KA-6 Ashes, feed and air settings

Here's an official thread to answer a few questions I brought up on another thread here.

Basically, I switched to Blaschak coal (rice) this summer since I ran out of some local junk. I've had unburnt (or maybe bone/shale?)since switching even with great results as far as heat production and coal/ash ratio. (currently I get over 200lbs to fill a bushel ash tub! )

So I've been really happy with everything, but in my quest to fine tune and monitor things I installed an analog clock in series with my circulator, this way I would know how much time the circulator ran per day and could calculate my consumption.
Initially I was doing some time travel with the clock but once I plugged it into a surge protector it stabilized. (I think the on/off cycling was throwing it for a loop). Some of you are probably cringing that I wired this clock in this way...but it's working (any safety concerns I'm all ears!)

I am against the idea of just weighing out how much coal I put into the hopper because that gives me no read on how much heat I'm gaining from it, I know the circulator won't run unless the boiler is to temp. So here's my findings: (this is disregarding domestic usage, but since that usage is fairly consistent from day to day I don't see it affecting it enough to matter). I also noticed my boiler temp is usually right on 170 during circulating and since the boiler never shuts off until the heat call is done I'm not getting bad results there. (ie 1 hr of circulation at 180deg will surely burn more than 1 hr at 170)

These numbers have been double checked a few times and over a minimum of 24 hours so I feel pretty confident with the numbers. Draft maintained -.015 to -.020

Initial boiler settings: (timer never changed, so that is excluded)

As per manual start point:

1.
Feed: 14 turns
Air shutter: Half open
Idle air: Quarter open (any more than this and the fire would die during idle without a heat call over a few hours)
Result: 20 lbs to run circulator for 1 hour.

2.
Feed: 14 turns
Air shutter: Fully open
Idle air: Quarter open (any more than this and the fire would die during idle without a heat call over a few hours)
Result: 17.5 lbs to run circulator for 1 hour.

3.
Feed: 14 turns
Air shutter: Fully open
Idle air: Wired in series with main and fully open
Result: 14.5 lbs to run circulator for 1 hour.

4.
Dropped throat plate to maximum lowest position to try to thin the fire and feed harder since unburnt still present.
Feed: 13 turns
Air shutter: Fully open + some (backed screw out and moved shutter out of way a little more) (see image)
Idle air: Wired in series with main and fully open
Result: 12.5-13.5 lbs to run circulator for 1 hour.

This last test is a little inconsistent because due to the throat plate being so low sometimes the bed gets kind of 'rolled up' on itself I think because it's pushing through a smaller opening: This is a very poor representation of what my fire bed normally looks like, I'd say it's pretty much the worst case scenario.

I still haven't cleaned the boiler wet walls on purpose to see how much that will affect things once done. I'm pretty happy with the results I've had, I'm a little irritated that keystoker doesn't mention anything about any adjustment of those things. Still having some unburnt/bone/shale (whatever it is!!) in the ash as you can see.

Next I will probably raise the throat plate back up and leave the feed at 13 to see what happens. I'm used to using VERY quantified data in any sort of testing but since this is a little less quantifiable I'm trying some things somewhat blindly (ie, in theory a lower throat plate should make my bed thinner, but in the case it's making it more inconsistent I might need to undo what only works in theory)

My apologies for the sideways pictures, I rotated them and saved them on my computer but they still come in the same orientation!

The circulator runs when there is a call for heat by the thermostat, right?

Is your whole house 1 zone?

1 zone. Circulator will not run if boiler not to temp.

I understand that.. but does the circulator toggle on and off as the thermostat calls for heat to push water thru your radiators, Or are you using zone valves?

What is your method for arriving at X pounds per hour of circulator run time?

I think the way you are tracking the amount of coal burned compared to circulator time is misleading...but maybe I just need to think about it more.

I think we're on the same page Rob. Circulator run time doesn't account for coal consumed for standby loss, DHW and just maintaining the fire. Yet from what I understand he's counting all coal going in.

If standby loss helps heat the house that's a double whammy on circulator run time.

