# Oil Furnace and Wood Stove on Same Flue



## jpmako (Dec 18, 2013)

We are moving to our house in Maine after the new year. The current set-up is, in the basement an oil heater and our Cawley 600 wood stove share the same flue. Upstairs we have an older insert with a blower. Although the set-up in the basement is "Grandfathered", I know that this is not an ideal. Since we are moving to the house during the winter I have some questions regarding safe burning practices. Being that the house is vacant, we turned the heat to 55 degrees to save on heating oil. When we arrive I will obviously turn the heat up to make the house comfortable. Since we have a stove in the basement and an insert upstairs, I would like to primarily heat with wood.

My questions are:

1. Can I use the wood stove while the heat is turned on?
2. Should I worry about using the stove and oil heater simultaneously being that they share a common flue?

Thanks for any suggestions,
Jason


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## TreeTangler (Dec 18, 2013)

Although it is done more than it should be, it carries the potential to be very dangerous to your family. Make sure your flue is clean and safe and check it often. Please make sure that your home is equipped with working smoke detectors and carbon monoxide detectors.


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## jpmako (Dec 18, 2013)

TreeTangler said:


> Although it is done more than it should be, it carries the potential to be very dangerous to your family. Make sure your flue is clean and safe and check it often. Please make sure that your home is equipped with working smoke detectors and carbon monoxide detectors.




Thank you for the advice. I cleaned the chimney when I was there in the spring. I have also installed new smoke detectors as well as carbon monoxide detectors in the house. I know that this set-up is not in any way ideal but do you think it is safe to run the stove while the heat is on or will this be a problem? Next year I am going to have the chimney completely redone with two flues to remedy this situation. I am also planning on removing the insert upstairs and replacing with a Jotul F55 wood stove (separate chimney).


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## shutup-n-cut (Dec 18, 2013)

I highly doubt that it is a legal installation but honestly that would be just a guess.
Local building codes also vary so what works in one place is no good in another.


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## jpmako (Dec 18, 2013)

shutup-n-cut said:


> I highly doubt that it is a legal installation but honestly that would be just a guess.
> Local building codes also vary so what works in one place is no good in another.



As far as I know this set-up was grandfathered and is legal.


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## XSKIER (Dec 18, 2013)

jpmako said:


> As far as I know this set-up was grandfathered and is legal.



As long as your insurance is good to go, let her rip. No cents trying to reinvent the wheel.


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## idahohay (Dec 18, 2013)

1. It is possible that both units would draft adequately.

2. Yes you should worry.


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## shutup-n-cut (Dec 18, 2013)

Grandfathered in works. Probably be frowned upon doing it like that today.
If it ain't broke don't fix it.


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## TreeTangler (Dec 18, 2013)

There really isn't a legal issue, you're not going to get fined for a setup like this. I'm really not sure who is "grandfathering" the setup. The issue is with the possibility for the flue not to draft one of the appliances or the chimney plugging and either one of these situations dumping toxic fumes into the house. As far as insurance goes, i have a hard time believing that they would be ok with it.

Either way, the choice is yours. Will it work? Chances are it'll work fine for heating as it is done a lot by folks who don't know any better. The problem with this setup that it drasticaly raises the chances that something can go wrong that would put you at risk.


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## jwilly (Dec 20, 2013)

In Maine if the installation was in place prior to 1998 it is "grandfathered" 1999 and up it is not legal.

Oil fired appliances produce sulphuric acid in the exhaust and this can combine with the woodsmoke and create an extremely corrosive mix that can eat up the masonry joints in the chimney.


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## Whitespider (Dec 20, 2013)

Oh boy... I've run multiple appliances, using multiple fuel sources, into a single brick 'n' mortar chimney all my life... and I'm still alive. Those "codes" are the result of a small percentage of simpletons that managed to burn their house down (or suffocate their family)... it's nothing more than government doin' the, _"we're gonna' protect you from yourself"_ thing.

