want to add wood stove to oil furnace chimney

[mrfischy]

A couple years ago the house where we live got new ss chimney liners. A chimney that had an oil/wood combination furnace in the basement and a wood cookstove in the first floor kitchen became a single flue for the oil furnace alone. The installer was a stickler for standards and would not hook it all back up as it was. Dual and multiple installations are common here and there are other installers who do them. We didn't own the place.. it wasn't our choice. Now we do own it (yeah) and we want, at least, to get the cookstove going to heat the kitchen. We don't need a furnace going anyway and would end up using it a lot less. This is because most of our time and activity is in a separate side of the house that has only wood heat. We have extra rooms that we hardly use in winter unless we have guests... except the kitchen..

So.... What are the issues here?

Is it safe to use the single ss flue for oil (basement) and wood (first floor)

Can we add a 'Tee' into the existing ss flue and what does it take to do this?

What to do about cleanout from the wood ... if we get that far

What is required to accomodate a powervent system for the oil furnace ...as an option to the dual hookup?

 

[Mike Wilson]

Is it safe to use the single ss flue for oil (basement) and wood (first floor)

No.

Can we add a 'Tee' into the existing ss flue and what does it take to do this?

No.

What to do about cleanout from the wood ... if we get that far

You won't.

What is required to accomodate a powervent system for the oil furnace ...as an option to the dual hookup?

Have your oil service tech tell you if he can install a direct vent for your boiler before you try to put the wood burner on the SS liner. Then it's not a dual hookup anymore.

-- Mike

 

[perley03]

I went through this deal when we bought our house and was insurance shopping. Most insurance companies will not insure your home if you have 2 devices hooked up to a single flue chimney. When we bought our house, it appeared to have both the hot air furnace and woodstove hooked up, and was denied coverage by several insurance companies. Upon further investigation, I found out that our chimney was a dual flue chimney, and each device was hooked up separately to its own flue. I talked to the local fire inspector and he said the main concern is when you have both devices going, it does not maintain an adequate draft, causing CO and other gasses to build up in your home. Also without a sufficient draft, creosote will build up, causing a chance of chimney fire.

 

[mrfischy]

OK, I think I've got it... not a consensus entirely, there seem to be some situations where wood and oil going into the same flue get some kind of approval, but it is very limited and most say, just don't do it. In any case, it is not our situation. If there is a rule, it is that the wood burner should be on a separate flue. On to the next query about venting the oil furnace by another means. Thanks, I appreciate the quick, pointed response.

 

[JimWalshin845]

WHEN you have the FIRE... your insurance company will probably say..."NOPE....NAY....NIX.....UH-UH.... DEFINITELY NOT.... We AIN'T gonna PAY" :shut: :sick: :-S

 

[Mike Wilson]

OK, I think I've got it... not a consensus entirely, there seem to be some situations where wood and oil going into the same flue get some kind of approval, but it is very limited and most say, just don't do it. In any case, it is not our situation. If there is a rule, it is that the wood burner should be on a separate flue. On to the next query about venting the oil furnace by another means. Thanks, I appreciate the quick, pointed response.

No, there is consensus, and there are absolutely no situations where wood and oil can go through the same flue, period. Technically, my understanding is that you cannot have two different fuels on the same flue... so while it is okay to have an oil boiler and an oil hot water heater on the same flue, you can't have a coal furnace and an oil hot water heater on the same flue.

I liked the idea about direct venting the oil burner, if you can. Also, what about running two separate SS liners in your chimney?

-- Mike

 

[JimWalshin845]

[quote I liked the idea about direct venting the oil burner, if you can. Also, what about running two separate SS liners in your chimney?

-- Mike[/quote]

Yes, you can direct vent the oil/gas furnace with a power vent unit in most situations. Check with your local building enforcement.

 

[heatshrinktube]

I've had a boiler and woodstove hooked up to the same flue for 15 years with no trouble using the woodstove every weekend and day's off from work. We have CARBON MONOXIDE detector and it's never gone off except when tested. When the boiler starts I can see the damper flip open that tells me it's taking draft OK. Every draft and chimney situation is different so the general rule is not to use same flue. One of my best friends installs SS liners for a living so it helps having his advice and input. Make sure you put the woodstove thimble above the oil burner thimble if you insist on using same flue! It can be done safely if your careful and poor like me. Keep an eye on things and you'll be OK. If your poor like me and have to do things yourself to get by then you can do it.
The dudes saying don't do it are probably right unless you know what your doing and can keep an eye on things. I can't afford to build a new chimney. Our woodstove and boiler is in the utility room with washer/dryer, TV, cast iron deep sink, work shop and ground level main entrance from driveway so it gets checked all the time.
Oh, the $50 Crane boiler was 30 years old when I installed it myself 15 years ago. The guy I bought it from said he wished he had it back. His new one starts up every time you turn on the hot water. This old Crane starts, runs for a couple minutes and shuts off for hours.
The house had electric heat so I had to tear it all out and install two floors of baseboard evenings and weekends for two winters.

