Fireplace damper and icing ?

[Sono]

Last week I opened the dampers in my fireplace ( large one in the bottom and a chain operated one up top of the chimney ) and started a small fire to check draft and everything worked fine, kept a small fire going for a few hours before letting it brn out for the night and closing the dampers . Temps have been -5 this past weekend and since, so I went to lite another fire and the top damper would not open, shaking the chain, yanking ect.... nothing would budge it? So today it hit 35 and I got on the roof, pulled the cap and operated the damper by hand which was fairly easy but a little sticky due to icing inside the chimney under the damper and on the clay liners ??? What is causing the icing inside the chimney as Ive never heard or seen of this happening before? very odd but id like to figure out how to fix this so it works correctly.

 

[begreen]

Extreme cold weather often brings about new problems. Warmer room air full of moisture crept by the lower damper and froze on the sides of the flue. The mass of the brick had stored enough cold that just getting a little above freezing was not enough for the flue to thaw out.

 

[Sono]

Extreme cold weather often brings about new problems. Warmer room air full of moisture crept by the lower damper and froze on the sides of the flue. The mass of the brick had stored enough cold that just getting a little above freezing was not enough for the flue to thaw out.

Understandable but wouldnt this be some sort of design flaw, a hazard by the makers if it lacks some sort of fail safe to operate regardles of temps ? The humidity inside the house is extremely low 30% and the fireplace has glass doors as well so it just baffles me. I got off the roof and came inside and already the damper wont open at top so Im kinda irked as I wanted to light a fire.....

 

[Sono]

I am actually debating knocking the chimney down this spring/summer, patch the roof up, tear out the entire fireplace and install a wood stove. Hate this fireplace anyways taking up so much room ( it basically seperates the livingroom from the kitchen in the middle of the house.

 

[Sono]

seems the sun warmed it up enough for the damper to operate now so I got back up to check it and was wide open and moved freely... lit another small fire to check operation , being this old house was recently weatherproofed and pretty much air tight I dont think Im getting enough draft as the fire seems to die down ( wood is well seasoned and covered 2 years now Oak and Cherry? Not sure about fireplaces as this is the first Ive owned, didnt have this issue with my parents 1800s home lighting fires in a fireplace? All dampers are wide open ( roof, inside firebox and below the glass doors. Smoking good outside but when I open the doors the smoke rolls in. shouldnt be doing that.

 

[EatenByLimestone]

Warm air has the ability to hold more moisture than cold air. Even though the humidity is only 30%, it still may be higher than the cold air may be able to hold. As the warm air cools down. The moisture condenses on the surfaces around it, then freezes.

We see this in reverse as cold air is sucked into the house and becomes warm, dry air, this causes our wood floors to open gaps, etc.

 

[30WCF]

What is causing the icing inside the chimney as Ive never heard or seen of this happening before?

Not having a hot smoke keeping the chimney warm. I kid. 🥸

 

[Sono]

Not having a hot smoke keeping the chimney warm. I kid. 🥸

It was plenty hot then shut down for the night.... its the first time Ive ever experienced a damper not operating properly when needed? Im almost thinking to pull that top damper out and throw it away.

 

[EatenByLimestone]

Maybe I’m biased coming from a pest and wildlife background, but that damper could keep a lot of animals out of the chimney. It could be saving you thousands of dollars, lol. One raccoon setting up shop down there can cause much more drama than you’d expect! We once had one open the lower damper and wander around the house a bit!

 

[begreen]

Maybe I’m biased coming from a pest and wildlife background, but that damper could keep a lot of animals out of the chimney. It could be saving you thousands of dollars, lol. One raccoon setting up shop down there can cause much more drama than you’d expect! We once had one open the lower damper and wander around the house a bit!

A coarse screen under the cap would solve that.

 

[Sono]

Maybe I’m biased coming from a pest and wildlife background, but that damper could keep a lot of animals out of the chimney. It could be saving you thousands of dollars, lol. One raccoon setting up shop down there can cause much more drama than you’d expect! We once had one open the lower damper and wander around the house a bit!