As long as you're willing to be aware, attentive and vigilant you'll be fine... lose the vigilance and you increase the chances of problems.
It's all a matter of taking responsibility... you're either aware, attentive and vigilant for yourself and family, or you are not and expect someone else to keep you safe. Life ain't safe, or fair... only you can make it into what you want it to be.

Is running multiple appliances, using multiple fuel sources, into a single flue the absolute safest way to do things?? Well... hell no it ain't‼
But it's a damn sight safer than drivin' to the local grocery store... just put it in perspective man.


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## blackdogon57 (Dec 20, 2013)

Vigilance would be getting something like that fixed before it burns your house down and kills you and your family. Carelessness would be letting it ride because by fluke it hasn't harmed anyone yet.


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## Oliver1655 (Dec 21, 2013)

Many are the houses I have been in over the years which have shared flues. A cook stove on one side of the wall & a wood/oil stove on the other side is one common arrangement. Another was having wood stove on one side & the propane hot water heater on the other side. How many of us have been in old farm houses with the snap-in flue covers on chimneys where some of the openings have been closed off? The key was they would have a hot fire to get enough heat to warm the drafty/poorly insulated houses & regularly clean the chimney.

Do I have a shared chimney? No. The way newer homes are setup/spread-out helps to eliminate shared chimneys.


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## DavidBrown1212 (Dec 21, 2013)

I run a wood stove and oil furnace into the same flue. I have my furnace set at 73 all the time. It only kicks on if my fire goes out. I have a cut off switch in the basement so the oil furnace can be cut off while i am building a fire and gsetting a draft started. Your furnace should have a little automatic draft control, which is the round flapper on the oil exhaust pipe. It has adjustable werights on it. It purpose is to maintain a constant draft pressure which helps keeps your oil furnace burning with right fuel/air mmixture when outside pressures may be fluctuating (windy nights). When you got a real ggood fire going, the fire will pull this flap open, reducing velocity and temp in the chimney, which may llead to more creasote condensating on your chimney. I put a rock on the flapper while the chimney is warming up, a good 2 hours, this does not completly solve the problem, but i feel it a good middle ground.


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## Whitespider (Dec 21, 2013)

blackdogon57 said:


> *Vigilance would be getting something like that fixed...*



Fixed?? It's only possible to fix something if it's broken in the first place.
It's been done that way for much longer than it ain't been done... and it don't present near the danger you've been led to believe.
I live in Iowa... I have a greater chance of getting bitten by a shark.

This house has stood for over 100 years with a shared flue... with as many as 4 appliances sharing it.
My gosh... how did people survive before all these safety codes to keep them safe?? Listening to some of you... we all should'a died before the age of three. It took me over two hours to remove or disable all the stupid "safety" crap on the last grass cuttin' machine I bought... in over 50 years of cuttin' grass I've never been injured. See, about the time I was in kindergarten, dad pointed at the spinning blades and told me not to put my fingers in there. About that same time he also taught me how to swim... took me out on the lake and tossed a float off one side of the boat, and me off the other... then he stood there with his arms crossed and watched me "learn"... ain't never once in my life wore a "life" preserver jacket, yet I'm still alive.

There's even a sticker under the hood of of my wife's van warning of moving parts with a picture some cartoon character getting chopped to bits.
C'mon... really?? Are people so stupid, so unwilling to take personal responsibility that there has to be a sticker like that?? Back in-the-day dad taught me not to touch the car brakes on a snowy morning until after you got moving... just slip it into gear with your foot off the brake. The reason was your brakes could take a set and make difficult to get moving 'cause they'd be dragging... but now the "safety police" insist every car have the shift lever locked in park until you step on the brake. Really?? Why?? Because some idiot backed through his garage door I have to pay for that ******** I don't want on every car I buy now.

It ain't the job of government to keep us safe from ourselves... the only thing that's been accomplished by the "safety police" is to raise a nation of mindless idiots and wusses. For some reason now-a-days people expect to be "safe" at all times... they somehow believe they have a "right" to be 100% safe at all times... and they somehow believe government and all those safety codes provide that. Every time some bumblin' idiot injures himself we have to have a new rule, law or code adding yet another worthless expense to our lives.

