Water in chimney

[Xtrl9]

Im not sure if starting a new thread is the way to go or not but here we go.

I had some liquid running out of my recently replaced stove pipe (3 days ago, yes I used 3 screws at all joints). Brown liquid that smells of wood smoke. I'm pretty sure its just water not creosotr because I tried to test light some with a propane torch on the concrete floor and it just evaporated. Held it under the flame for over a minute.

I think this is a cracked flue liner, I have some square terracotta 7x11inside masonry which is pretty normal. I was having some water run down the face of the living room chimney a few months ago and had a roofer look at it. He told me to try covering the chimney to see if it helps (it didn't). The water in the basement floor has never happened before this week.

Thoughts?

 

[begreen]

Sounds like it needs to be inspected from the top down for the cap, crown and tiles condition. Might be mortar failing too.

 

[Xtrl9]

Its that "hand stone" masonry that looks like they took the biggest rocks from the creek and stuck them together. The visible mortar is fine to the eye it, damage/wear should be obvious yes? it has a cap on it, one of the four sided grate with a slanted box top things from a bigbox store. Or did I just describe the crown?

Top down inspection was done in the summer by me, I tried with a light in the bottom but it was blinding me. As far as I could see down with a light the tiles were alright.

Another wierd thing about this chimney other than it has 3 flues, one for the wood stove, one for the living room fireplace, and another one for a fireplace in the master bedroom; there's no cleanout at the bottom. I had to brush it and stick a shop vac hose down inside the basement flue for the wood stove to suck up the droppings.

 

[coaly]

Is this with a stove connected and in operation? Is this a 6 inch outlet stove increased to the 7 X 11 inside flue dimension? That's a recipe for condensation from flue gasses with even dry wood.

 

[bholler]

The visible mortar is fine to the eye it, damage/wear should be obvious yes?

no not nessecarily

 

[Xtrl9]

Is this with a stove connected and in operation? Is this a 6 inch outlet stove increased to the 7 X 11 inside flue dimension? That's a recipe for condensation from flue gasses with even dry wood.

Approximate dimensions but yeah to the rest of that. The each burner has it's own flue which makes no sense to me with the size of the one on the wood stove.

Bholler, did I describe the crown cap situation well enough? The top "mortar" has a look of some yelloish epoxy on it. How do I check the integrity of mortar? Hit it or try to wiggle stones?

 

[coaly]

The stove flue needs a 6 inch insulated liner. It should be the same size as stove outlet all the way up.
You can't allow a 6 inch diameter pipe which is 28.26 square inches to increase to 77 square inches. Gasses cool when they expand, below 250* f water vapor from combustion condenses and it drips back into the stove.

I'll clip and paste the explanation of how much water comes from dry wood from this thread with similar issue;
https://www.hearth.com/talk/threads/reversed-flue-collar-creosote-leak.150046/#post-2013948

Info condensed from Woodburners Encyclopedia;
Water vapor is a by product of combustion when hydrogen is present. Oven dry wood contains 6% hydrogen. One pound oven dry wood produces .54 pounds of water vapor. wood with moisture content of 25% contains another 1/4 pound of water vapor. When entire vent system is above condensing point of 250* flue gasses rarely condense.
The formula for calculating water vapor formed burning any fuel is 9 being the ratio of the molecular weight of water to hydrogen. Every pound of hydrogen becomes 9 pounds of water. So a fuel containing approx. 6% hydrogen such as dry wood produces .54 pounds water for every pound burned.

 

[Xtrl9]

Some science that confirms what im seeing!!
I asked begreen about the l slight smoke I have been seeing in another thread. Its behavior sounds like the steam you described.

I'm not opposed to putting a liner in but at this point since I found out my install is illegal from my first thread I'm going to look at putting an insert in my living room since it would heat more efficiently the living space. Its right below the open air stair case to the master bedroom. That's if I can get someone to find out what the water running out of my chimney is from.

So chasing burn times is probably not what I should do in the mean time. I grew up running my dad's insert, but I sure wouldn't mind advice on how to keep my house from catching on fire.

I ordered a thermometer for the stove pipe never done anything but drip water and see if it sizzles. Short hot fires and no smoldering will be ok to get me through the winter?

 

[bholler]

Bholler, did I describe the crown cap situation well enough? The top "mortar" has a look of some yelloish epoxy on it. How do I check the integrity of mortar? Hit it or try to wiggle stones?

It would probaly just be small cracks in the mortar. But i agree with coaly it is very likely condensation.

 

[coaly]

Water only drips from the flue you're using right?

Steam will look like white smoke at the chimney top and dissipate as it drifts away.

If you have a flue damper, keep it wide open. The chimney needs all the heat it can get.

