Ember Hearth stove

[BrotherBart]

@Ember Hearth

I have an old Ember Hearth wood burning stove that seems to be in fairly good condition for its apparent age. My research shows me that the Ember Hearth company went out of business in the 1980 timeframe after many years of producing wood burning stoves. I have no history on this particular stove, but it is free-standing (not an insert) with an 8-inch exhaust pipe, a flat top for cooking, twin doors, and a rear squirrel cage blower. There are front vents that appear to be air input ports to the fire box (which is lined with fire brick on the bottom). It has both steel and cast iron parts. The twin doors on the front allow logs to be placed inside sideways into the fire box and seems to be easy to clean. There is a flat horizontal steel plate that is loosely connected between the legs on the bottom of the stove. I assume that this is a heat shield for the floor. I am including a picture of the front of the stove.

BACKGROUND: I designed my house out of steel (no wood construction-- similar to hurricane-tolerant homes in Florida, although the home in is the mountains of North Georgia. It has fiber-concrete Nichiha siding, fireproof sub flooring, 5 / 8 fire rock everywhere, and the basement is poured concrete. I have geothermal heating and solar power augmenting the grid, but there are circumstances where these could all fail, so I plan to put this Ember Hearth wood burning stove in my basement next to my welding bench as an extra work surface, but in an emergency situation, I'd like to be able to use it for heat and maybe boiling water. It is hard to justify a nice new efficient wood-burning stove when it may never be used as a stove/heater, only coming into play during an extended power outage due to a grid catastrophe.

QUESTIONS:
1. Does anyone out there have specs/plans/user's manuals for this Ember Hearth stove (or one like it)?

2. I live on 50 acres of hardwood woodland (oak/hickory) so I have plenty of opportunity to gather fuel, but I also don't want to create a fire hazard. The design I am considering is to have the stove near my welding bench which is in a corner surrounded on two sides and the floor by poured concrete. I would like to run the exit flu through a hole in the concrete wall that is about 4 feet above the stove and below the steel ceiling girders (a steel heat isolation plate would be placed above the pipe and below the girders). Next to that would be another hole that would supply outside air to the stove. The plan is to cut into the firebox plenum so outside air could feed the fire through a control valve. At the same time, I would seal off the room-air input ports that currently feed the fire box. The stove pipe flu would go up 4 feet and turn horizontal to go through the concrete wall. An outside section of pipe would continue horizontally to a point about 12 feet from the house at which point it would turn vertical into a stack of about 10 feet. The stack would have a screen cap on it. The outside piping would be removable for storage inside, and both the flu and outside air ports coming thought the concrete wall would be capped off when not in use. During time of extended emergency, the caps would be removed, a screen cap placed over the air intake, and the flu chimney assembled and supported with guy wires for extended use. Data points: the basement is unfinished concrete containing workshops, laboratory space, storage, and a tornado room (all about 3400 sqft). The upstairs living area is 3400 sqft with 10 inches of fire-proof insulation in the walls and ceiling (yes, the insulation in the walls is 10" thick). Here's the question (finally!!): does anyone have constructive engineering or safety comments about this approach regarding the stove?

3. I see no reason to use double-wall flu pipe... any reason I should? (it never passes through anything flammable). I plan NOT to use flu pipe "elbows" but rather "Ts" with a cap over the unused end of the T. That will allow me to easily clean out straight sections of the flu simply by removing the end caps for brush access. This will make very frequent cleaning more likely (once a month rather than twice per season).

4. At what temperature should I run the flu pipe to minimize creosote build up?

5. Does anyone know of a baffle system or method to assure that sparks/embers do not make it out of the vertical flu stack?

6. Any other suggestions?

Thanks in advance to everyone making it through this long post and responding.

 

[Hogwildz]

Boat anchor

 

[Ember Hearth]

Don't look a free boat anchor in the mouth!
Fortunately, tonight I discovered a painted-over plate on the back of the stove that, after removing the paint, gives some operational details and date of testing/manufacture. See attached photo:

 

[MAD MARK]

Boat anchor

Yep

 

[webby3650]

I guess I don’t get it. Is this a bump? It’s a boat anchor no doubt...

 

[Hogwildz]

I tink it's someone's alter ego.

 

[Ember Hearth]

Being new to the forum, I mistakenly posted my questions as a "private note", so BrotherBart was kind enough to repost it for me here. Thanks BrotherBart for your help!

 

[Jan Pijpelink]

Initially I was thinking @BrotherBart was pranking us.

