HF-70 Keystoker

I have been reading some post over the last week and you guys are getting me worried about my stove.

The price was right it was a gift keystoker hf-70 in good condition and working on installing it soon.
I live in upstate new york so we have some cold around here I read some where that you can make the fire box smaller with brick or steel and reduce the amount of coal you are burning allowing burning when its not frezzing out.
Does anybody have any experience with this type of stove any help would be great.

I have burned wood for ever so I have some experience with the work involved.

thanks

Tim

Hi Tim, welcome to the forum. Your Keystoker stove is a fine stove. Why are you concerned about reducing the firebox size?? With most instalations you can control the heat output enough to use the stove as is.

Tell us about the house you are installing it in. How many square feet? Quality of the windows, and how much insulation? what type of heat does your house currently have? Are you planning on using the Keystoker stove to augment your current heat? Or will the stove be the sole source of heat?

What type of chimney do you have? A Stainless Steel or a Masonry Chimney?? What inside size and what height?

And... how long between loading and shaking will the stove need to burn?

As you can see from the list above there are a lot of factors about burning coal, and the expectations we can have for our burning experience.

Give us some more information and we'll be able to help.
If you are currently burning wood, you will like the even heat and longer burning time from coal.

Greg L

Check your PM's

Thanks in advance for your help

The box is 10" tall 12" wide and about 14" Long the reason I ask about the reducer is because it might be 60 during the day and then get down to about 40 at night and if I could start just a small fire I could keep the chill out and it would be comfortable in the house in the morning when we get up.
I have a tall 8 inch stainless chimney running up the middle of the house with about 4 foot above the peak.
The stove has a top flue which is 6 " it will have a regular damper and A barometric damper(which I will also have questions about soon )
The house has good windows ans decent insulation I believe I never had to much trouble keeping us warm with wood but it was not very constant

Well, with a tall chimney you should have good draft, with the barometric damper, it should be good and consistant draft. With these, you should be able to close down the air to the coal quite a bit and get it to just idle along.

Most of the guys who use a firebox reducer have a huge firebox, like Cap, who has a Harman SF250, which holds about 120# of coal!!.. His firebox is roughly [I'm not sure about these diementions] 15" wide, 26" deep [front to back], and can be filled about 10" deep. A LOT of coal. He builds a false back wall at about the halfway point, making it about 15" front to back.

Not all fireboxes lend themselves to this process. Take a look in your firebox, move the grate shaking handle, is there a ledge on the sides of the firebox between the grates and the firebrick that you could rest a flat steel plate, covering the grate from side to side but NOT restricting the shaking action of the grates?? Cap's Harman has a raised steel ledge that works perfect, he cut a piece of 1/2" steel to go from firebrick to firebrick, resting on the steel ledge, the grates can move below the plate unhindered. He then stacks new firebrick on the front of the steel plate, makeing a new rear wall to contain the coal. I think he backsup the firebrick with more bricks back to the original back wall. Firebrick are cheap, about $1.50 each. Last forever as long as you don't drop them!

A smallish fire for the cool autumn nights is a good idea, You may do fine without a firebox reducer, or may decide your want one.

I hope my text description makes sense, The bottom line is you have to block off all air coming up through the grates except for under the burning coal. a coal fire will go out without air being drawn through from underneath. so as long as you can block off the rear portion of the grates and make some sort of firebrick false wall, then you should be OK

Take care, Greg L

I can make what ever I need to block off the extra space my ledge is flush with the top of the shaker grate but there is some room to lay steel between the fire brick and the ledge which would block the air.

I guess from reading on here that coal likes to be deep to burn is it possible just to lay down say 2 " of coal the entire length of the grate and have it burn?? Does it need to be full to work right
I'm thinking it will be way to hot if I have to fill the box.

The shaker grates open up like 2 inches when stroking the handle from front to back I thought maybe just wiggling the handle enough to drop out the fine ash would be enough. If wiggling it will work the steel plate just moves up and down and cant move out of position.

