I think my chimney needed to be cleaned.....

[Aerindel]

So, where it passes through the wood (or laminate) floor, is it cool enough to put your hand on the pipe?

Yes. At its hottest its still below 200º

And it's just a layer of boards over the top of a block of concrete with a 1" air gap between it and the pipe.

If I had planned ahead I would have cast the concrete an inch higher so to be flush with the flooring, but I didn't so I ran the flooring boards over the top of it so there wouldn't be an inch lower 'hole' in the floor where the concrete was. Upstairs the concrete is flush with the flooring so there is no wood near it.

 

[Cabin Fever]

I hope that 1" air gap is enough space. If you ever did have a chimney fire, that well casing will likely be glowing red.

 

[phideaux]

Keep in mind , it don't take a chimney fire to burn down your house.
Year after year of walls being exposed to heat can cause spontaneous combustion after so many years. The wood actually becomes a highly flammable fuel.

Jim

Oh, I have a friend that's a fire chief and chief investigator of fires.

 

[Caribou]

Okay, that explains it. The function of a chimney is to get the hot gasses out of the flue before they reach condensation temperatures. With your design you pull all the heat possible out of the fire but you cool the exhaust below the point where creosote is deposited. As long as you are willing to do the extra maintenance I can see why you like the radiation into the upper floors. I insulate metal flues like your's with vermiculite.

Your secondary air chamber isn't getting enough air or the fire is too low to ignite the gasses leaving unburned fuel. A hotter fire should help and possibly adjusting the secondary air, if that is possible.

You will need to keep the flue clean because as the flue diameter plugs up the reduction in diameter reduces the amount of air that is allowed into fire causing incomplete combustion which in turn cause creosote deposition at increasing rates. This may be your major problem.

This is getting a bit long for a post. I had my own heating business for a few years. If you have any questions and want to give me a call, PM me and I'll send you my phone number.

 

[Aerindel]

https://en.wikipedia.org/wiki/Teaching_grandmother_to_suck_eggs

 

[LadyLocust]

https://en.wikipedia.org/wiki/Teaching_grandmother_to_suck_eggs

We used to use a tire chain on a rope when we didn't have access to a brush. I'm sure you've got your methods, but it worked for us and the weight of the chain helped it go down the pipe.

 

[Aerindel]

I have a brush on 30' feet of chain, and a 4' steel nut on the the other end. When I have to clean I open my roof hatch, which I buily next to the chimney, and through the nut and the chain down the pipe. Then I go down to the ground floor and use the chain to pull the brush through the pipe all the way down into the stove.

 

[Peanut]

@Aerindel

I was researching another topic, how to clean impurities from salt but the strangest thing repeatedly came up in my searches...

Burning rock salt to clean tar from a chimney! Evidently the chlorine changes the chemical make up of creosote making it easy to get rid of.

https://homearise.com/burning-rock-salt-clean-chimney/
https://www.woodsmanreport.com/burning-rock-salt-to-clean-chimney/

Has anyone one heard of this? It seems to be a common chimney cleaning method in England.

 

[phideaux]

@Peanut , been doing it for years. At least 2 to 3 times a season , when I have a hot fire going.
I usually throw in a couple cups full.

Maybe that's why I never have anything show up when I do sweep the chimney every 3-4 years.
I use rock salt for making home made ice cream , or for ice on sidewalks.

Jim

 

[Meerkat]

Only used our fire place once ,it smoked up living room so need to fix outside vents'someday'. Don't need it really down here anyway.Its a pass thru serves bedroom and living room.

 

[Peanut]

@Peanut , been doing it for years. At least 2 to 3 times a season , when I have a hot fire going.
I usually throw in a couple cups full.

Maybe that's why I never have anything show up when I do sweep the chimney every 3-4 years.
I use rock salt for making home made ice cream , or for ice on sidewalks.

Jim

Evidently rock salt works really well at getting rid of creosote in chimneys. I read lots of comments on various forums and websites.

However, none of them adequately describe what is actually taking place. Most say it "dries out" the tar in the creosote, turning it into paper thin "ash". Most likely there is a chemical reaction of some type.

 

[Neb]

Evidently rock salt works really well at getting rid of creosote in chimneys. I read lots of comments on various forums and websites.

However, none of them adequately describe what is actually taking place. Most say it "dries out" the tar in the creosote, turning it into paper thin "ash". Most likely there is a chemical reaction of some type.

I question a chemical reaction because salt does not burn. It is an ionic bond. Melt, sublimate may be.

I can't answer.

Ben

 

[SheepDog]

The salt combines with water (remember even dry wood is about 30% water) to form an acidic mixture (typically combining the sulfur to make sulfuric acid) that works on the creosote to release it from the chimney and burn it. Table or rock salt works well but there are more colorful salts that do the same thing and add a bit of color to your fire. Copper sulfate is one such salt. It adds blue color to the fire.
There is a caution to these methods; If you have a steel liner or flu pipe don't use this method very often. The acid will corrode the pipe and you will have to replace it. On the other hand if you have a ceramic flu (brick or terracotta) then you are good to go. Copper sulfate is easier on the steel flues but excess use will still cause rust.