 

[stoveguy2esw]

virtually every manual for a wood stove i have seen states specifically and usually in bold type "DO NOT CONNECT THIS UNIT TO A FLUE SERVING ANOTHER DEVICE"

 

[BrotherBart]

Like Mike said, the manual which is the inspection bible for signing off on the wood stove installation, is going to say no.

I say no because carbon monoxide from one is going to enter the house from the connection to the other and the sleep that never ends is going to happen.

 

[nshif]

Code says a wood burning ( solid fuel ) appliance must have its own flue. there are NO exceptions

 

[heatshrinktube]

It all boils down to manufacturers having to cover their butt. There is no danger using one flue if done correctly. I agree all the manufactures tell you not to use one flue because they have to protect themselves. It can be done safely if you know what your doing. I've thought about putting in two SS liners because I've co-installed about 50 of them and know how to install them but why waste the money when everything has been fine for 15 years?
Instead of just telling you not to use one flue, I'll tell you why.
One of the dangers of using one flue is creosote build-up. If the woodstove builds up creosote and blocks the chimney flue then carbon monoxide fumes can back up into the home. Another danger is not enough draft. You would have to monitor that yourself like I do.
Like I said before, you can use one flue for two devices safely like we have for 15 years if your careful. Hopefully I've explained why you can't or shouldn't instead of just saying don't or you can't. I'm telling you the reasons why you shouldn't use one flue for two devices and how you can safely.
If you have a good brain but empty wallet you can do it safely. If you have money to burn I'll install a SS liner for you.
thefifinator

 

[nshif]

It all boils down to manufacturers having to cover their butt. There is no danger using one flue if done correctly. I agree all the manufactures tell you not to use one flue because they have to protect themselves. It can be done safely if you know what your doing. I've thought about putting in two SS liners because I've co-installed about 50 of them and know how to install them but why waste the money when everything has been fine for 15 years?
Instead of just telling you not to use one flue, I'll tell you why.
One of the dangers of using one flue is creosote build-up. If the woodstove builds up creosote and blocks the chimney flue then carbon monoxide fumes can back up into the home. Another danger is not enough draft. You would have to monitor that yourself like I do.
Like I said before, you can use one flue for two devices safely like we have for 15 years if your careful. Hopefully I've explained why you can't or shouldn't instead of just saying don't or you can't. I'm telling you the reasons why you shouldn't use one flue for two devices and how you can safely.
If you have a good brain but empty wallet you can do it safely. If you have money to burn I'll install a SS liner for you.
thefifinator

Will you also pay for the rebuild of my house when it burns down because the insurance inspector found a code violation?

 

[GVA]

Maine location. check
bad advice..... check
is this Enord?

 

[laynes69]

The problem is if the chimney would plug with creasote, then the gasses would exit the nearest path. Even though you are careful, and yes it has been done, and some people have that setup. I wouldn't take the chance of doing it. Dad ran into the problem here close to 20 years ago. Had a oil furnace with a beautiful masonary chimney and high fuel bills. He went to a 90% efficient propane furnace with the intake and exhaust outside, and this freed up the chimney for the wood furnace which is still there. There are more negatives than positives with 2 into 1 flue. I say don't do it. Plus when the woodfurnace didn't meet demand, he saved money with the high efficient furnace.

 

[heatshrinktube]

Do what you have to do to keep warm and survive safely! I'm not putting this (adding a second flue) on top of my things to do list. I'm not building a new chimney or installing new SS liners to stay warm this winter. I'm sitting right next to a nice warm stove here right next to the boiler using the same flue like we have done for 15 years. I have to put another log in the stove right now so I'll talk to you later.
Keep safe and warm this winter.
Barry

 

[heatshrinktube]

Originally thought I'd add to this thread hoping to learn more about this topic but apparently I Know more than everyone else about this and nobody has any valid response.

 

[begreen]

Show me where the stove manual recommends this. I don't see an attempt to learn anything. Instead I see an attempt to justify a basic safety and code violation. What you do in your own home is your call. As the saying goes "Anything is possible if you don't know what you are talking about."

NAFA 31 Oil burner code Chapter 6 Venting of combustible fuels

6.5.1.9
Solid fuel burning appliances shall not be connected to a chimney flue servicing another appliance burning other fuels unless specifically listed for such connection

6.4.1.4
Connectors serving appliances under natural draft, shall not be connected into any portion of a mechanical draft system

 

[ChrisN]

Barry, If you set your system up like that its your business, but to recommend the set-up to others is reckless at best. It's illeagal for a reason. People have died using a shared flue and this has been pointed out to you repeatedly. Please don't blow in here, making absurd recommendations. Your reckless, thoughtless advice could get a novice burner, who doesn't know any better, and his family killed.

 

[BrotherBart]

Originally thought I'd add to this thread hoping to learn more about this topic but apparently I Know more than everyone else about this and nobody has any valid response.

You can't learn more about this topic. You obviously know more about it already than the professionals that wrote the International Mechanical Codes, The National Fire Protection Association Codes and every stove and chimney product manufacturer in the country.

Give it a break.