So I ain't buyin' that my flue needs to be "fixed"... but I can think of a lot of things that should be "fixed"...
And I sure in the hell ain't buyin' that a "safety" code somehow makes me "safe"...
If you feel better, if it helps you sleep at night to follow some arbitrary, one-size-fits-all "safety" code or rule... then by all means you should do so. But you have no "right" to expect me to believe as you do... and you have no "right" to judge me if I don't. 
*


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## DavidBrown1212 (Dec 21, 2013)

I got my wood stove semi shrouded in sheet metal and the shroud ducted into the air handler, so you can have that heat distributed evenly.


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## olyman (Dec 21, 2013)

ive been running the water heater, [gas], and my woodstove, in the same chimney for over 40 yrs.................think about this. yes,ng gases will cut the "creosote" coating off of the inside of the chimney during the summer. i then clean the chimney just before i start the wood burner.........then the chimney recoats itself during the winter...i burn dry wood only...and the buildup from the year before,,when i clean it in the fall,,near falls off........the inside of my chimney, is 10 inch. that will carry more than one "appliance"!!!!!!!!!!!!!!!!!!!!!!!!!


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## AIM (Dec 21, 2013)

OK I have to ask. WHY should you not use the same chimney?? I have seen this comment a zillion times on here but never knew the why.
Don't just cite me codes. I could care less about the codes. I want to know the science behind the so called dangerous setup and why you shouldn't do it..


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## Whitespider (Dec 21, 2013)

The inside of my chimney is 10×14... thats the equivalent of a 14 inch round pipe, or five 6 inch pipes.
There's a reason why that chimney was built like that... it was intended to be used with multiple appliances.
It is shared by a propane fired furnace, propane fired water heater and the wood furnace. I've never needed to clean it, the propane water heater exhaust causes all the "stuff" to flake off over the summer... and the draft is strong enough that most of that "stuff" flies out the top, very little falls to the bottom.



AIM said:


> *OK I have to ask.* WHY*...*


There are several reasons for the code...

Sharing a chimney may reduce the draft to each appliance... but what if there's enough draft??
A second gas or oil appliance allows cool air into the chimney, which can cool the wood combustion gases promoting creosote formation... so why is a barometric damper allowed??
The combination of *oil* and wood soot forms a corrosive compound that can attack and weaken mortar... personally, I've never seen that happen, so I'm guessin' not all mortar is created equally??
*Oil* soot can ignite at a much lower temperature than creosote, thereby increasing the chance of a chimney fire... but, nothing can eliminate the chance of a chimney fire, can it??
Some gases release a lot of water during combustion (such as propane), which can also cool gases and promote creosote formation... but what if the chimney is warm enough, such as mine that runs up through the center of the house??

So yeah, the "code" is designed to protect the person who ain't smart enough to inspect and maintain his chimney... of course, before the code, most everybody was smart enough to inspect and maintain the chimney (personal responsibility). We have the code because some fool ignored his chimney, and because of him... we all pay. We are protected from ourselves.

Oh... I forgot to mention that a properly maintained and operating oil-fired appliance makes very little, if any soot deposits in a properly designed and operating chimney.
As with a lot of those "safety" codes, they address the "what if, worse-case"... they really don't do much to make us safer... they just protect the idiot from himself.
*


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## Rburg44 (Dec 21, 2013)

DavidBrown1212 said:


> I run a wood stove and oil furnace into the same flue. I have my furnace set at 73 all the time. It only kicks on if my fire goes out. I have a cut off switch in the basement so the oil furnace can be cut off while i am building a fire and gsetting a draft started. Your furnace should have a little automatic draft control, which is the round flapper on the oil exhaust pipe. It has adjustable werights on it. It purpose is to maintain a constant draft pressure which helps keeps your oil furnace burning with right fuel/air mmixture when outside pressures may be fluctuating (windy nights). When you got a real ggood fire going, the fire will pull this flap open, reducing velocity and temp in the chimney, which may llead to more creasote condensating on your chimney. I put a rock on the flapper while the chimney is warming up, a good 2 hours, this does not completly solve the problem, but i feel it a good middle ground.




