coal ashes

coal ashes

PostBy: voss On: Mon Oct 23, 2006 6:06 am

Hello,
i have a question about the ashes from my keystoker. The ash seems to clump together like it is not all completely burned. Is this normal for the ash? is it poor quality coal?
also i have access to a lot of old feed bags and was wondering if anyone has went to a supplier of bulk coal and bagged there own at bulk prices.
voss
 

PostBy: red ash On: Mon Oct 23, 2006 3:32 pm

Minor "clumping" is not a problem! I burn high quality, low/red ash coal and still get some clumps! If you adjust your feed rate correctly you should not have unburnt coal falling off the end of the grate! The coal is packed fairly tight on the grate and looses over 90% of its weight as it burns. This light ash clings to itself and often retains the shape of the grate!
red ash
 

PostBy: byrdy11 On: Wed Oct 25, 2006 8:41 am

Red ash...I was wondering if you could help me. I am new to all this and have a keystoker direct vent with a honeywell thermostat. I set it for 70 degrees and it never seems to reach that temperature, and the blower isnt running continuously or anything. It reaches about 68 and holds there. When I look at the ash, it doesnt seem completely burned either, like it's running through too quickly. My manual explains how to slow down the feed by turning the 'white nut' counterclockwise a half turn and then observing the ash after that....so I did that and checked it an hour later and it had adjusted itself back to the original posisition! Is this because it's trying to burn faster to get to the set temperature??? I am confused as to why the knob (white nut) would adjust back by itself to the quicker feed rate! Any insight?
byrdy11
 
Hot Air Coal Stoker Furnace: keystoker 90
Coal Size/Type: rice

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PostBy: red ash On: Thu Oct 26, 2006 12:03 am

Byrdy11, a power vented keystoker has several variables that can have a dramatic impact on the overall efficiency of the stoker! The first line of trouble to look at is the condition of the power vent system. The exhaust motor and chamber must be cleaned at least annually. Even a small blockage of fly ash can dramatically effect combustion efficiency. The next line trouble to look at is fines under the grate. The small coal fragments that work there way under the grate must be removed at least annually. The fines will reduce the efficiency of the combustion motor and lead to less efficient coal burning on the grate above. Do you know if the stoker was properly cleaned at the end of last year? The third line of trouble to look at is draft! Draft is simply a measurement of how efficiently the stove is expelling exhaust gas to the outside. If your stoker is drafting to strong you will expel valuable heat to the outside. DV keystokers should draft between, .-02 to.-04 Do you know if the stoker was ever tested with a draft gauge after installation? I understand that these questions are not directly answering your questions but they form a base to help eliminate some of the variables. 8)
red ash
 

PostBy: Richard S. On: Thu Oct 26, 2006 6:00 am

You can expect some some clumping and unburnt coal. Also be aware that stoker ash differs from hand-fired ash. I've mentioned this before, I've burned the very same coal that was being used in a Van-Wert stoker in a Franco Belge hand-fired stove and the consistency of the ashes from the Van Wert were as usual slightly chunky. The coal from the hand fired stove was like talcum powder. Barely a speck of anyhting in it.

Having said that the clumps should not be that large and you should be able to break them up easily with your hands. Generally the faster you run it the more likely you are to get these clumps.

There's a old pamphlet here from Van Wert that bescribes how the coal will look when burnt and even metions that it may not all fully burn.

Image
Richard S.
 
Stoker Coal Boiler: Van Wert VA1200
Coal Size/Type: Buckwheat/Anthracite

thanks

PostBy: byrdy11 On: Thu Oct 26, 2006 7:27 am

Thanks to you both for getting back to me. The stove only ran for about two months last winter after it was purchased, and no, I didnt have it cleaned. The owner of the place I bought my coal from took a quick peek at it and said it probably did not need to be cleaned this year. If we get another warm spell here I will unplug it, let it cool down and will take a look. Last night I cranked the thermostat up to 75 and it got pretty warm upstairs in the house (70 degrees or so) (the stove runs on the same ductwork as my backup oil furnace). I appreciate all the advice. I should have had it cleaned.
-deb
byrdy11
 
Hot Air Coal Stoker Furnace: keystoker 90
Coal Size/Type: rice

PostBy: Richard S. On: Thu Oct 26, 2006 9:02 am

You have to clean it out at least once a year, some manufacturer's recommend on a monthly basis but that is mostly them being on the safe side. Fly ash accumulates in the exhaust pipe, at the very least you should check that. It will eventually block if you don't, how long depends on the size of pipe, the coal, how often the furnace is running....etc. Ours for example could probably go 3 years before it needs any maintenance because it is huge as far as exhaust pipes go. This would be an exception compared to most systems and we still do it on yearly basis.

