Coal Stove Into Wood Stove Help

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chefpatrick

New Member
Feb 2, 2021
18
NJ
There is nothing gained by using chimney pipe on the stove if everything behind it is non-combustible right back to the block wall. Regular stove pipe could have been used.

The stove is not ideal. It will never be efficient or clean burning. If the goal is to heat then there are better options.
Thank you for the input... I will start looking for some other stoves, that being said, the set up I'm using now, it's just overkill with the insulated stove pipe? I spent some money on that, just thinking more is better
 

GENECOP

Minister of Fire
Jan 31, 2014
734
Ny
Thank you so much man!

Like someone pointed out, different brands different connections, hard to know for sure, but I used something like that in my connection..
 

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coaly

Fisher Moderator
Staff member
Dec 22, 2007
4,515
NE PA
Thank you for the input... I will start looking for some other stoves, that being said, the set up I'm using now, it's just overkill with the insulated stove pipe? I spent some money on that, just thinking more is better
No, more is not better.
You need to know the basics of what makes a stove work to troubleshoot it.
Hot exhaust gasses lighter than outdoor air rise in the chimney causing a low pressure area in chimney, pipe and stove. This allows atmospheric air pressure to PUSH air into the stove feeding the fire oxygen. The temperature differential between inside and outside of chimney flue causes the pressure differential measured as draft. A fire won't burn in a box without the chimney acting as the engine to make it go. Heat left up the chimney is the fuel the chimney uses to make the stove go.

You should have started with the basics.
1. Chimney support box ; through roof which is a box that is fastened to framing to support the chimney weight. The box is zero clearance mounted to frame members. (the supports outside is to stabilize an extremely tall chimney when needed to get above obstacles within 10 feet of the chimney, it doesn't look like you need that)

Chimney pipe starts inside the box and only needs to be high enough to be 2 feet above the nearest obstruction including roof, measured at 10 feet horizontal from chimney pipe, and at least 3 feet above roof penetration.
(You look way higher than that. A taller chimney creates more draft, but needs more heat to do it. Flue gasses cool as they rise and you need a lot of heat to lift the cold air out of that chimney flue to get it drafting upward. That stove will burn very fast putting enough heat up, but it is also fuel waste)

2. Connector pipe ; black pipe is used inside. (single wall since there is no combustible material within 18 inches of the pipe) If the ceiling height is over 8 feet, double wall connector pipe (black) is better to prevent cooling before it reaches the chimney where heat is required to be kept over 250* f when smoke is present. Your chimney isn't hot enough to make the stove work.

Reasons for single wall;
It radiates heat onto building.
It is easy to put a magnetic thermometer on so you know how to run the stove.
It is easy to put a flue pipe damper in. You will need that with this stove burning wood.
It is easy to put a barometric damper in burning coal. You will need that burning coal.
It's cheap.
Black connector pipe connects to the bottom of chimney support box without issues.

Reasons for double wall black pipe;
Close clearance to combustibles down to 6 inches.
Prevents excessive cooling in high ceiling installations.
(It is not cheap and requires internal probe type thermometer to monitor stack temp)

3. Chimney the correct height outside. How high is it from stove top to chimney outlet? Does it follow the 3-2-10 rule as described above? (3 feet above roof penetration and 2 feet above anything within 10 feet)

The stove itself is not the problem with smoking inside.
A wood stove will smoke inside much worse with a marginal chimney or draft since much less air gets into a wood stove.
You "can" burn wood in any coal stove, just not efficiently. It will burn wood fast and hot, losing a lot up the chimney, hence the need for a flue damper. You can't do that using chimney pipe inside. (unless you have one right where it exits the stove in pipe connector)

Coal gets all air up through coal bed and uses tons of air. Wood doesn't care where air comes from.
Wood should be burned on the bottom of a stove with firebrick bottom. Never directly on stove bottom. Always burn on an inch of ash when cleaning out. This prevents the wood from getting too much oxygen and allows coals to form.
Most coal stoves have a bottom air intake called primary air in ash pan area that allows air up through grate. They will have a way to get air above the fire as well to ignite coal gas. This is called secondary air. Sometimes just a leak around grate, others will have an upper air intake. When they have an upper air inlet, this is only cracked open burning coal for a little air, most coming through the bottom. Burning wood, close bottom intake and only use the secondary upper air.

Since you have no idea of the internal flue temperature, we can't help you as far as the cause of smoking or condensation, but it is surely burning too cool when water vapor condenses and leaks out.
The magic number is 250* all the way to the top. Below this, the water vapor from combustion condenses on flue walls making it wet. Then smoke particles stick forming creosote. ALWAYS stay above 250* to the top when smoke is present. That is the reason for an insulated chimney outside, to stay hotter inside the inner flue keeping it clean, without wasting a lot of heat to do that.