 

[BrotherBart]

We don't have a tool to move private convos to forum posts and I didn't want him to have to retype that detailed post.

 

[Jan Pijpelink]

We don't have a tool to move private convos to forum posts and I didn't want him to have to retype that detailed post.

Select all, copy, paste. 3 mouse clicks, 6 seconds.

 

[BrotherBart]

Select all, copy, paste. 3 mouse clicks, 6 seconds.

Kinda sounds like how I got it over here, doesn't it?

 

[BrotherBart]

Now returning to our regularly scheduled program.

Helping him with his questions.

 

[webby3650]

So, are you planning to run the pipe 12’ horizontal before turning vertical? Why not just install a proper chimney? Not only would it be safe, but you’d be able to fire it up any time you wish, not just in an emergency situation.

These stoves are typically creosote factories, pair that with single wall stovepipe out in the cold and you can expect big problems. Not to mention insurance will never go for it, even if the home is “fireproof”.

 

[Ember Hearth]

Thank you for replying webby3650. There is no viable path straight up from the intended location to access the roof, so from the basement I really have to take the stack outside through the concrete wall. I was wondering about the efficacy of taking the pipe horizontal, and how long of a horizontal run would be acceptable (I could have a slight rise of the horizontal section, but it would be maybe only 1 or 2 feet in twelve). The horizontal section is just to get the vertical stack away from the side of the house. I've seen people who had long 30° - 45° sections on wood burning stoves. Based on that, I was thinking that the vertical stack sections on either end of a horizontal run would provide enough momentum in the gas flow to suck it through the horizontal section separating the 4-foot vertical stack right over the stove and the 10-foot outdoor stack.

Is the use of a double-wall pipe a better idea to keep the temperature in the stack higher so that creosote does not form as readily? I was thinking that double-wall pipe was just for insulation as you punched through flammable things like wooden roofs. This is why I asked question "4" in my initial posting.

This stove would essentially be a "welding bench" until a critical infrastructure disaster (hopefully NEVER) happened in which electrical power was unavailable for an extended period (months/years). I won't debate the fragility of our power grid here, but it is seriously vulnerable from a number of both man-made and natural causes. Be that as it may, this stove would only ever be used in an emergency at a time when no body is going to be worrying about insurance and inspectors. If I were going to heat with wood on a regular basis, I'd buy a new stove and put it in a more useful location, but with my super efficient geothermal HVAC system, its hard to justify installing an every-day wood stove-- its just that under conditions when the geothermal system won't work any longer, the wood stove seems like a great alternative.

My main concern is how to make this inefficient stove functional only in an extended emergency, and do it safely without burning up the stove, burning up the surrounding woods, or asphyxiating me and my family in the process.

 

[begreen]

A long horizontal run is almost a guarantee for issues and creosote buildup. Why can't the chimney pipe be properly attached to the house?

 

[Ember Hearth]

The stove pipe begins about 3 feet from the concrete wall in the basement, so it would go up and turn 90 degrees to go out through the 10-inch concrete wall (lets call that 12" to simplify the math), so we're at 3 feet behind the flue origin at the top of the stove. The the overhang on the eve of the roof is about 18" and its structural (can't go through that, and its steel anyway). So we're at 4 ½ feet from the stove's rear. Clearing the eve by ½ foot would put us at 5 feet horizontal distance from the stove. The pipe could turn 90° upward at this point and go up. However, there is a concrete retaining wall about 7 feet away that would provide a good base support for the vertical pipe, so running another 7 foot length of pipe horizontally would make 12 feet to the up-turn where the pipe could then rise however high you wanted it to go (I arbitrarily chose 10 feet to get the top up away from the ground for a total height from the stove of 14 feet.

That was the rationale, but the horizontal distance could vary around 6 feet one way or the other and the outdoor stack hight could vary as much as you want it, considering stability (being steel guy-wired to hold it up securely in the wind without having a chimney structure to do that). I can see that horizontal runs are a catch-basin for creosote, especially if outside in the cold. If the clean-out is easy (as described with my removable "T-end" idea (see Item 3 in the original post)), I wonder how fast creosote build-up occurs? A "clean-after-every-5-days-of-use" regimen might mitigate the likelihood of a creosote fire.

Any thoughts on that? With an outside air source, as described, the main safety issue seems (to me) to be the prevention of creosote buildup and the prevention of sparks leaving the stack. The other big issue is assuring that the flue actually draws well and can be shut off with a valve (same with the outside air source). The size/weight/inefficiency of this stove seem to be minor issues when there is no other heat source during an extended winter emergency where fuel (wood) is abundant.