If you're running your unit on a seasonal basis as most are you should completely disconnect all the exhaust pipes and thoroughly clean it at the end of the season and leave it disconnected until you're ready to fire it up. This is not only relevant for safety reasons but will extend the life of the unit and pipes.
Last edited by Richard S. on Thu Oct 26, 2006 1:41 pm, edited 1 time in total.
Richard S.
 
Stoker Coal Boiler: Van Wert VA1200
Coal Size/Type: Buckwheat/Anthracite

PostBy: WNY On: Thu Oct 26, 2006 1:20 pm

We have a keystoker90 with a direct vent also.

The standard Honeywell (round dial) type thermostats are NOT very accurate and it depends on where it is mounted in relation to your stove. There is quite a bit of lag and inaccuracy with them.

I changed mine to a LUX digital Programmable and it has about a +/- 2-3 degree swing, since the stove takes a while to increase Temp. it can drop a couple degrees before it can catch up (I am Looking at the CoalTrol for better control!)

The Set Screw on the feeder, turn it Clockwise all the way in until snug, do not overtighten, then back it off 2 full turns and start there, you can then back it out 1/2 turn at a time to adjust the feed accordingly. I think mine is set around 2-1/2 or so.

ALSO, your Timer box, check the PIN settings, you should have approx. 4-5 pins every 10 mins. If you have more, it will cycle the stoker that much more (10-15 secs for every pin) every 10 mins to keep it burning when the thermostat is not calling for heat.

If both of these are not adjusted accordingly, they it will feed much more then it can completely burn. We do get the clumps once in a while too.

The exhaust motor housing should have a cover plate with 4 screws, you should open it and vacuum it out once a month or so and the blades on the direct vent should be checked and cleaned too!

The Combustion blower burn grate section (where the coal actual burns) can get ash under the plate and should be cleaned also, kinda of a pain, but can affect the combustion air feed.
WNY
 
Hot Air Coal Stoker Stove: Keystoker 90K, Leisure Line Hyfire I
Coal Size/Type: Rice
Stove/Furnace Make: Keystoker, LL & CoalTrol
Stove/Furnace Model: 90K, Hyfire I, VF3000 Soon

PostBy: red ash On: Thu Oct 26, 2006 2:24 pm

NEPAForum Admin wrote:You can expect some some clumping and unburnt coal. Also be aware that stoker ash differs from hand-fired ash. I've mentioned this before, I've burned the very same coal that was being used in a Van-Wert stoker in a Franco Belge hand-fired stove and the consistency of the ashes from the Van Wert were as usual slightly chunky. The coal from the hand fired stove was like talcum powder. Barely a speck of anyhting in it.

Having said that the clumps should not be that large and you should be able to break them up easily with your hands. Generally the faster you run it the more likely you are to get these clumps.

There's a old pamphlet here from Van Wert that bescribes how the coal will look when burnt and even metions that it may not all fully burn.



You are right on the money, time on the grate will greatly effect consistency of the ash. As WNY has said keystokers use a timer to add coal to the grate at a set interval this maintains the fire while the thermostat(t.t. for short) is not calling for heat. The timer keeps the ash advancing along the grate at a steady pace and the ash never has the time to turn to a powder like it would on manual shake grates.
red ash
 

PostBy: red ash On: Thu Oct 26, 2006 3:06 pm

byrdy11,wny is correct on the starting point for the coal feed adjustment knob. Could you please explain exactly what you are seeing on the grate when the stoker is calling for heat and what you are seeing when it is not calling for heat. Describe where the ash/fire line is in both situations. Describe the flame color and height at both times. Keystokers should never have raw/unburnt coal falling of the end of the grate! Ash can have various appearances(red,white or pink) as well as slate or Bone material mixed in. These characteristics can fool you into thinking you have unburnt coal in your ash! The coal feed adjustment knob can not reset itself unless it were striped from overtightening! This is what makes me think you may have a combustion problem or a feed imbalance.
red ash
 

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