Oh I know all about that as this house was run down , the soffits were torn down and raccoons made home in the attic tearing apart all the flex duct, all the insulation..ect... I got it all sealed up after they evacuated in the spring. But as far as the chimney it has a screened cap and sealed, the damper is inside the chimney itself and can just lift out ( it sits on the clay liners inside ) so I dont think there would be an issue with anything getting inside the chimney if the damper was removed. Ive been researching and see other chimney caps that are dampers themselves where the cap actually pulls down and seals the chimney from the outside instead of inside BUT I wonder if theres heavy snow or ice if the cap will pop back up when needed? It just seemed the internal style damper is protected from the elements but mine is proving otherwise.... Mine is simular to the cast iron picture ( mine is stainless steel inside a stainless box ) the other picture are the pop up caps.

 

[bholler]

Oh I know all about that as this house was run down , the soffits were torn down and raccoons made home in the attic tearing apart all the flex duct, all the insulation..ect... I got it all sealed up after they evacuated in the spring. But as far as the chimney it has a screened cap and sealed, the damper is inside the chimney itself and can just lift out ( it sits on the clay liners inside ) so I dont think there would be an issue with anything getting inside the chimney if the damper was removed. Ive been researching and see other chimney caps that are dampers themselves where the cap actually pulls down and seals the chimney from the outside instead of inside BUT I wonder if theres heavy snow or ice if the cap will pop back up when needed? It just seemed the internal style damper is protected from the elements but mine is proving otherwise.... Mine is simular to the cast iron picture ( mine is stainless steel inside a stainless box ) the other picture are the pop up caps.

View attachment 323171 View attachment 323175

Is the damper adjusted properly and are the seals in good condition? Usually if the damper is sealing properly it keeps icing problems to a minimum.

 

[bigealta]

i'd leave the masonry as thermal mass and put a woodstove or insert in that fireplace with a new 6" chimney pipe. Should solve multiple problems.

 

[begreen]

Oh I know all about that as this house was run down , the soffits were torn down and raccoons made home in the attic tearing apart all the flex duct, all the insulation..ect... I got it all sealed up after they evacuated in the spring. But as far as the chimney it has a screened cap and sealed, the damper is inside the chimney itself and can just lift out ( it sits on the clay liners inside ) so I dont think there would be an issue with anything getting inside the chimney if the damper was removed. Ive been researching and see other chimney caps that are dampers themselves where the cap actually pulls down and seals the chimney from the outside instead of inside BUT I wonder if theres heavy snow or ice if the cap will pop back up when needed? It just seemed the internal style damper is protected from the elements but mine is proving otherwise.... Mine is simular to the cast iron picture ( mine is stainless steel inside a stainless box ) the other picture are the pop up caps.

View attachment 323171 View attachment 323175

The two flues terminating at the same height present an additional, unrelated problem of smoke siphoning. Is that why the other one is capped?

 

[Sono]

Is the damper adjusted properly and are the seals in good condition? Usually if the damper is sealing properly it keeps icing problems to a minimum.

No seals , its a stainless box with a stainless flap inside, where the pivot point is offset. So when the weight is released on the chain it drops down to open and when the weight is attached to the chain it flips back up and seals so the flap is actually longer than the length of the box so it seals at an angle as well as add weight so the flap falls when chain weight is released. the flap is just a tad smaller than the width of the box so it will pivot unless soot/cresote or ice blocks it. I dont think it would really hurt to remove the upper damper BUT the lower damper does not seal completely due to the chain hanging through for the top damper ( but wouldnt be an issue once top damper is removed since the chain will also be removed.

 

[Sono]

A coarse screen under the cap would solve that.

View attachment 323161

thats is what is on there now

 

[stoveliker]

If you keep the fireplace, I wonder if one of those balloon type seals would work well (seal it from the bottom - after the top one is gone).

 

[Sono]

If you keep the fireplace, I wonder if one of those balloon type seals would work well (seal it from the bottom - after the top one is gone).

Im debating just tearing the fireplace out this year and install a wood stove with pipes... easier and less complicated... also a lot more efficient heating.

 

[stoveliker]

I completely agree with that.