Can u give me a lil more info on this flapper thing this is my set up and would like to know more thanks


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## jpmako (Dec 21, 2013)

Wow,

Great responses. It is encouraging to see some others with the same basic set-up that don't have any problems. I am very vigilant with cleaning the chimney as well as inspecting for problems. I am assuming that the previous homeowner used this set-up without having any issues, but am unsure if he used both appliances at the same time or used the wood stove only as a back-up source of heat. Anyway I am going to get a digital CO detector and place it in the basement to compliment the two upstairs that I installed by the bedrooms. I also have two fire extinguishers in the basement as well as two upstairs. I don't anticipate having any problems but would like to be prepared to deal with anything should the need arise. Should a problem occur I will put the skills that I have acquired in the last 10 years as a firefighter to good use.
Thank you all for sharing your knowledge and hopefully I can use this set-up without issue for the remainder of this year.


Jason


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## NSMaple1 (Dec 21, 2013)

My old oil/wood boiler had two flue pipe outlets on it. They went into the same flue. The only condition was that the oil had to T into the chimney above the wood.

Looks like that's what you've got going on there, so I think you're good to go.

Would definitely keep an eye on things though, and keep your detectors in good order. Both my flue pipes had barometric dampers in them - so I would get some creosote buildup where the oil pipe T'd in from the fresh air being sucked in through the oil baro. Not major, and I swept 3-4 times a year so it was a non-issue. That was installed, to code, by pros, 18 years ago. Your jurisdiction may be different though.

I had a 30' stainless chimney though, so had lots of draft. How tall is your chimney?


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## DavidBrown1212 (Dec 21, 2013)

AIM said:


> OK I have to ask. WHY should you not use the same chimney?? I have seen this comment a zillion times on here but never knew the why.
> Don't just cite me codes. I could care less about the codes. I want to know the science behind the so called dangerous setup and why you shouldn't do it..



The smaller the the chiminey the faster it warms up, the easier it is to mmaintain a hot fast upward draft.

If you have multiple units on one flue the draft of one appliance may require a draft of one velocity, and the others require different velocities


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## CTYank (Dec 21, 2013)

Two important factors:
1) Some code officers require flue to handle rating of all appliances connected. I.E. 180 KBTU/h furnace & 50 KBTU/h for flue specs. Always seemed pretty fuzzy to me. More relevant to me: simultaneous startup of all appliances should not have discharge into house. All exhaust should be drawn out.
2) Each connected appliance should have throttled connection. IOW none have an open inlet; consider a fireplace sharing a chimney with a furnace- draft could be insufficient for furnace. Gas furnace likely will need damper in flue connection- has worked for me- they generally have way excessive draft.

Certainly not the end of it. Just looking at sharing.


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## Oliver1655 (Dec 21, 2013)

The barometric damper is a specialized "tee" normally found in the 6" stove pipe between the stove & flue. It is recommended to be at least 18" from the stove. It has an adjustable weighted door which will open allowing air to enter the chimney while bypassing the stove during high winds. If you don't have one installed real high winds can create a vacumn in your chimney system drawing extra air into the stove. This can cause excessive heat and allow the winds to draw flames from the stove into the chimney which can cause a chimney fire. It also helps the stove to maintain a steady draft/heat.

They normally sell for $40-50. Sounds expensive but is really pretty cheap insurance.


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## haveawoody (Dec 21, 2013)

Well thinking about the oil furnace and it's direct air flapper in the house I would never run the woodstove on that system.
Just think of it you have a ripper fire going in the woodstove all is well the wind picks up and forces flaming air down the chimney right out the point of least resistance the oil flapper.
A normal woodstove can handle that sort of event in it's firebox and since it has a no pressure release stack effect it's rare to see happen, but flame going into the oil furnace or out the flapper in a similar event that now has a pressure release area would make for a bad day.

Old school sometimes isn't a good thing.
IMO if you have room in the chimney put another flex pipe up for the woodstove and remove the T and make the oil furnace connection direct to it's line also, if no room then new stovepipe dedicated to the woodstove all the way up and out a new location.