First build fire with paper, cardboard and kindling. It should roar up the stack preheating chimney. At first it may be sluggish since it has to rise up the stack with cold dense air in it. Doors open, twisted paper near the back should heat the chimney enough to start the draft. now you should have atmospheric air pressure rushing into stove preventing it from smoking inside.

Next is moisture content of wood. Is your wood dry (seasoned)for at least a year? Even a proper chimney won't work well with damp or unseasoned wood.
Drying starts when split, not cut down or in round lengths. It will rot on the ground before drying if not split and stored properly.

To take fuel out of the equation, try scrap pieces of kiln dried lumber to see if it ignites and burns properly instead of smoking inside. Kindling needs to be dried as well. Nothing green, or if it sizzles or you see moisture come out of the ends of wood, it's not ready. This will all give you smoking issues since you won't get the chimney hot enough to draft properly with all the moisture carrying the heat out the chimney.
 
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coaly

Fisher Moderator
Staff member
Dec 22, 2007
4,515
NE PA
Once you understand what makes the stove work by the chimney causing the low pressure area in stove and pipe, you can see why you don't need sealer or tape on pipe joints. Air will leak INTO the vent system, not smoke leak out. Leaks cause cooler air to enter pipe and chimney, which is detrimental to draft and keeping it clean. Each joint should be male end down so any condensate stays inside pipe to be consumed in stove. Each single wall pipe joint needs 3 screws.

Your fire is too low in the stove. Bring it up with firebrick or sand in the bottom to the level of intake air openings. Air rushing in to fill the void created by chimney needs to get to the fire to feed it oxygen, not enter above it and rise up the stack. This cools chimney when letting too much air above fire. The fuel on the bottom is probably not getting air. It will only smoulder and smoke.

Is the round opening in stove front an opening into firebox? Was this for the grate shaker that is missing from grate removal and left wide open? The firebox needs to be closed tightly and as air tight as possible when air shutter is closed. Any air leaks into stove will cause the fire to be uncontrollable.
 

chefpatrick

New Member
Feb 2, 2021
18
NJ
No, more is not better.
You need to know the basics of what makes a stove work to troubleshoot it.
Hot exhaust gasses lighter than outdoor air rise in the chimney causing a low pressure area in chimney, pipe and stove. This allows atmospheric air pressure to PUSH air into the stove feeding the fire oxygen. The temperature differential between inside and outside of chimney flue causes the pressure differential measured as draft. A fire won't burn in a box without the chimney acting as the engine to make it go. Heat left up the chimney is the fuel the chimney uses to make the stove go.

You should have started with the basics.
1. Chimney support box ; through roof which is a box that is fastened to framing to support the chimney weight. The box is zero clearance mounted to frame members. (the supports outside is to stabilize an extremely tall chimney when needed to get above obstacles within 10 feet of the chimney, it doesn't look like you need that)

Chimney pipe starts inside the box and only needs to be high enough to be 2 feet above the nearest obstruction including roof, measured at 10 feet horizontal from chimney pipe, and at least 3 feet above roof penetration.
(You look way higher than that. A taller chimney creates more draft, but needs more heat to do it. Flue gasses cool as they rise and you need a lot of heat to lift the cold air out of that chimney flue to get it drafting upward. That stove will burn very fast putting enough heat up, but it is also fuel waste)

2. Connector pipe ; black pipe is used inside. (single wall since there is no combustible material within 18 inches of the pipe) If the ceiling height is over 8 feet, double wall connector pipe (black) is better to prevent cooling before it reaches the chimney where heat is required to be kept over 250* f when smoke is present. Your chimney isn't hot enough to make the stove work.

Reasons for single wall;
It radiates heat onto building.
It is easy to put a magnetic thermometer on so you know how to run the stove.
It is easy to put a flue pipe damper in. You will need that with this stove burning wood.
It is easy to put a barometric damper in burning coal. You will need that burning coal.
It's cheap.
Black connector pipe connects to the bottom of chimney support box without issues.

Reasons for double wall black pipe;
Close clearance to combustibles down to 6 inches.
Prevents excessive cooling in high ceiling installations.
(It is not cheap and requires internal probe type thermometer to monitor stack temp)

3. Chimney the correct height outside. How high is it from stove top to chimney outlet? Does it follow the 3-2-10 rule as described above? (3 feet above roof penetration and 2 feet above anything within 10 feet)

The stove itself is not the problem with smoking inside.
A wood stove will smoke inside much worse with a marginal chimney or draft since much less air gets into a wood stove.
You "can" burn wood in any coal stove, just not efficiently. It will burn wood fast and hot, losing a lot up the chimney, hence the need for a flue damper. You can't do that using chimney pipe inside. (unless you have one right where it exits the stove in pipe connector)

Coal gets all air up through coal bed and uses tons of air. Wood doesn't care where air comes from.
Wood should be burned on the bottom of a stove with firebrick bottom. Never directly on stove bottom. Always burn on an inch of ash when cleaning out. This prevents the wood from getting too much oxygen and allows coals to form.
Most coal stoves have a bottom air intake called primary air in ash pan area that allows air up through grate. They will have a way to get air above the fire as well to ignite coal gas. This is called secondary air. Sometimes just a leak around grate, others will have an upper air intake. When they have an upper air inlet, this is only cracked open burning coal for a little air, most coming through the bottom. Burning wood, close bottom intake and only use the secondary upper air.

