Keystoker K6 Issues

 
Buckshot1822
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Post by Buckshot1822 » Thu. Nov. 09, 2017 7:37 am

I have a Keystoker K6 that I installed last year. Last winter I used it to heat a whole house addition, with around 50' of fin tube baseboard on 3 separate zones. It ran fine all winter, with typical coal consumption that I would expect. I recently added 2 new zones in the original part of my home. There is 19' of fin tube, and a 8x12x36" cast iron radiator on 2 separate zones. These zones are fairly high demand though due to poor insulation in that part of the home. Ever since I turned those zones on, I am burning a full grate of coal, and even pushing fire into the ash pan. The boiler is running enough that it is filling an ash pan clear to the top pus every day. I had the feed turned down to 6 turns out overnight, and it still filled the ash pan. Obviously the boiler is running a lot more with the addition of those 2 zones. I am not sure if I can get the feed turned down enough so that I get dead ash on the end of the grate. I am now 5 turns out, and wont get a chance to check it until this evening. But, I suspect it will still fill an ash pan. Any other ideas? Maybe changing aquastat setting will help. I also have it wired to a tork timer, that right nw is set to run 30 seconds every 30 minutes. Im not 100% sure what my aquastat settings are but I can look tonight, If I had to guess they are around 150 and 180. Any advice or help will be appreciated.


 
Qtown1835
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Post by Qtown1835 » Thu. Nov. 09, 2017 7:55 am

Try running it at 10 turns. At 5 turns, im surprised you have any coal left in the hopper after a day. (You are turning the knob the wrong way) #beentheredonethat

 
Buckshot1822
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Post by Buckshot1822 » Thu. Nov. 09, 2017 8:05 am

Yep I'm pretty sure you are right, I was 9 out so I probably need to go to 11 or 12 out.

The pic in this thread is what screwed me up.

Keystoker KA-6 Operation Guide.

 
Qtown1835
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Post by Qtown1835 » Thu. Nov. 09, 2017 8:10 am

Buckshot1822 wrote:
Thu. Nov. 09, 2017 8:05 am
Yep I'm pretty sure you are right, I was 9 out so I probably need to go to 11 or 12 out.

The pic in this thread is what screwed me up.

Keystoker KA-6 Operation Guide.

I did the same thing. :)

Im currently running my K4 at 14 turns and its doing fine.

You may need to adjust your timer. 30sec every 30min usually will not hold a fire unless you have a fierce draft. I have mine at 2pins every 7.5min, basically 4 sets of 2 pins spaced equally and it has been holding well. Everyones boiler is a little different though.

 
Pacowy
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Post by Pacowy » Thu. Nov. 09, 2017 8:24 am

Have you tried opening the air shutter/main combustion air setting/"big blower air intake" somewhat? If you have added load it might be better to add the air needed to support more feed, rather than cut the feed to match limited air.

Mike

 
Buckshot1822
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Post by Buckshot1822 » Thu. Nov. 09, 2017 9:04 am

Sorry I misspoke with the timer, it's 3 minutes every 30 minutes, and it seems to hold a fire fine except for the warmest days. I usually change it once it gets to that point. I did open the air shutter more also. But I was feeding way to much coal. I had an Ash pan full of burning coal last night before I changed any settings

 
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oliver power
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Post by oliver power » Thu. Nov. 09, 2017 8:58 pm

I have to ask; Are you dumping excess heat? With a full grate of burning coals, is it triggering your dump zone.

By adding more load, it may be drawing down the boiler too quick. Triple Aquastat starts pushing the coal, trying to recover. Next thing you know, the grate is full of fire.

If this is the case, here's what you need to do: You need a bigger idle fire, in order to reduce lag time. That's where I would have started before lessening my feed. If the boiler ran fine all last year, you should have left the feed alone. Common sense says, if anything, you need to add feed, not lessen it. The added draw on the boiler is pulling the boiler down too far, before it had a chance to catch up. A bigger idle fire will take care of that. The bigger idle fire will lessen the lag time, giving the boiler a chance to catch up.

This is what I had to do with my Kaa-2. I ended up cutting back my feed, and maintaining a little bigger idle fire. My Kaa-2 purrs along flawlessly.

By the way; did you clean the inside of boiler since last year. Don't forget around, and in-between the water wall baffles.
Last edited by oliver power on Thu. Nov. 09, 2017 9:46 pm, edited 1 time in total.


 
Buckshot1822
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Post by Buckshot1822 » Thu. Nov. 09, 2017 9:22 pm

I backed the feed off and it seems fine. I'm pretty much positive the whole issue stems from the fact that the boiler is running more often due to the additional demand. It didn't have much demand last year due to great insulation in the addition. So, adding the more demanding small zones required the boiler to run more often, causing the same feed rate to overload the grate.