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## NSMaple1 (Dec 21, 2013)

If the wind is sucking flames up the chimney from the wood stove, how can it push them out the oil pipe?

I have had that exact thing happen to me on my old setup (gusts of wind sucking fire out of the wood side), and nothing ever took a turn into the oil pipe. Straight up it will go.


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## GVS (Dec 21, 2013)

I'd run either, one at a time.NEVER both at the same time.The draft of each could be so different,one from the other. No telling what would happen when the stove door was opened to load or check while the oil burner was runing full tilt.I absolutely wouldn't do it.Those that say all is good by doing it,let them take the responsibility.There won't be many takers!


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## artbaldoni (Dec 21, 2013)

Had this setup, wood boiler and oil boiler. I would sometimes get backdraft from the oil side into the wood stove. It may have had something to do with the 8"x8" flue size. The wood fire was nearly out or just starting and the water temp was low enough for the oil burner to kick in so both units were trying to exhaust at the same time. I agree that if you used only one at a time you should have no issues.


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## Whitespider (Dec 21, 2013)

As a bachelor I lived in an old dilapidated, drafty, two story farm house with an oil-fired furnace in the basement (a converted coal burner). The brick 'n' mortar chimney was on an outside north wall. The 10 inch flue pipe came off the furnace for a couple feet to the barometric damper, then ran horizontally about 10 feet to the chimney. I set a barrel stove next to the furnace and ran the flue pipe just past the barometric damper and *Y*'d into the oil furnace flue pipe... about 8 feet from the chimney.

When it was cold that old oil furnace started/stopped 3-4 times an hour while the barrel stove was runnin' hot 'n' heavy at the same time. I had the loading door open on that barrel stove hundreds of times when the oil furnace was either running or starting-up. I don't remember ever having anything "reverse" direction in either appliance... I don't remember any draft problems at all. Obviously the oil furnace was getting enough draft because the barometric damper was always open some... even with the extra 6 inch stove pipe *Y*'d into it.


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## NSMaple1 (Dec 21, 2013)

Well, I ran my setup for 17 years. Installed to code, by pros. There were lots of times the boiler oil side would cut in when there was a wood fire going in the other side of it, when there was too much heat demand for what the wood side was putting out. Which is the way the boiler was designed to work. As long as you've got adequate chimney draft, things should be good. How long has it been setup & running like this? That's likely your proof.

Out...


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## haveawoody (Dec 22, 2013)

NSMaple1,

Well not much pressure difference between flame going up the chimney and out the oil flapper.
When fires are starting or winding down in the woodstove the chimney effect isn't much so a good gust of wind can easily push flame back down.
The oil furnace would be 100% safe to run on that setup since the oil flame pressure wont allow backdraft on the flapper.
IMO though I would never run both at the same time and if I was running the woodstove I would be very careful about doing it on very windy or gusty days.
Really best solution is to bite the bullet and migrate the woodstove to it's own chimney or at least own flex in the chimney, both units will be more efficient and both much safer.


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## Whitespider (Dec 22, 2013)

There's that word again... "safer".
Safer than what?? Safer than running them both in the same flue?? Well... just how "unsafe" is that?? It's likely "safer" than a lot of everyday things you do.
Buying your firewood is a damn sight "safer" than goin' out in the woods and felling your own trees... how many of you cut your own firewood?? Can anyone tell me the odds of being injured or killed while cutting firewood versus the odds of being injured or killed by running two appliances in the same flue?? Anyone??
Sure... some things increase the odds... but you do that every day also...
Can anyone tell me the odds of burning your house down using that damaged drop cord (that you repaired with black tape) versus the odds of a chimney fire burning your house down?? Anyone??

Rules, regulations, laws, codes and whatnot do not, can not keep you "safe"... they never have, they never will. At best, they protect the fool from himself... and believe me, the fool will still find a way to be foolish. Just being alive is a "risk"; you risk losing your life every second you're alive... but without risk there can be no gain. There ain't a damn thing government and it's rules can do to reduce the risks of life... only a fool would believe it could. Knowledge and awareness is the real power... something all these "safety" rules have caused people to lose.