Since you have no idea of the internal flue temperature, we can't help you as far as the cause of smoking or condensation, but it is surely burning too cool when water vapor condenses and leaks out.
The magic number is 250* all the way to the top. Below this, the water vapor from combustion condenses on flue walls making it wet. Then smoke particles stick forming creosote. ALWAYS stay above 250* to the top when smoke is present. That is the reason for an insulated chimney outside, to stay hotter inside the inner flue keeping it clean, without wasting a lot of heat to do that.

First build fire with paper, cardboard and kindling. It should roar up the stack preheating chimney. At first it may be sluggish since it has to rise up the stack with cold dense air in it. Doors open, twisted paper near the back should heat the chimney enough to start the draft. now you should have atmospheric air pressure rushing into stove preventing it from smoking inside.

Next is moisture content of wood. Is your wood dry (seasoned)for at least a year? Even a proper chimney won't work well with damp or unseasoned wood.
Drying starts when split, not cut down or in round lengths. It will rot on the ground before drying if not split and stored properly.

To take fuel out of the equation, try scrap pieces of kiln dried lumber to see if it ignites and burns properly instead of smoking inside. Kindling needs to be dried as well. Nothing green, or if it sizzles or you see moisture come out of the ends of wood, it's not ready. This will all give you smoking issues since you won't get the chimney hot enough to draft properly with all the moisture carrying the heat out the chimney.
Wow man, that was incredible. Thank you so much. I did follow the proper rule for the chimney height, so at least I have that going for me. Next plan would be to clean out any spray foam, ensure my two inch clearence is good and look for the proper parts that you described... I will keep posting pics with progress... I am happy I don't have to bail on that stove, and if I get back half of what I paid for those insulated stove pipes I'll be in good shape
 

chefpatrick

New Member
Feb 2, 2021
18
NJ
Wow man, that was incredible. Thank you so much. I did follow the proper rule for the chimney height, so at least I have that going for me. Next plan would be to clean out any spray foam, ensure my two inch clearence is good and look for the proper parts that you described... I will keep posting pics with progress... I am happy I don't have to bail on that stove, and if I get back half of what I paid for those insulated stove pipes I'll be in good shape
Also if you of anywhere I can get the right chimney support box? Everything online looks like it is made to go through a flat roof?
 

bholler

Chimney sweep
Staff member
Jan 14, 2014
28,156
central pa
Found it... Will post all things happening from now on...you guys are awesome
It should all be the same brand as the chimney you are using
 

coaly

Fisher Moderator
Staff member
Dec 22, 2007
4,515
NE PA
It would be called a cathedral support box. Same thing only deeper since the roof is much thicker than mounting the box between ceiling joists. The bottom edge of box has to be 2 inches below the finished ceiling surface. (or 2" below the lowest edge of roof rafter) Normally a support box is for a flat finished ceiling and the chimney you used inside is used above the support box in the attic or going through a second story above the support box. Then stainless inside and out is used outside for weather resistance. The box needs to be the same brand as chimney. All chimney parts are tested as a unit and UL approved to be installed as tested. You can't mix different brands of chimney parts.
 
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coaly

Fisher Moderator
Staff member
Dec 22, 2007
4,515
NE PA
Not sure what 2 inch clearance you're referring to. When you cut the hole in roof for the support box, you frame right up to the box. I box framing in to fit, and level box from the bottom. Mark corners and drill pilot holes plumb through roof, marking the cut out for box. Connect the dots on the roof, and cut roof deck. Insert box, level and screw or nail in place. You will have the box sticking up on the low side of roof. Cut flush with roof so flashing sets flat on roof. Where the chimney section is mounted in the box, there is the same end sticking up as a chimney section, so the first pipe section locks in place in the box. Then set flashing over the box, using the pipe to position it. Nail down depending on roofing material and install storm collar. Caulk or silicone the storm collar to prevent water running down pipe into support box. This gives the correct clearance around pipe to roof material. If you have shingles, the flashing slides up under the shingles from the center point of flashing, and goes over the shingles on the lower half side. Just like a big shingle on the roof.