# Antique Parlor Stove - Mystery Draft Control...



## Peter B. (Dec 1, 2008)

I'm still burning in an antique Round Oak parlor stove, which has served me well, off and on, for over thirty years.

Something I've always been in question about is the utility of a sliding draft control at the top rear of the stove... just below where the flue pipe attaches.

It opens or closes three 1" diameter holes in what is (effectively) the main rising exhaust flange before the smoke enters the flue.

The only function I can think of it might have is to 'break' an overstrong draft under certain wind conditions.

Never having understood its (intended) utility, I've never used it, but kept it closed at all times.

Any ideas?

Thanks.

Peter B.

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## mmichaud (Dec 2, 2008)

I have a round oak E -18 and have the same damper design. I think it was to help in a overdraft situation. Never really gave it much thought.

Mike


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## Backwoods Savage (Dec 2, 2008)

We always opened those 3 holes once the fire got going good but closed them when adding wood.


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## Peter B. (Dec 3, 2008)

Thanks for your replies...

I think we've all got it right, the control was (likely) intended to cut the draft some.  It just doesn't seem as though it could really help that much.  I've removed mine and blanked off the holes.

Peter B.

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## mliiiwit (Jan 4, 2012)

Peter B. said:
			
		

> I'm still burning in an antique Round Oak parlor stove, which has served me well, off and on, for over thirty years.
> 
> Something I've always been in question about is the utility of a sliding draft control at the top rear of the stove... just below where the flue pipe attaches.
> 
> ...




Peter,

The draft holes at the top rear of the Round Oak stove are for secondary combustion air.  For a visual of this (if you have an opportunity), burn an un-modified Round Oak outside at night with 6' of pipe on it.  When you get a good fire going, you will get flames out of the top of the 6' of pipe with the secondary combustion draft open.  As indicated in another post as being per original instructions, this secondary combustion will reduce the amount of creosote build up by INCREASING the flue temperature by burning the unburnt gases (i.e. smoke) from the firebox, thereby eliminating from the flue gas the components necessary for creosote formation.  I'm guessing this practice also extracted a lot more heat into the typical home the stove was designed for - one with 9 or 10 foot ceilings, i.e. more stove pipe in the living area.

Reading your other posts on extracting heat, stick with the ideas of extracting heat from the flue gas.  As long as you achieve secondary combustion - which you may be doing inside your Round Oak with the catalytic, cooling the flue gas after secondary combustion will not cause any increase in creosote buildup.  It may affect draft depending on your setup and how much you reduce the flue gas temp.  Cool the flue gas enough and you'll also have water condensing in the flue.

RE copper coils around the fire pot:  The primary combustion area should be kept as hot as possible to effect complete, efficient and clean burn of the fuel and provide sufficient heat for secondary combustion.  INSULATING the primary combustion area would be more beneficial than cooling it as long as you have a system to extract the heat from the flue gas.  Cooling the primary combustion area will tend to suppress any secondary combustion, resulting in increased creosote deposits.

For more relevant information, read up on masonry heaters.  In a masonry heater, the fire is ALWAYS burnt full hot (only 1 or 2 relatively small fires per day) and the heat is extracted from the flue gases by a LONG serpentine (either vertical or horizontal) masonry flue.  When used correctly, i.e. a full firebox completely burnt full hot, there will be no problem with creosote buildup even though the gases are cooled well below any temp recommended for a standard straight up flue.

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## Peter B. (Jan 4, 2012)

roundoak:

Thanks for your take on the draft control... it's not one that had occurred to me... or - to be honest - one that would.

But I realize these stoves were often burned full out, and that as you say, flames probably shot well into the stovepipe in 'normal' use.  The philosophy and methodology of extracting heat from wood has changed a bit through the years, eh?

I think most users of modern stoves have come to think of secondary air as *preheated* air, but I think 'technically' secondary is any *overfire* air.  I could be wrong.

I refreshed the D-16 this year with a new catalyst and new (rudimentary) preheated secondary air supply to the firebox, piped (perhaps ironically) from one of the holes of the rear draft my original post was about.

Unfortunately, my wood is not well seasoned this year and I'm struggling... while (also) learning slightly different burn characteristics of the stove with the refreshed modifications.

I'm beginning to get better results from changed tending practices.  Yesterday saw a solid four hour burn from hot coals to hot coals, with good heat output on a partial load.  Even that much has been difficult to manage with this wood as yet.  I'm pleased to be making a little headway.

Incidentally, I abandoned the water heating coils after only a couple of seasons, so there's little cooling of the firebox in play.  The inside of the firebox is lined (part way round) with firebrick splits in an effort to elevate firebox temperature somewhat.  

I'm more or less familiar with the fundamentals of wood combustion, and it has been interesting to note that as measured by a probe thermometer inserted through a drilled hole in the 'dome' of the stove, with a good hot burn in progress, I can see temperatures in excess of 1200-1300 degrees, which I believe is sufficient for fairly complete combustion.  Similar temps can be achieved with or without the catalyst.

It makes me wonder what temps exist in the vicinity of the coal bed.

Are you still burning in a Round Oak?

Again, thanks for your post.

Peter B.