How hard do you have so shake to get the job done?

Do you think I can close the ash door draft and the spring controlled draft in the back and have it still burn or will it go out. If you know what I mean

Thanks

Tim

Hi Tim, the amount of heat produced is determined by the area of the coal, the length of the burn is determined by how deep the pile of coal you have. Actually a 10" deep bed of coals will idle down and burn slow much better than a shallow bed of coal.

A thin bed of coal usually goes out. The coal pieces won't burn independantly like a piece of wood. Coal is a 'comunity fuel' [can't think of a better term] each piece of coal gets warmed by the adjacent piece, the air flowing up between the pieces in the coal bed is what keeps the fire going.

Coal will quickly go out if taken out of the coal bed. I've taken a shovel full of coal from one fire and carried it over to start another fire, and the red-hot glowing coals always go out. The coal bed works when it is deep and not stired up too much other than shaking the ashes down.

Your question about the amount of shaking needed depends on your coal. Some coal has a hard crusty ash that needs to be shaken pretty hard to get it down through the grates and into the ash pan. Some other coal turns into a light powdery ash and only a minor shake of the grates is needed for it to drop through the grates. The whole reason to shake is to open up the air passageways between the coal pieces to restore air flow.

I would try your stove as is, just build a nice wood fire, let it burn down to a good bed of hot wood coals, then shovel on about 2-3" of coal, let it catch, you will see little blue-white flames come up through the black coal. Let this get burning well, for 20 minutes maybe then add enough coal to fill the firebox to the top of the firebrick. Let this get burning well for 20 minutes or so then turn down the air to the fire.

Each stove, chimney and coal combination is different. So I can't advise how much to turn the air down. If you can guage it from how a wood fire responds this will give you a starting point. If you have a spinner knob on the ash pan door, somewhere around 1/8 to 1/2 of a turn. Every stove and air damper is different.

Hopefully someone with the same or similar stove will post some info for you.

Putting a steel plate on the grate, causing the grates to have to move the plate to shake will not work. The motion will knock over the firebrick wall you have built on the plate. If you try to block off part of the firebox, you need to not restrict the grate motion. But I would try your stove without the reducer, you probably will be very pleased with it as is.

Greg L

I will try it without a reducer but I was thinking If I made a L shaped piece half of the L would be on the shaker grate and the other would have the coal up agianst it so really the air would be coming through the coal and the metal piece would just rock around when shaken.

I guess asking how long it might burn if full would be a tough guess as well

I've made a metal back wall, and it only lasted a week or two, the coal up against the steel turned the steel into slag, I could break pieces off with my fingers!!

The firebrick are necessary. Can you put a short bend or weld on a spacer on the edge of the plate so it rests on the ledge and or the pivot points of the grate?? The grates will be very difficult to shake with weight on them.

Greg .

Yeah I was thinking about doing something with spacers also 1/4 stainless shouldn't burn up should it.

S/S will take longer but it will still give up quickly. Any steel exposed to the burning coal will dissapear, that is why they use firebrick between the coal fire and the steel. The only way steel can take that kind of heat is if there is water on the other side of the steel from the fire.

Point taken, brick if I need to make something to reduce firebox size.
Now that I thinkI have that figured out with your help of course,On my chimney above my wood stove(6")I have what I think is called a slip flange or something like that. it's a piece of black iron pipe slighlty smaller than the 6" stove pipe
It allows me to take the pipe apart for cleaning the chimney and makes it easy to get everything hooked up.
I can use that on the coal stove as well correct

anybody have any info on the slip deal that I tried to explain above

Also

How about info on stting a barometric damper

Thanks

Tim

Anybody??

The slip pipe should work fine if it worked for wood.

Setting the baro damper 'correctly' requires a Manometer to check the draft. Usually there are some settings on the damper's adjustment.

Do you have instructions that came with the baro?

Greg L

mina678 wrote:How about info on stting a barometric damper

http://www.fieldcontrols.com/pdfs/draftcontroltech.pdf