your horizontal chimney pipe section is full of flyash...)

lzaharis wrote: ↑

Sun. Feb. 21, 2021 9:48 pm

Your coal use is not excessive with your KAA-6. You can back off the stoker to
12 threads like I have on my kaa-4-1 and have a better burn with light fluffy ash.

Please note:
There has never ever been a model KAA-6 in existence.
Only the KA-6 and it's stoker is vastly different than your KAA-4 stoker...2 different patents even.

Retro_Origin wrote: ↑

Sun. Feb. 21, 2021 7:59 pm

Gentlee-men, first as a newcomer I'd like to say how invaluable (that means super and above value, not lacking in...) this forum has been to me quite recently.
Long and the short of it is I've replace my oil guzzler with a Ka-6 just recently and want to know some of thoughts and experience regarding the (possibly never ending) tune in procedure.
I'm a machinist so I deal a lot in measurable data, if you speak to me in such I would greatly appreciate it!

So how do you guys tune in your stokers as far as stoking/idling goes? Would you rather it always bouncing off the low limit but consistently stoking to maintain fire? Or do you live with the substantial time to ramp up to heat by using a high feed to get some idle time in between?

How are you measuring efficiency? Looking at your ashes? Feeling flue temp? Measuring draft? Following manufacturer's guidelines for bed size? Trying different coal supplies?

Keystoker recommends about a 2" bed of ash while stoking but mine is more like 3", I feel I have the feed cranked up pretty high and am a little hesitant to go more. I live in a 1400sq ft uninsulated casa and going thru over 90lbs a day (temps mid twenties during the day and high teens at night) also supplying DHW, thermostat set to 70-72, seems a little excessive (usage that is) to me from what I'm reading from other posts. Just installed and properly set barometric damper to maintain -.02 draft so I suspect I was losing some to the glorious outdoors (maybe not enough to notice). Anyway, thanks for any input!

This was put together by a fellow member: Keystoker KA-6 Operation Guide.

McGiever wrote: ↑

Mon. Feb. 22, 2021 4:39 am

Please note:
There has never ever been a model KAA-6 in existence.
Only the KA-6 and it's stoker is vastly different than your KAA-4 stoker...2 different patents even.

Not trying to be a smart ass here, but I suspect some K-6 units are equipped with the flat grate nylon cam burner. When Keystone finally sent me the right manual for my boiler, it is listed as being for “K-2, K-4, and K-6 flat grate with a 6 Inch Stack”.

I have also stumbled on a YouTube video with a guy running a K-6 with a direct vent, and it had the flat grate burner.

Regardless, both burners are adjusted to have a similar burn pattern on the grate.

P.johnson14 wrote: ↑

Mon. Feb. 22, 2021 5:29 am

Not trying to be a smart ass here, but I suspect some K-6 units are equipped with the flat grate nylon cam burner. When Keystone finally sent me the right manual for my boiler, it is listed as being for “K-2, K-4, and K-6 flat grate with a 6 Inch Stack”.

I have also stumbled on a YouTube video with a guy running a K-6 with a direct vent, and it had the flat grate burner.

Regardless, both burners are adjusted to have a similar burn pattern on the grate.

LOL! The terminology is getting ppl mixed up, so it seems.

KA-6, KFL-6, K-6...3 models, 2nd and 3rd are flat grate nylon cam burner...1st is not.

There is the battleship full size KA-6 w/ "A" size burner
Then the newest one a KFL-6 w/ ..."AA" size burner...???
Then the K-2 and K-6 which both have 6" stack...can direct-vent and have "AA" size burner, it's what you must of seen on YouTube.
If yours is a K-6 w/ a 6" stack and flat grate nylon cam burner then it is "AA" size burner same as those direct-vent models.
Then there is also the smallest model KAA-2 w/ "AA" size burner also.

Thanks for all your replies!

McGiever wrote: ↑

Mon. Feb. 22, 2021 4:49 am

This was put together by a fellow member: Keystoker KA-6 Operation Guide.

I have read this multiple times but I was left unsure about the function of the shutter, is it a primary adjustment for draft before the baro? Are you guys fiddling with it based on your flames to achieve "proper burn"? I also was confused by instructions on the red nut adjustment, in the manual it says "When this RED nut is in highest position toward
boiler there is no lost motion on drive rod. Stoker is now at full coal feed." where as in the writeup it shows the opposite...

My nut was at 9 turns from full but I still wasn't getting the 2" of ash, more like 3", although it was really cranking thru the coal!
However just noticed my timer isn't working...(this was hooked up a week ago, the plumber asked me if the timer was working and I did think I saw it tick...anywho it worked before he fiddled the wiring so turns out looks like he might have hooked up backwards!) so it is working now- do you think it's possible that since I was only running when the aquastat was calling the whole boiler was getting a chance to cool down too much? (it drops to like 140 before it starts the positive turn around, set at 165 ) Are you guys relying on the timer during the winter to keep near operating temp prior to heat calls?

Also my bed is pretty thick (burning buck) it comes very close to the height of the sides...you know what hang it all, here's a picture, this is after about 15 minutes of stoking, sorry for the bad quality...it's from an ipad because i have a fleep phone.

Read Rob's post again and then another time as well.
Step one is firing rate enough to maintain house temperature. In coldest temperature with about half the time running.