Lightning wrote: ↑

Fri. Dec. 24, 2021 2:11 pm

I understand that.. but does the circulator toggle on and off as the thermostat calls for heat to push water thru your radiators, Or are you using zone valves?

What is your method for arriving at X pounds per hour of circulator run time?

No zone valves, the Thermostat is an old mercury style so it's not doing anything beyond closing the switch on the triple aquastat. When it calls for heat, the stoker will run and the circulator will also run as long as the temp is at the high limit -diff or however that works (you guys know better than me) but when it gets down closer to the low it will stop. This happens within a minute or two of initial heat call unless the boiler just ran (a lot). Then after a while when the fire is nice and hot the circulator can constantly run because the heat generation actually can keep up with the loss from circulation. Circulator does pulse a few times until the fire gets mature, but since these are a only a few minutes each and I usually get 4-5 hours on a cold night I figure these are fairly negligible values.

Math is: Total Circ time / coal added. I have checked all numbers twice or more to ensure accuracy. I never solve unless I have at least 8 hrs....for obvious reasons! Since there's just my wife and I using domestic water for showers and dishwasher I can count on those items being pretty constant on the daily. Through the summer my usage was 15-20 lbs for domestic and now I'm averaging at least 80lbs in a day.

The point could be made that this is too simple of a math equation, but I'm trying to measure the amount of heat I get in my house from the amount of coal I burn, basically to determine whether adjustments made are positive or negative, not BTU calc or anything.

Your thoughts and corrections appreciated.

Anyway, Merry Christmas to all, and here's some other "not to be forgotten" form of black energy:

Perhaps factor in outside temps and keep inside tstat fixed.

At least we can get a ratio of lbs coal used related to BTUs needed (loose correlation to outside temp)

Right now we don't know the heat load, but we can get closer by knowing there is *some * relation to outside temp, even if we don't know it and it isn't exactly precise.

It should be closer to accurate for his house. Might not apply to another house with different heat losses, which are not usually linear.

Interesting experiment, though

If the intent is "to determine whether changes made are positive or negative", I don't understand why the computations ignore the guidance Keystoker and other mfgrs provide regarding the width of the ash band (or ring). If you know from the ash band that a given fuel/air mixture is inefficient, who cares what these numbers say about it?

Mike

The point could be made that this is too simple of a math equation, but I'm trying to measure the amount of heat I get in my house from the amount of coal I burn, basically to determine whether adjustments made are positive or negative, not BTU calc or anything.

I understand what are you are trying to do, and I think recording the circulator run time is neat- but I can tell you that using more combustion air than is needed just sends heat up the chimney. You will never remove all traces of black from the ashes, and attempting to do so usually results in more coal burned than if you had a few black specs in the ash. If the answer to burning less heating oil was to open up the air band on the burner, we would all be doing it...but that doesn't work.

If you leave your feed and air settings alone for a full season and chart the daily run time of the circulator vs. coal burned, I think you will find that the colder it is, the more efficient the system appears. example: In warm weather your circulator might only run for 15 minutes in the morning, but the boiler burns 25 lbs in 24 hours. In very cold weather your circulator might be able to run an extra hour per day without any noticeable difference in coal consumption.

My suggestion is to set everything up according to factory specs, and when the stoker has been working hard and the fire is mature - check the draft at the breech and at the firedoor, and note the amount of ash on the grate. You should have about -0.05" draft at the breech, -0.02" over the fire, and about 2" of ash at the end of the grate. Adjust baro, air shutter, and feed rate as needed to accomplish this.

If you want to burn less coal, keep the stoker tuned for proper fire appearance on the grate, keep the boiler clean, and don't run the boiler warmer than necessary to heat your house.

X2.

I would particularly emphasize that it is normal (and efficient) for there to be unburned coal in the ash, as there is unburned gasoline in the exhaust from a properly internal tuned internal combustion engine, etc. Adding air to obtain a more complete burn of coal is counterproductive if it expands the ash band beyond the specified width.