The OP asked about an existing set-up. An existing setup they may have been there for decades, yet some are convinced the first time he fires it up his house will be reduced to a pile of ashes... or worse. Some are saying it will be "unsafe" to run both at the same time... when likely both have run at the same time safely for decades.

Would I advise someone to do a new install like that?? No, I would not.
Would I advise someone to *not* do a new install like that?? No, I would not.
I would tell them to check local codes first, I'd make them aware of *possible* problems, issues and whatnot, I'd tell them to do their own research on possible dangers and the causes... and let them make their own call.

@jpmako 
You, and only you, are responsible for you and your family. You, and only you, can make the call on this one. Do not let anyone else make this decision for you... not me, not anyone on this board, and certainly not government (although possible fines and whatnot, if there are any, should enter into the decision making). If you decide to use the existing set-up... well... don't be a fool, educate yourself on the possible problems, issues, dangers and how to minimize them. Keep a close eye on things (especially at first) until you get a "feel" for how the set-up performs, keep things properly maintained, and don't ever become complacent... don't ever become complacent about anything in life, the dangers don't begin and end with your chimney. And above all, never forget that you, and only you, are responsible for you and your family.
*


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## jpmako (Dec 22, 2013)

Whitespider said:


> There's that word again... "safer".
> Safer than what?? Safer than running them both in the same flue?? Well... just how "unsafe" is that?? It's likely "safer" than a lot of everyday things you do.
> Buying your firewood is a damn sight "safer" than goin' out in the woods and felling your own trees... how many of you cut your own firewood?? Can anyone tell me the odds of being injured or killed while cutting firewood versus the odds of being injured or killed by running two appliances in the same flue?? Anyone??
> Sure... some things increase the odds... but you do that every day also...
> ...




Very well said. As an adult I take total responsibility for my decisions as well as my personal safety and that of my family. Like I said earlier I am a Volunteer Firefighter so that in itself provides many opportunities for me to either get injured or dead, but I continue to do it. A lot of things that I do are dangerous but I enjoy doing them. I will be trying the existing set-up when I get into the house and will keep a watchful eye on how things go. I would assume that this was used this way before the way that it is without issue. Hopefully I live to report back and let everyone know that everything is okay and it all worked out.


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## nk14zp (Dec 22, 2013)

What part of Maine are you moving to?


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## jpmako (Dec 22, 2013)

nk14zp said:


> What part of Maine are you moving to?


 Outside of Bucksport.


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## DavidBrown1212 (Dec 22, 2013)

haveawoody said:


> NSMaple1,
> 
> Well not much pressure difference between flame going up the chimney and out the oil flapper.
> When fires are starting or winding down in the woodstove the chimney effect isn't much so a good gust of wind can easily push flame back down.
> ...


 This is not the way the flapper works. It only allows one way flow into the flue. In no way could flames be pushed out of it. But I do agree, having separate liners for each appliances would be the best solution as far as safety and performance.


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## artbaldoni (Dec 22, 2013)

My setup worked for 10 years. Just would get some smoke out of the wood side occasionally when the oil kicked on. I didn't really see a safety issue, only a too small of a flue issue for both, but only under certain circumstances and for a very short period of time when the oil first kicked on.


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## farmer steve (Dec 22, 2013)

Hi Art.


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## artbaldoni (Dec 22, 2013)

Hey FS. Did it make 70 out your way today?


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## DavidBrown1212 (Dec 22, 2013)

I used to have separate liners in my old house, but now i have a two into one setup. More creosote build up, but i ahe not changed it. Maybe someday.
,


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## Franny K (Dec 22, 2013)

Whitespider said:


> As with a lot of those "safety" codes, they address the "what if, worse-case"... they really don't do much to make us safer... they just protect the idiot from himself.
> *


A lot of the reason for the codes is that real estate can be bought and sold. I am amazed how stuff changes though In 1993 I needed an 8x12 flue min but apparently now you need six inch liner all the way up. It was in a fireplace with the stainless steel insert piece.