Close down air supply some and back off feed until you get that 2 inch ash. Right now the feed is struggling to keep up with too much air. The air determines the firing rate and the feed is adjustable to match that firing rate properly. Firing rate now or air supply is way too much

Stack temperature will fall and so will consumption.

An oil burner analogy would be if I opened the air shutter all the way and then kept putting in larger nozzles to keep up with the air to get a proper fire.

That feed is a little much. My Keystoker90 with the flat plate got out of adjustment over time as I would see the counterweight on the threaded shaft turned and would just rotate it clockwise to straighten it and over time my feed rate was too much and I even pushed fresh coal over the sides. Now mine is backed off and the bed is a bit shallower and the 2 inches of ash at the end of the grate is not as deep as well.

Thanks guys, I really appreciate your input. That should be sufficient to get things squared away! I was disregarding the airflow as being so influential on the burn rate.

franco b wrote: ↑

Mon. Feb. 22, 2021 10:48 pm

Read Rob's post again and then another time as well.

I love this, haha if I had a dollar for everytimeI was told to re-read something... good comparison with the oil burner too.

Welcome to the group!

I also have KA-6 with a mix of baseboard and radiators.

Using indirect DHW (tank with internal heat exchanger and separate zone)

What are you using for distribution? Baseboards' output carries dramatically with water temp.

When it is cold, I adjust aquastat to 165 low, 180 high. Remember 140F is minimum safe temp for condensation and baseboard doesn't work effectively below 160F or so.

Do you have a manometer? You'll want one to dial in the draft using baro and your fan openings. I use .015

My continuous fan (little one stick to the back of the feed area) is most of the way closed.

They are really sensitive to input blower air. Too much and you get a "cold fire" which burns coal but the boiler doesn't get much heat.

Those individual pieces of ash that look like burnt coal are a sign of to much air. It should just start to cake together.

What size and brand of coal are you using? Air is different for different sizes and even brands.

Our house isn't well insulated everywhere as we remodel, so we keep our fire at a hotter standby.

If you need help with wiring or whatever, I have a thread with some pics somewhere.

CoalisCoolxWarm wrote: ↑

Wed. Feb. 24, 2021 11:58 am

Welcome to the group!

I also have KA-6 with a mix of baseboard and radiators.

Using indirect DHW (tank with internal heat exchanger and separate zone)

What are you using for distribution? Baseboards' output carries dramatically with water temp.

When it is cold, I adjust aquastat to 165 low, 180 high. Remember 140F is minimum safe temp for condensation and baseboard doesn't work effectively below 160F or so.

Do you have a manometer? You'll want one to dial in the draft using baro and your fan openings. I use .015

My continuous fan (little one stick to the back of the feed area) is most of the way closed.

They are really sensitive to input blower air. Too much and you get a "cold fire" which burns coal but the boiler doesn't get much heat.

Those individual pieces of ash that look like burnt coal are a sign of to much air. It should just start to cake together.

What size and brand of coal are you using? Air is different for different sizes and even brands.

Our house isn't well insulated everywhere as we remodel, so we keep our fire at a hotter standby.

If you need help with wiring or whatever, I have a thread with some pics somewhere.

I was initially using buckwheat but with the shutter almost all the way closed and secondary blower only open slightly I was getting a (relatively) hot fire, blinding actually. I talked a to friend of mine and he told me to go to rice because he had the same issue with his KA-6, I bought a couple of bags of rice and had a nice steady blue flame and it really heated the boiler up quickly. The install guy didn't tie in the circ/t-stat to the aquastat and instead used a zone control (I think??)(I have a backup oil guzzler and I think that's why)...anyway the circ/t-stat ran independent of the boiler...which was really bad and dropping my temp too low to recoop. (yes, have finned baseboards too) I wired everything thru the boiler aquastat and it helped drastically. I'm using coal from superior in Valley View and it does seem to be decent. (I've read that Superior can size a little bigger than others, which would explain why my friend and I seemed to have issues with the buck) Although I've been told Blashak (spelling?) up in Mahonoy city (ironic title) is some real good stuff. I used a draft gauge to set it between .01-.02 with a damper. Put in a heatilator (after the damper due to my setup didn't have much choice till I do a full shutdown and clean the pipes I'll swap it with the damper) and the heat slips right by it, I suspected a broken thermodisc in the unit and just directly wired it, and even when the stack is too hot to touch I'm lucky to get 90deg air coming out. Seems like it idles really nice with buck but as soon as the main blower kicks on that heat is just blown out, I could barely feel heat from the firedoor opening. I went and got another load of 'rice' just yesterday but it ended up being almost the same size as the buck I had got! (ultra oversized if you ask me)

I noticed a couple of things in your post that may help.

1. Heatilator is NOT necessary on KA6, in fact it may be bad for your chimney and draft because...

2. Stovepipe after barometric damper should easily be cool enough to touch. I can hold my hand there all day. (I watch my woodburner buddies turn green when they consider how much heat is NOT going up the chimney, LOL)

This further reinforces my earlier opinion that you have too much air blowing into your stoker bed. If your stovepipe is too hot to keep your hand on it, there is too much heat going up the chimney.

My full-time fan (the small one hanging off the rear) is BARELY open, just a sliver. My blower motor is open further, but not by much.

I'm on a medical thing at the moment, but I will be checking the ashes later today and will snap a few pics for you.

Anything else you want to see?