Just like a car exhaust when it's cold, you can see how much hydrogen in the fuel you are burning. A hot exhaust will not show the vapor at the end since it is above condensing point, but it's still there. The water will drip out of the tail pipe when cold showing how much water vapor is created at idle using very little fuel. The chimney is the same way. It needs to be above 250* all the way to the top. That isn't difficult with a flue the same size as stove outlet all the way up. Insulation around the flue liner makes it even easier. To give you an idea how much flue gasses cool when allowed to expand, I used an infra red thermometer recently on a neighbors connector pipe that increases from 6 to 8 before his 8 inch masonry chimney. These are surface temps, so flue gas can be 50% or more higher depending on velocity. 425* 1 foot above stove on 6 inch pipe. 350* at elbow 2 feet from stove. Short pipe a couple inches, then increaser from 6 to 8. 300* 6 inch side of increaser, 170* at 8 inch side of increaser. That temperature drop is from 28.26 square inch pipe to 50.24 square inch pipe. You're tripling the square inch size of your area. You don't have enough heat loss in a small stove to get enough heat into your chimney to keep it above 250* all the way up.
Smoke particles stick to flue walls when moist causing rapid creosote build up. Lots of air burning fast creates less smoke particles and a hotter flue. I wouldn't say short fires letting the flue cool constantly is better. Like a cars exhaust, long trips keeping it hot keep it dry. Short trips constantly letting it cool keeps it wet and rots away much faster. It may take a long time to heat your flue to the top, if ever. A larger stove with 8 inch outlet allows much more heat up, and wastes more fuel, but it will stay cleaner and help eliminate the condensing.
If you leave enough heat out of your stove to heat the chimney properly, you won't have much left to heat the house. (the taller the chimney the worse in your case, since it adds to the cubic inch area you're trying to keep above 250*) Common problem with small stove / large chimney. People don't realize the fire has to heat the chimney first to make the stove work. A bigger chimney doesn't mean more draft, it is capable of more draft when given more heat.
If your chimney is exposed outside, it will condense much more when colder.

For your insert;
A fireplace looses most of its heat up the larger flue since it has to be large to evacuate all the smoke. (along with heat) When you contain the fire in a box with controlled air intake and smaller outlet, the heat radiates into the house. Now you don't have enough heat for the larger chimney. So it needs a liner the size of Insert outlet. Normally a insulation type mortar mix is poured around the liner to help keep it hot inside.

 

[Xtrl9]

The water drips...when yes. This is my second winter. It has never or at least was not noticed by me dripped out of the stove pipe until 4 days ago now. And it has been below freezing so I have had a fire most of the week. There is/was another place on the chimney that water runs out of when it rains or I suppose when this 2 feet of snow melts it will.


I 100% did not know the chimney was supposed to be hot before you explained it. I did vaguely know if you have stove pipe the temp was important and also knew internal temps were higher than outside surface. I did try to find a probe thermometer but most of what I found was for double wall.

I do have an inline damper and will leave in the wide open position.

Here's my other thread where I asked about the damper and show most of the basement setup. I will be getting on the roof asap to take photos up there. Anything specific that will help you guys help me?
https://www.hearth.com/talk/threads/mountaineer-but-not-a-vogelzang.152025/#post-2041199

 

[coaly]

Yes, a stove won't work properly without a hot chimney. The hot rising gasses inside flue being lighter than outside air is what causes a low pressure area in connector pipe and stove. This is draft, measured at the strongest area which is at the flue collar on stove. The lower pressure area in stove allows atmospheric air pressure to push air into the stove. Less draft is less air into stove which lowers output. So the chimney is the engine that drives the stove. When low pressure areas move over, you don't have as much air pressure pushing in, so the stove will act sluggish and need a larger air intake opening for the lower air pressure to push into. If you had the right size chimney, damper setting is used to control draft and is adjusted for weather conditions. (pressure and temperature) The colder outside, the larger the temperature differential in and out of the flue, so the stronger the draft. The damper controls the velocity of flow up the chimney which affects flue temperature which affects the stove. Like a throttle on the chimney, which affects the stove.
Since it's not easy to measure temperature near the top, it's a guess as to how much heat a chimney requires to stay clean and give the stove the required draft. If you had an insulated flue the size of stove outlet it would loose relatively little to the top. 350* or as little as 300* where it dumps into chimney may stay hot enough to the top in a short insulated flue. The taller the flue, the stronger the draft but the more heat required all the way up. Checking creosote formation near the top frequently tells you if you're running hot enough. In your case the expanding gasses cool so much in the flue 3 times the size, you need to know flue temperature more than pipe temp. When you're close to the proper draft and temperature, condensing of water vapor is eliminated as it rises out of the flue in vapor form.