 
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oliver power
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Post by oliver power » Thu. Nov. 09, 2017 10:52 pm

Buckshot1822 wrote:
Thu. Nov. 09, 2017 9:22 pm
I backed the feed off and it seems fine. I'm pretty much positive the whole issue stems from the fact that the boiler is running more often due to the additional demand. It didn't have much demand last year due to great insulation in the addition. So, adding the more demanding small zones required the boiler to run more often, causing the same feed rate to overload the grate.
So, in other words, if I'm thinking correctly, last year you heated your house with the reserve capacity of the boiler. All the boiler had to do was maintain it's own water temp. Triple Aquastat controlled the boiler temp. Stroke of stoker didn't matter, as long as you didn't draw the boiler itself down too far.

This year, with the added draw, you are not able to heat your house using only the reserve capacity of the boiler itself. Because the current load is pulling the boiler down, the Triple Aquastat is telling the stoker to shovel on more coal, in order to bring the boiler temp back up. And of course, with too much stroke, the grate is full by the time the triple aquastat is satisfied. So you shortened the stroke, and things are working good. That's great!

Now, as the weather gets cooler, should the boiler get drawn down far enough to shut down circulator pump, you'll want to increase the size of the idle fire. You increase the size of idle fire by adding pins. Increasing the size of idle fire, decreases lag time. The bigger idle fire ignites the fresh coal being pushed on the grates, quicker, reducing lag time. No need to add a lot of pins. Only enough to give the fire a head start to the demand. You're not trying to run on the timer. Add length to stroke ONLY if over all steady state operation of boiler falls short of demand. Add length to stroke as last resort. Kind of a balancing act......
Last edited by oliver power on Fri. Nov. 10, 2017 9:18 pm, edited 4 times in total.

 
Buckshot1822
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Post by Buckshot1822 » Fri. Nov. 10, 2017 10:11 am

Yea more or less that's what is occuring I believe.

 
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Post by Pacowy » Fri. Nov. 10, 2017 11:20 am

Pardon me for interjecting with one of my pet peeves here, but it sounds like part of the problem is the shortage of burnable coal on the grate at the time there is a call for heat. AFAIK that is a byproduct of using the secondary air blower. Personally, I'd rather have my ash be a little rough and have the system respond to its controls without the time delay introduced by the fact that the blower consumed most/all of the coal on the grate, blowing those btu's up the flue, sucking additional btu's out of the boiler by blowing cooling air into the combustion chamber through the dead ash, and in the end wasting coal. End of rant. Thanks, I feel better now.

Mike

 
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Rob R.
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Post by Rob R. » Fri. Nov. 10, 2017 12:42 pm

My $0.02 is that you never properly adjusted the fire for steady-state operation last year. Unless you put enough load on the boiler for it to run the stoker continuously for 30+ minutes before making your adjustments, you are making adjustments based on an immature fire.

To Mike's point, the excess coal you were feeding last year was probably getting burned by the secondary blower while the boiler sat idle.

 
Pacowy
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Post by Pacowy » Fri. Nov. 10, 2017 1:11 pm

Rob R. wrote:
Fri. Nov. 10, 2017 12:42 pm
My $0.02 is that you never properly adjusted the fire for steady-state operation last year. Unless you put enough load on the boiler for it to run the stoker continuously for 30+ minutes before making your adjustments, you are making adjustments based on an immature fire.
x2. The stoker shouldn't start putting burning coals in the ash pan just because it is used more. My rant was mainly provoked by oliver p's observations, but the fundamental fuel/air mix issue raised by Rob is probably even a bigger factor affecting overall efficiency. And perhaps there is even an overlap between the two in that a stoker with a secondary blower may take even longer than 30 minutes to get to the steady-state operation needed to assess the fuel-air mix.

Mike

 
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gaw
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Post by gaw » Fri. Nov. 10, 2017 1:15 pm

You do have a bypass loop?

 
Buckshot1822
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Post by Buckshot1822 » Fri. Nov. 10, 2017 1:24 pm

Yes I have a bypass loop. Not at all related to the secondary blower. I don't even have the secondary blower installed. The whole issue was more demand was causing the boiler to run more often, could be almost twice as often I'm guessing. I ran a little higher feed rate last year than I probably needed to anyways. But with the stoker running more often, and the high feed rate I was burning a full grate of coal, plus the fire was being pushed off of the grate into the ash pan. I have the feed backed off, and it seems fine now, I had 1.5" of dead ash at the end of the grate after it ran all night.
Last edited by Buckshot1822 on Fri. Nov. 10, 2017 1:30 pm, edited 1 time in total.


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