Mike

Pacowy wrote: ↑

Sat. Dec. 25, 2021 8:14 pm

If the intent is "to determine whether changes made are positive or negative", I don't understand why the computations ignore the guidance Keystoker and other mfgrs provide regarding the width of the ash band (or ring). If you know from the ash band that a given fuel/air mixture is inefficient, who cares what these numbers say about it?

Mike

Thanks Mike, I have done my best to establish the 2" of ash from end of grate during a full burn principle, this was my starting value for feed rates and why the feed rate adjustment only changes when I thinned the bed out. Maybe I'm missing something, but other than that and draft settings there appears to be little guidance. I would appreciate correction upon this point.

I would have more faith in what Keystoker provides if my experience with them was more positive. Very nice people, again, very nice. But their attitude was un-technical and very generally (not specifically) helpful. Quite honestly this whole experiment has been a challenge to my faith in Keystoker's quality and actual design integrity. I certainly could not design anything nearly to the degree they have, but the throat plate slots were cut with a torch (so there's precious consistency!), the 'adapter plate' for the secondary blower bolt holes were completely wrong and I had to do it myself, and amongst other details that seemed 'half hearted' or overpriced my faith is rather lacking. You EFM guys can set your air to '4 clicks'....huh? clicks? I got this flapper dapper thingy! It just seems on the crude side.

Rob R. wrote: ↑

Sat. Dec. 25, 2021 9:01 pm

I understand what are you are trying to do, and I think recording the circulator run time is neat- but I can tell you that using more combustion air than is needed just sends heat up the chimney. You will never remove all traces of black from the ashes, and attempting to do so usually results in more coal burned than if you had a few black specs in the ash. If the answer to burning less heating oil was to open up the air band on the burner, we would all be doing it...but that doesn't work.

If you leave your feed and air settings alone for a full season and chart the daily run time of the circulator vs. coal burned, I think you will find that the colder it is, the more efficient the system appears. example: In warm weather your circulator might only run for 15 minutes in the morning, but the boiler burns 25 lbs in 24 hours. In very cold weather your circulator might be able to run an extra hour per day without any noticeable difference in coal consumption.

My suggestion is to set everything up according to factory specs, and when the stoker has been working hard and the fire is mature - check the draft at the breech and at the firedoor, and note the amount of ash on the grate. You should have about -0.05" draft at the breech, -0.02" over the fire, and about 2" of ash at the end of the grate. Adjust baro, air shutter, and feed rate as needed to accomplish this.

If you want to burn less coal, keep the stoker tuned for proper fire appearance on the grate, keep the boiler clean, and don't run the boiler warmer than necessary to heat your house.

Thanks for those guiding principles Rob, I find more help in that than the Keystoker manual. I'll be sure to do exactly what you suggest, seriously.

Please remember gentlemen that I am entirely new to this, so things like "You will never remove all traces of black from the ashes" are maybe common sense to you but to me are unknowns and would take a stupid amount of my fiddling and experimenting to learn . And when you say "don't run the boiler warmer than necessary" I assume (please correct) you are talking about my excess air settings and not my hi/lo settings on my triple aquastat?

OVERALL, this experiment has helped me learn that the more mature a fire burns more efficiently and this happens when it's colder outside.

Thanks for you input guys!

You're welcome.

I don't agree that EFM's offer a meaningful advantage over a Keystoker KA-6 in controlling the supply of fuel and air. Indeed, the Keystoker offers a direct control over the thickness of the coal bed that is not found on EFM's (aside from potentially changing the diameter of the pot ring). I understand you have been underwhelmed by the information Keystoker has provided, but you seem to have mastered the functioning of the controls provided.

Mike

Retro , I don't know if you have a ''stack temp'' thermometer in your breach or not . But we have them in all the coal burners around here. They are cheap and really help dial in a boiler. Or ............. tell you when it needs a cleaning.

Thanks for those guiding principles Rob, I find more help in that than the Keystoker manual. I'll be sure to do exactly what you suggest, seriously.

Are you looking at the most recent manual? I have attached it so you can check.

Pages 15-16 go over the steps I described above.