Post 1 doesn't state if the flue is lined or how high from thimble to top does it?


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## 1project2many (Dec 22, 2013)

> Can anyone tell me the odds of being injured or killed while cutting firewood versus the odds of being injured or killed by running two appliances in the same flue?? Anyone??



There are situations where you are actively involved and situations where you are passively involved. Burning wood is one where you are frequently passively involved. You cannot actively monitor anything while sleeping, or while away from the house. Because of that I tend toward following code, even if it does seem unlikely that I'll have any issues. There's no guarantee everything will be just fine but if the code is based on real problems, the odds are a little more in my favor if something goes wrong.



> You, and only you, are responsible for you and your family. You, and only you, can make the call on this one. Do not let anyone else make this decision for you... not me, not anyone on this board, and certainly not government (although possible fines and whatnot, if there are any, should enter into the decision making). If you decide to use the existing set-up... well... don't be a fool, educate yourself on the possible problems, issues, dangers and how to minimize them. Keep a close eye on things (especially at first) until you get a "feel" for how the set-up performs, keep things properly maintained, and don't ever become complacent... don't ever become complacent about anything in life, the dangers don't begin and end with your chimney. And above all, never forget that you, and only you, are responsible for you and your family.



Exactly! Asking a forum why or why not as part of doing research is perfectly acceptable. Deciding it's ok "because the guys at the forum said so" is as bad as saying "I dunno why the building code says do this, but I'm going to do it."

There is a potential issue with inertia if the gasses in the stack don't want to increase velocity fast enough to prevent exhaust from the forced draft appliance to seek exit through the natural draft appliance (wood stove). Putting the wood stove fresh air intake outside the house would be worth considering.


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## haveawoody (Dec 23, 2013)

DavidBrown1212,

I have a similar flapper on my oil furnace and used to watch it flap around just from wind gusts when the oil furnace wasn't on.
I heat with just wood now but the oil furnace remains with it's flapper insulated over and the main disconnected on the oil furnace.
Although I love to heat with wood at some point in the future if I ever sell the place the people might not so the oil furnace stays.

On normal operation the flapper runs quite well on an oil furnace although I have seen giant smoke billows exit mine when the oil furnace backfired.
With a second fire source on the same line and a direct connection via T to that flapper it's just an invitation for fire to head that way.

Not saying it would ever happen and in reality probably very low odds of it, but if you burn firewood long enough who hasn't seen a backdraft happen even in a woodstove with a single direct chimney.


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## haveawoody (Dec 23, 2013)

Whitespider,

Life is all about risk and reward.
I'm not saying he should run out and change the system for fear of it causing a fire, it's just not a good setup for a woodstove.
All about risk though and really it's very low risk.

Most people end up doing the duct tape repair now and then on something to get it working but long term repairs the duct tape usually gets put away.
Repairs on things that shoot fire up a house duct tape sorts or repairs seldom work properly.

For me it's something I would correct ASAP, worrying about that bad would have me putting in chimney pipe.
We all have risks in life but it's nice to make them as small a risks as possible.


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## farmer steve (Dec 23, 2013)

artbaldoni said:


> Hey FS. Did it make 70 out your way today?


 no Art, all the people in cumberland co. were hoggin all the heat. only hit 67.


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## Whitespider (Dec 23, 2013)

1project2many said:


> *There are situations where you are actively involved and situations where you are passively involved. Burning wood is one where you are frequently passively involved.*



I don't agree with your analogy... I guess it's perspective and how you define the words.

When you fell a tree, you "actively" do the cutting, but once it starts falling you are only "passively" standing under it... you "actively" cause the action, but you have no input once it begins, you can only "passively" watch the result.
Wood burning may "allow" you to be "passive" at times of your choosing, but unlike the above example, you always have the option to become "active"... with wood burning you "actively" cause the action, and you have the option for input at any time during the result, including stopping the action.