 

[webby3650]

This stove with that chimney set up is very likely to build up a lot glazed creosote. How do you plan to remove this in a steel pipe? We use a device with spinning chains to literally chip it out of a clay liner, unless it a steel well casing, it’ll blow it apart...

 

[begreen]

I think I'd notch the eave and put the stove right next to the concrete wall to shorten the horiz run as much as possible.

 

[Ember Hearth]

I was planning to use a long pole and a wire brush sized for the pipe like I've seen chimney sweeps doing on You Tube. Is that too weak to do the job? Being conscientious and cleaning more frequently, I was hopeful to prevent appreciable creosote build-up (cleaning as mentioned above, on a weekly basis). Is that unrealistic-- does the creosote build up to combustably dangerous levels in that short a time? (I have not experience with this). I can certainly see that letting it go for an entire season and only cleaning once at the end of the season could be problematic. Do those creosote-busting logs work, or is that a gimmick? As to the pipe, I was planning to use regular thin wall steel stove pipe, but, I do have access to thick wall (¼ and ⅜ inch) steel pipe which would be particularly useful for the near horizontal run. That stuff is heavy, but would be supported at both ends.

 

[Ember Hearth]

If this were new construction, notching the eve would be a consideration, but at this point, the integrity of the steel roof section would be compromised and would be a significant undertaking because the edge of the eve is a structural member just like every other roof section (not like wood construction). Also, since this is an emergency heat source in time of need only, permanent installation of a stack which might go unused (hopefully) for decades necessitates a different cost mindset than were I installing a regularly used wood burner.

 

[begreen]

I was planning to use a long pole and a wire brush sized for the pipe like I've seen chimney sweeps doing on You Tube. Is that too weak to do the job? Being conscientious and cleaning more frequently, I was hopeful to prevent appreciable creosote build-up (cleaning as mentioned above, on a weekly basis). Is that unrealistic-- does the creosote build up to combustably dangerous levels in that short a time? (I have not experience with this). I can certainly see that letting it go for an entire season and only cleaning once at the end of the season could be problematic. Do those creosote-busting logs work, or is that a gimmick? As to the pipe, I was planning to use regular thin wall steel stove pipe, but, I do have access to thick wall (¼ and ⅜ inch) steel pipe which would be particularly useful for the near horizontal run. That stuff is heavy, but would be supported at both ends.

One the flue passes through the wall from the room only Class A chimney pipe can be used. Everything proposed so far is as if one was designing a system to make and collect creosote.

 

[Ember Hearth]

OK, thanks for the guidance. I've clearly got to do some reading. "Class A chimney pipe"-- need to look into that. Creosote formation appears to be the biggest issue with this project, so I need to read up on its formation. So far I've learned that certain wood types and "wet" woods promote creosote formation as do cooler temperature surfaces which allow it to form/precipitate out. Getting a better handle on "creosote" should tell me how to design an effective stack relative to the location of the stove.

 

[Ember Hearth]

OK, after doing some reading, this is the design for a removable stack (used only in times of extended power outage) that can be easily cleaned on the ground and stored when not in use. The cover/cap closes off the hole thought the concrete wall leading to the stove, but is otherwise placed on the deployable stack as shown. This allows access for easy clean-out of the (now shorter) horizontal pipe run on a frequent basis. Comments?

 

[begreen]

The cross fitting at the base of the chimney does not exist. The pipe should be supported off the building and a tee at the base of the chimney with a cleanout cap on the bottom. There is no need to remove the chimney. Consider the installation permanent. The chimney must extend past the roof enough to honor the 10-3-2 rule. The chimney must end at least 3' above the roof and at least 2' above any portion of the roof within 10'.

 

[Ember Hearth]

10-3-2 rule... got it! As mentioned in my original post, I want to have an outside air source for the stove rather than reheating heated indoor air and blow it out the stack. The old Ember Hearth stove has two room air input ports the lead to the firebox. They are located on either side of the front doors (down toward the bottom). They lead to a plenum on either side of the firebox that runs the depth of the stove. The air input ports have screw-on covers that gradually expose more of the outside plenum opening as they are screwed out. Screwing them in cuts off the external air source altogether. Each plenum has at most 3 square inches of air flow to feed the fire near its base (6 square inches total). The output from the firebox is right at 50 square inches, so it seems that the air input to the firebox must draw at a significant speed/suction.

I’m kind of surprised that the external air input ports are so small. Is this typical for wood-burning stoves?