Sealing wood stove flue pipes

[mickri]

I will be reinstalling the Arrow 1800a wood stove in my house over the next week or so. I bought single wall flue pipe from Lowes. Put the sections together and noticed a small gap in places where the pipe sections join together. I don't remember seeing gaps like this in the flue pipes in my previous home. Wondering if these gaps should be sealed.

I did a search and found threads both here and other places online with conflicting info on whether to seal or not seal and what to use for a sealant if you do seal.

The stove sits in a surround that looks like a fireplace that was never finished. There is a typical clay flue pipe that will hold the single wall flue pipe I got from Lowes. There is a 45 degree bend coming off the top of the stove that fits into another 45 degree bend that fits into the single wall flue pipe. No way to get around having bends coming out of the stove. I might be able to make the bends at 22.5 degrees.

Do I need to seal these gaps. If so what should I use as a sealant.

 

[bholler]

I will be reinstalling the Arrow 1800a wood stove in my house over the next week or so. I bought single wall flue pipe from Lowes. Put the sections together and noticed a small gap in places where the pipe sections join together. I don't remember seeing gaps like this in the flue pipes in my previous home. Wondering if these gaps should be sealed.

I did a search and found threads both here and other places online with conflicting info on whether to seal or not seal and what to use for a sealant if you do seal.

The stove sits in a surround that looks like a fireplace that was never finished. There is a typical clay flue pipe that will hold the single wall flue pipe I got from Lowes. There is a 45 degree bend coming off the top of the stove that fits into another 45 degree bend that fits into the single wall flue pipe. No way to get around having bends coming out of the stove. I might be able to make the bends at 22.5 degrees.

Do I need to seal these gaps. If so what should I use as a sealant.

Typically no joints are not sealed. If there are large gaps try running a screw through them to tighten them up

 

[stoveliker]

There is a typical clay flue pipe that will hold the single wall flue pipe I got from Lowes.

Maybe I'm misunderstanding, but are you putting single wall stove pipe into the clay flue?

 

[bholler]

Maybe I'm misunderstanding, but are you putting single wall stove pipe into the clay flue?

I think they were talking about running it through the crock. But I could be wrong

 

[mickri]

Yes I am running the single wall pipe up through the existing clay flue. The manual for the stove specifies a 6" flue for proper draft. The manual further specifies that when routing the flue into an existing chimney flue the chimney flue can't be more than 90 sq inches. The clay flue pipe on my chimney is larger than that.

The gaps in the pipe joints are where the seams are. The gaps are larger than I am comfortable with. I could try flattening the seams to make the gaps smaller.

 

[begreen]

Is the single-wall pipe stainless steel liner, rigid or flexible? That is all that is permitted for this application inside the clay liner. Make sure the clay liner is thoroughly cleaned before installing.

 

[stoveliker]

To be clear, the stove pipe you have in the stove room cannot be used as a liner in a chimney.

Maybe this is all a misunderstanding due to choice of words - but given the safety implications, it's important to be clear.
(I didn't know HD sold chimney liner, but I checked and they do).

 

[mickri]

The pipe I bought from Lowes is for wood stoves. I had to special order it. Don't know if it is stainless steel. It is black in color. I wouldn't call it a chimney liner. It is rigid, not flexible, and easily fits inside the current clay flue. I may be using wrong terms here. The current clay flue is approximately 10"x14" inside dimensions.

 

[snobuilder]

The pipe I bought from Lowes is for wood stoves. I had to special order it. Don't know if it is stainless steel. It is black in color. I wouldn't call it a chimney liner. It is rigid, not flexible, and easily fits inside the current clay flue. I may be using wrong terms here. The current clay flue is approximately 10"x14" inside dimensions.

They recommend SS liner due to the corrosive effects of the fire. The black pipe will work but it will rust out and leak, albeit into your chimney that is a chimney with or without a metal liner. Not sure how long before it rusts out but I suspect in the long run you are better off with a $$$ SS liner right from the start
All I know is that I am venting through a 8x8 clay chimney, and it works fantastic without a liner. 10x14 is another story

 

[bholler]

The pipe I bought from Lowes is for wood stoves. I had to special order it. Don't know if it is stainless steel. It is black in color. I wouldn't call it a chimney liner. It is rigid, not flexible, and easily fits inside the current clay flue. I may be using wrong terms here. The current clay flue is approximately 10"x14" inside dimensions.