You can be killed or injured while felling a tree because you are "passively" involved (you can't stop the action)... whereas you can save your life or property during a wood-fired appliance malfunction because you can be "actively" involved (to use a cliché, you can throw water on the fire).
*


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## jpmako (Dec 23, 2013)

Some good news,
I have just been in contact with a family friend whom spent a lot of time in the house during the previous winters.
He said that both the wood stove and the oil furnace were both used together all winter. He also said that the flue has the capacity for both appliances and that he remembers that the only time that the wood stove was not being used was when it was full and needed to be cleaned out.
This at least puts my mind at ease for this year.

Thank you for all of the replies


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## Stoviser (Sep 3, 2016)

jpmako said:


> We are moving to our house in Maine after the new year. The current set-up is, in the basement an oil heater and our Cawley 600 wood stove share the same flue. Upstairs we have an older insert with a blower. Although the set-up in the basement is "Grandfathered", I know that this is not an ideal. Since we are moving to the house during the winter I have some questions regarding safe burning practices. Being that the house is vacant, we turned the heat to 55 degrees to save on heating oil. When we arrive I will obviously turn the heat up to make the house comfortable. Since we have a stove in the basement and an insert upstairs, I would like to primarily heat with wood.
> 
> My questions are:
> 
> ...



The first thing you should do is evaluate the age of the chimney. Older chimneys can have loose bricks that can leak smoke and hot embers into walls or attic spaces, not to mention Co2 which can be deadly. You could burn your house to the ground or suffocate the first time you use your stove without taking your time and setting things up properly. I personally had a ceramic chimney in a house I owned and single wall stove pipe was inserted from the bottom of the chimney one length at a time and connected together with sheet metal screws. I was lucky in my case because I could ad sections because my chimney was anchored between floor joists i the basement. This was my only source of heat I used for many years.
You can do the same thing by adding another hole in your chimney directly across from your furnace so that you can remove the furnace vent temporarily to access the sheet metal elbow of the new chimney to drop in a flexible chimney liner from the roof or single wall pipe from the roof. I've never dropped in single wall piping from the roof connected together which could be very difficult but you could try chimney liner that comes in 25-30 foot lengths that could attach easily to the stove outlet pipe. Whatever you use you need to buy a chimney cap to keep rain out and to secure the other end of the liner. Just a little work to make it all worthwhile


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## olyman (Sep 3, 2016)

Stoviser said:


> The first thing you should do is evaluate the age of the chimney. Older chimneys can have loose bricks that can leak smoke and hot embers into walls or attic spaces, not to mention Co2 which can be deadly. You could burn your house to the ground or suffocate the first time you use your stove without taking your time and setting things up properly. I personally had a ceramic chimney in a house I owned and single wall stove pipe was inserted from the bottom of the chimney one length at a time and connected together with sheet metal screws. I was lucky in my case because I could ad sections because my chimney was anchored between floor joists i the basement. This was my only source of heat I used for many years.
> You can do the same thing by adding another hole in your chimney directly across from your furnace so that you can remove the furnace vent temporarily to access the sheet metal elbow of the new chimney to drop in a flexible chimney liner from the roof or single wall pipe from the roof. I've never dropped in single wall piping from the roof connected together which could be very difficult but you could try chimney liner that comes in 25-30 foot lengths that could attach easily to the stove outlet pipe. Whatever you use you need to buy a chimney cap to keep rain out and to secure the other end of the liner. Just a little work to make it all worthwhile


really?? a three year old post???? know how many past members are no longer here????


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## ChoppyChoppy (Sep 3, 2016)

Co2 is not deadly, you meant CO, Carbon Monoxide.


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## Whitespider (Nov 18, 2016)

Talk about resurrecting old threads...
I just got 2 "likes" on this thread today... whatsup with that??
*


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## olyman (Nov 19, 2016)

Whitespider said:


> Talk about resurrecting old threads...
> I just got 2 "likes" on this thread today... whatsup with that??
> *


 made sure, your still alive!!!!


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## woodfarmer (Nov 20, 2016)

In case anyone is still interested, you used to be able to install an oil appliance and a wood burning appliance on the same floor into the same chimney flue as long as the oil vent was above the wood.
Now each appliance requires its own flue.


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