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## mliiiwit (Jan 5, 2012)

Peter,

I grew up on wood heat and cut, split, loaded and stacked about half of what we burned.  Many hours spend at the side of a buzz saw.  However, I have not heated with wood in my own home as yet - some day.  I just got my Round Oak Thanksgiving '11 from my parents who had moved it out of the house they bought in 1963 and stored it in a shed, where it sat until I acquired it.  It had been replaced with a gas stove before they bought the house and was sitting in the corner of the room.  Their house was built in 1887 or 89 so the RO may have been one of the original heat sources (there were 2 chimneys in the house but there was only the one gas stove in use when they bought the house).  No idea what the 2nd original heat source might have been.  Anyway, after at least 48 + years of sitting cold, I've fired the RO a few times out back of the shack, just for the enjoyment.  I'd never been around a burning RO but had liked the looks of the stove since I was a kid.  And wow, will it put out the heat.  Even out on the patio in the 30's you can easily tell you'd only need small fires in it most nights here in SC Kansas.  I have a bunch of pecan stacked up from a couple trees I took down a couple years ago so have some good, well seasoned wood to burn in it.  I burnt it with the drafts wide open and modulated the heat output by the loading.  Once the stove is warmed up, there was no visible smoke from the 6' stack and it seemed to achieve secondary burn in the stove with a small load and in the stack with a larger load.  My RO is complete except for one leg badge and the finial.  It is just like this one except mine has foot rests on both sides:

hearth.com/gall/v/AntiqueandOlderStoves/round-oak-stove-002.jpg.html

I've been studying stoves, fireplaces and heaters for a few years now and have learned a lot in that time.  I'm experimenting now (out back o' the shack) with extracting heat from the flue gas using a junk cast boxwood stove I got for free, some stove pipe and a 55 gallon drum.  I've burnt my setup once and have been able to reverse the draft downward into the drum after a 6' rise out of the stove.  I put a cleanout T at the top of the 6' of pipe, installed 2 elbows out of the cleanout and pipe straight down into the top of the drum, which has a second 6" + hole in the bottom.  After getting the stove hot, I put the top lid from the RO on the top of the clean out T to force the gas downward into the drum.  Smoke leaked from the pipe joints until the drum warmed up then the leaking stopped.  Temperature of the gas exiting the bottom of the barrel was cool enough to hold your hand in indefinitely.  The top of the drum was soon too warm to hold your hand on and eventually the bottom of the drum got nearly as warm.  However, even at that point the exit gas was not hot enough to burn you.  And there was no acrid smoke smell to the exhaust gas at all.  There was however, some steam and water (expected).  My next step is to add a vertical stack originating from the bottom of the drum to see if that will shorten the time of leakage from the pipe joints when the upward gas flow is directed downward.  So I'll then have 3 vertical stacks, 2 upward and one downward with a large heat exchanger in it(the drum).  I want to extract the heat during downward flow of the flue gas so as to achieve best heat exchange efficiency with natural convective flow of the heated air.  Not to say I wouldn't use a fan, but I don't want one to be necessary.

Eventually, I also plan to add a combustion air heat exchanger near the outlet of the flue gas path.  Cold outside air will be drawn in and pre-heated by the then-cool flue gas and then routed to the stove for combustion.  This last step will hopefully bring the ultimate flue gas exhaust temp down to within 30-50 degrees of outside ambient and eliminate consumption of warm indoor air for combustion.  I also hope that having both the combustion air source and the flue exhaust in near proximity will help to prevent any negative effect to draft from pressure gradients as wind blows around the house or trees, exterior doors or windows are opened/closed, etc.

Maybe a lot to digest, but I'd appreciate any and all feedback.


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## Peter B. (Jan 5, 2012)

roundoak16 said:
			
		

> I'd appreciate any and all feedback.



roundoak:

In fact, I don't really feel qualified to offer much but pretty raw opinion.

The experimental setup you're putting together sounds interesting... sort of an external baseburner design?

To be honest, were it me, I don't think I'd want an exhaust flow like that indoors... too much chance of cooling the draft to the point that smoke and carbon monoxide leakage would result.

I consider that I was pushing things when I modified my own stove internally.  Without going into a lot of other detail, the exhaust path out of the firebox passes through a rectangular steel duct that opens (only) about 6-8" above the firebox floor... and communicates with a chamber in the top of (but isolated from) the firebox proper.  The smoke then passes through a right angle and...

In any event, with no effective bypass, smoke enters the room pretty reliably when the loading door is open, making tending the stove (when the fire is reluctant) a nuisance.  And I have been concerned at times that _somehow_ the flue might become partially blocked in the night and...

I live alone so there's no one else at risk.

I continue to wake reliably in the morning after twenty years on the modifications, but I would alter my design if I were to do it over again.

--

I corresponded with another member here at Hearth.com a couple of years ago who had (figuratively) built his house around an antique Geneva Oak cylinder stove.  I don't now remember all the details of his hearth and chimney, but they were intended to withstand running the Geneva full out... and for safety's sake I think a setup like his is the only way to go if you hope to burn in that fashion.

--

The stove in the photo you linked to looks to be a D-16 - same as mine.  Mine was painted all black when I bought it in 1975, and I've never bothered to have anything re-nickled.  I'm missing the finial too.  I also rotated the 'dome' of the stove 90 degrees to make it front load / rear exhaust, rather than the original 'side saddle' arrangement.

I've had a lot of fun with the stove over the years, and I don't think I could live without a 'powerful' radiant heater in my home.  But if I had my druthers, I confess I'd rather be able to watch the fire... and the 'Northern Lights' secondary burns... through clear glass.

Peter B.

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## webbie (Jan 5, 2012)

I'm in agreement that the holes provide draft reduction - and sure, draft reduction and overfire air can help a little secondary burn with coal (the little blue flames).

It sounds like the equiv of a barometric damper, which does the same basic thing (lets air into the chimney to spoil the draft), but adjusts itself due to the weighting of a swing door.


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