Just because something is for woodstoves doesn't mean it is meant to go inside a chimney. If it is black it is not a stainless liner and will fail quickly inside a chimney

 

[mickri]

Thanks for the info about using a wood stove flue pipe inside a chimney. Be interesting to see how long it lasts. I expect to go through about a cord of wood each winter. That is how much I used at my prior home that had similar winter temperatures to the new place.

I will see what I can do about decreasing the size of the gaps in the pipe joints.

 

[bholler]

Thanks for the info about using a wood stove flue pipe inside a chimney. Be interesting to see how long it lasts. I expect to go through about a cord of wood each winter. That is how much I used at my prior home that had similar winter temperatures to the new place.

I will see what I can do about decreasing the size of the gaps in the pipe joints.

It will most likely be pinholed at the start of the second season. The way to eliminate those gaps is by using the appropriate product for your application. I assume your "liner" is not insulated either right?

 

[mickri]

It is single wall stove pipe. No Insulation.

I live in California where it doesn't get that cold. In my prior home I would start a small fire in the wood stove in the late afternoon. Add a log or two during the evening. Never tried to keep it going all night. That would keep the great room at just over 80 degrees. My elderly mother's preferred temperature.

That home had the largest model Fischer wood stove. I made the mistake of loading the stove up once to see if it would last all night. The temp went to almost 100 degrees in the great room. There was an 8" single wall pipe, no insulation, that went from the top of the stove to the ceiling. There was a double wall insulated pipe that went from the ceiling through the attic and out the roof. No pin hole leaks in either the single wall pipe or the insulated pipe. I lived there for 7 years and have no idea how old the pipes were.

Why will the new pipe in my current home develop pin hoe leaks in one season's use? What will cause that?

 

[bholler]

It is single wall stove pipe. No Insulation.

I live in California where it doesn't get that cold. In my prior home I would start a small fire in the wood stove in the late afternoon. Add a log or two during the evening. Never tried to keep it going all night. That would keep the great room at just over 80 degrees. My elderly mother's preferred temperature.

That home had the largest model Fischer wood stove. I made the mistake of loading the stove up once to see if it would last all night. The temp went to almost 100 degrees in the great room. There was an 8" single wall pipe, no insulation, that went from the top of the stove to the ceiling. There was a double wall insulated pipe that went from the ceiling through the attic and out the roof. No pin hole leaks in either the single wall pipe or the insulated pipe. I lived there for 7 years and have no idea how old the pipes were.

Why will the new pipe in my current home develop pin hoe leaks in one season's use? What will cause that?

The fact that it is inside a chimney where condensation will be trapped. Combine that with small amounts of residue left in the chimney and regular steel won't last long at all

 

[mickri]

Thanks for the explanation.

 

[wagne223]

Another issue with using uninsulated pipe is creosote build up.
Using a classic stove, it will probably burn "wet" wood and if you don't need a lot of heat, you may be tempted to smolder it.
Common burning practice on older stoves.
Combined with uninsulated pipe this could be a creosote maker.

Creosote leads to chimney fires. Which brings me to my second point.....

I am not a pro, however I do not believe stove pipe is rated for use as a chimney liner. Therefore the installation is not up to code.
If the install is not up to code, it is highly likely your insurance company would not pay for damages related to a fire caused by using your stove.

Be careful!

 

[bholler]

Another issue with using uninsulated pipe is creosote build up.
Using a classic stove, it will probably burn "wet" wood and if you don't need a lot of heat, you may be tempted to smolder it.
Common burning practice on older stoves.
Combined with uninsulated pipe this could be a creosote maker.

Creosote leads to chimney fires. Which brings me to my second point.....

I am not a pro, however I do not believe stove pipe is rated for use as a chimney liner. Therefore the installation is not up to code.
If the install is not up to code, it is highly likely your insurance company would not pay for damages related to a fire caused by using your stove.

Be careful!

Very well said