Block Chimney Producing Water...

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mustangwagz

mustangwagz

Feeling the Heat
Oct 5, 2014
259
Western PA
Yah...the title says it all folks. THis post is on behalf of a gentleman at work and the problems him and his son are having.

Recently, My friend Chuck helped his son build a new block chimney. Its a teracota lined chimney like a lot of them are. He has his "woodchuck" wood burner plumbed into it. ANYTIME he runs the woodburner, irregardless of how hot he burns it, the chimney produces a TON of water. I was baffled, i asked "well...what exactly do you mean!?" he said that when its burning, There's a TON of water condensation or sweat coming down the inside of the chimney. Enough to fill the bottom of the chimney UP TO the cleanout door. Which is 8" or so above the ground. This is a 8x8 square chimney too btw folks. So...he's producing enough water to fill up and area thats atleast 8x8x8. He actually takes a small bucket and scoops out the water that collects in the bottom of the chimney via the cleanout door.

Has anyone ever heard of this? Can anyone gimme suggestions for chuck and his boy? I tried googling some stuff and came up with nothing, so i figured id ask yinz here. The only thing i can figure is that its its the block sweating?

If yinz all need more info, ill gladly ask chuck and his son anything ya need me to. hopefully we can make sense of whats going on for these gentlemen. Hell, its a new chimney! lol

THanks in advance folks!
 
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Could be the heat driving out moisture from the blocks and mortar but that should subside soon then. I would rather guess he burns wet wood and the moisture condenses on the cold chimney walls. Seasoned wood and an insulated liner would fix that.
 
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I saw that happen on a chimney that had recently been swept. Problem was it was so plugged up the sweep thought the brush was hitting the bottom. It wasn't. Smoke was sitting in the chimney and condensing.
I'm not sure why a new chimney would be plugged like that but these are the same symptoms.
 
Chimney is Clean as a whistle, barely used actually. And wood has been seasoned and dry for more than a year. He is kinda scared to use it and is super confused. No one seems to know why itds doing this.
 
Tenn Dave said:
Is it possible water is coming up from the ground?
Click to expand...
i suppose anything is possible, but its a cement bottom in the chimney and Chuck said he can watch the water run down the walls of it when he opens the clean out door. Said they go out every couple days and bail out the water..lol i was like WTF?!? Hence why i posted here, hoping someone can shed some light.

maybe something to do with water column or something!? who knows!
 
When I had my Pine Barren stove in my basement I had this exact same problem. I use to have to put a sump pump in through the cleanout door in the base of the chimney. Once a week I'd pump 2 five gallon buckets full of jet black water out of there. Never did figure out what was going on. It was a 8" terra cotta lined chimney over 25' high. Best I could figure out, it was condensation.
 
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mustangwagz said:
i suppose anything is possible, but its a cement bottom in the chimney and Chuck said he can watch the water run down the walls of it when he opens the clean out door. Said they go out every couple days and bail out the water..lol i was like WTF?!? Hence why i posted here, hoping someone can shed some light.

maybe something to do with water column or something!? who knows!
Click to expand...
I was thinking maybe ground water was saturating the cement base of the chimney and then turning into condensation when the warm air from the stove heated up the chimney flu. just a thought.
 
There is no water pipe going by the chimney by any chance?
 
nope no water pipes near it he said. I'm thinking its condensation but not sure why so much all at once. pretty wild.
 
Does it happen only when he got fire going? Does it happen when it rains? Or at all times?
 
I had the exact same thing when I first installed my wood furnace. Every day I would remove over a gallon of water before it would come out of the cleanout. Ours was condensation, which it sounds like his is also. After installing an insulated liner, the problem disappeared.
 
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mustangwagz said:
nope no water pipes near it he said. I'm thinking its condensation but not sure why so much all at once. pretty wild.
Click to expand...

Don't forget that at more than 40% moisture content of green wood almost half of the wood weight is water. Burn 10 pounds green wood in the furnace and get ~4 lb (approx. 1/2 gl) of water. That does not even include the water generated through the combustion process itself which produces CO2 and water.

Many people don't realize how much energy they are actually wasting by burning green wood.
 
ONly happens when he's burning his wood burner.

As for green wood, its been dry now for over a year as i stated earlier. He's got it under roof and in MY opinion, perfectly fine. Infact i brought a few pieces home to try in my stove just outta curiosity, and had absolutely no issues. Burns like typcial WELL seasoned, dry wood. lol So far im thinking most of you are on same thought process as i am by figuring its just condensation. Just odd as hell that its producing that much sweat! ill suggest the liner again. i suggested that once already cuz i myself dont prefer to use terracota pipe.
 
Even at dry wood levels H2O is one of the by-products of combustion. At 20% nominal moisture level that is still a quart of water per 10 lbs. We burn that much in one mild weather fire. An insulated liner would improve this situation by dramatically reducing condensation.
 
It is possible that in addition to the condensation that is happening, he needs to seal the outside brick work. The new bricks and mortar are acting like a sponge and soaking up moisture - particularly when it rains- not an unusual problem for a new chimney. There are products for this purpose - not Thompsons water seal though as that has little staying power. Soloxthane ( not sure of spelling) is what I used some 25 years ago.
 
burning wet wood. The water from the wood is condensing on the cool chimney. If he lines the chimney with an insulated liner it should resolve the issue. If he continues to burn wet wood in the chimney the problem will continue. Please note: Water is a natural by product of any combustion process. That is why you sometimes see water dripping from car mufflers in the winter. The wet wood is exacerbating the situation
 
Thanks guys, ill relay the info to chuck!
 
Mustangwagz did you ever find the answer to this issue? I have a similar situation with an older Fisher wood stove in the basement. I do not use it unless it gets real cold. If I let it set a few weeks between fires it pours the water when a fire is started. Water comes out of the cleanout for about 10-12 hours after it is first lit, then no problem. I have been trying to figure a way to collect the water in a bucket or something so it doesn't pour out onto the basement floor. Not easy to do with an 8" square flue and a round bucket! It also worries me that I will somehow damage the flue pipe.....
 
No, to this day it still does it... not sure why but still the same issue. He put a drain at the bottom of it and leaves it open.. lol LIke you said, its hard to work with.. not sure what would cause it.. I dunno much about "water column" or how ya measure it etc etc, but that may be the issue.. we kinda gave up on it because everyone seems to be stumped.
 
Why it builds up so much condensation is a mystery to me. In my case, it doesn't matter if it has rained since the last fire or not. Over a period of time without the heat of a fire, condensation builds up and the next fire brings down the flood. I guess I will have to keep a fire burning all winter to keep it dry: Must be one of those super duper scientific things, lol.
 
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Yah, science.. thats what im going with too.. lol Yah keep the fire warm and the wood seasoned and you'll be good! lol
 
Never saw this thread at the time but looking at the Woodchucks, depending on which model he has they either call for a 6" or 8" liner. They allow for larger cross sectional area but if he has the one calling for 6" (cross sectional area 28") and it's going into an 8x8" he's exceeding the area by more than 2X. Even the units using 8" round will be dumping into an over sized flue. Does he have a problem w/ creosote?
 
jatoxico said:
Never saw this thread at the time but looking at the Woodchucks, depending on which model he has they either call for a 6" or 8" liner. They allow for larger cross sectional area but if he has the one calling for 6" (cross sectional area 28") and it's going into an 8x8" he's exceeding the area by more than 2X. Even the units using 8" round will be dumping into an over sized flue. Does he have a problem w/ creosote?
Click to expand...
Might not, sounds like it's getting washed down regularly . I'm sure it's smoke condensing due to chimney size rather
than water coming through the block.
 
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