wall darkenning possibly due to the condensation in chimney

wall darkenning possibly due to the condensation in chimney

PostBy: jasius On: Mon Mar 27, 2017 9:20 pm

So thanks to the members of this forum I enjoyed first warm Winter in our new home.

Now it's time to ask another question. Last Summer I noticed darkening of the brick wall underneath where coal stove exhaust pipe goes into. It was bizarre and I suspected rain coming inside since that thing would become dark and visibly damp when it was raining outside. I put a cap on the chimney - did not work, still was dark and moist when raining outside.

I forgot over the Winter but today I tried making coal stove work again after few days of standstill. That was a nightmare since the room was much colder than the outside and it took me forever. But then I noticed during getting the stove working the moisture literally condensing on the walls inside the stove. So I think it's related. I think somehow moisture from warmer air outside gets drawn inside my chimney and condenses - by the way my pipe also is visibly corroded (not by the sulfur in coal since I haven't touched the stove in 2 years after I moved in since I did not know how to run it). So it must be moisture.

So my question is: what is it I am observing and how to deal with it. I am afraid it will damage my walls. I attached the pic

thanks all

Jonas
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dark wall under the pipe
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jasius
 
Hand Fed Coal Stove: Franco Belge model 144.08.02


Re: wall darkenning possibly due to the condensation in chimney

PostBy: franco b On: Mon Mar 27, 2017 9:27 pm

If the exposed chimney is brick, many common bricks will absorb water like a sponge. Cap makes no difference. Painting the brick with the right paint will stop it.
franco b
 
Hand Fed Coal Stove: V ermont Castings 2310, Franco Belge 262
Baseburners & Antiques: Glenwood Modern Oak 114
Coal Size/Type: nut and pea

Re: wall darkenning possibly due to the condensation in chimney

PostBy: blrman07 On: Tue Mar 28, 2017 7:17 am

Sounds like your chimney is drawing the outside air down into the stove. I had a wood burner in a basement that was always cold and I thought burning some wood down there would help. I had exactly the same problem. Horrible to get the stove lit until I discovered that if I opened the basement door (it had no windows which I hated) and put a propane torch in the firebox for 5 minutes first to warm up the air and get a draft going. Then I could light the wood without getting smoked out. If I got in a hurry and didn't pre warm that stove then the stove was not going to light and I was going to smoke us out.

Probably your house is tight and your not getting enough makeup air. Try opening a window during light off and put that torch in there to get a flow going up the chimney and I believe you'll have much less trouble.
blrman07
 
Hand Fed Coal Boiler: Bucket a Day
Hand Fed Coal Stove: Vigilant Casting 2310
Coal Size/Type: Pea/Nut/Wood in the VC and anything that will fit in the Bucket a Day. It's not fussy.

Re: wall darkenning possibly due to the condensation in chimney

PostBy: Lightning On: Tue Mar 28, 2017 2:35 pm

Do you have an IR temp gun? I wonder if you took temp readings of that area under the pipe (where the condensation is occurring) if that brick (for whatever reason) is colder than the bricks around it, where the condensation is not occurring.. It seems to me the bricks would need to be cold for condensation to form on them. Unless the moisture is coming directly thru the brick from outside. I think your first step to solving the problem is to see if possibly the bricks are just cold, causing condensation to form from moisture in the surrounding air. Where is the ground level directly on the other side of that area below the stove pipe? or is that an interior chimney?
Lightning
 
Hand Fed Coal Furnace: Overmodified/Bored out Clayton 1537
Coal Size/Type: Anthracite/Awesome Size

Re: wall darkenning possibly due to the condensation in chimney

PostBy: davidmcbeth3 On: Tue Mar 28, 2017 2:41 pm

blrman07 wrote:Sounds like your chimney is drawing the outside air down into the stove. I had a wood burner in a basement that was always cold and I thought burning some wood down there would help. I had exactly the same problem. Horrible to get the stove lit until I discovered that if I opened the basement door (it had no windows which I hated) and put a propane torch in the firebox for 5 minutes first to warm up the air and get a draft going. Then I could light the wood without getting smoked out. If I got in a hurry and didn't pre warm that stove then the stove was not going to light and I was going to smoke us out.

Probably your house is tight and your not getting enough makeup air. Try opening a window during light off and put that torch in there to get a flow going up the chimney and I believe you'll have much less trouble.


Maybe right .. I know my Hitzer sucks up mucho air. Its harder to close exterior doors when its running.
davidmcbeth3
 
Coal Size/Type: nut/pea/anthra
Stove/Furnace Make: Hitzer
Stove/Furnace Model: 503

Re: wall darkenning possibly due to the condensation in chimney

PostBy: Lightning On: Tue Mar 28, 2017 2:57 pm

davidmcbeth3 wrote: Its harder to close exterior doors when its running.

Na, that's probably house stack effect causing that. I've noticed that too. :)
Lightning
 
Hand Fed Coal Furnace: Overmodified/Bored out Clayton 1537
Coal Size/Type: Anthracite/Awesome Size

Re: wall darkenning possibly due to the condensation in chimney

PostBy: jasius On: Tue Mar 28, 2017 5:44 pm

Lightning wrote:Do you have an IR temp gun? I wonder if you took temp readings of that area under the pipe (where the condensation is occurring) if that brick (for whatever reason) is colder than the bricks around it, where the condensation is not occurring.. It seems to me the bricks would need to be cold for condensation to form on them. Unless the moisture is coming directly thru the brick from outside. I think your first step to solving the problem is to see if possibly the bricks are just cold, causing condensation to form from moisture in the surrounding air. Where is the ground level directly on the other side of that area below the stove pipe? or is that an interior chimney?


Thank you. I will try to measure it. This red brick wall is an inside wall. Chimney then goes out into the external brick chimney that is white brick. I think the ground level is a little bit lower on the other side for the white brick chimney than the black spot is situated. So really it's not the problem lighting it up, it is more a problem of structural integrity whether condensation is not ruining my wall. I will wait for the proper conditions - it's usually when raining outside and my room is colder than the outside - and measure the temperatures.

By the same token, can anybody recommend a simple inexpensive IR T-meter?
jasius
 
Hand Fed Coal Stove: Franco Belge model 144.08.02

Re: wall darkenning possibly due to the condensation in chimney

PostBy: michaelanthony On: Tue Mar 28, 2017 6:57 pm

michaelanthony
 
Hand Fed Coal Stove: Vigilant 2310, gold marc box stove, vogelzang pot belly coat rack
Baseburners & Antiques: Home Sparkle 12
Coal Size/Type: Coal Contractor's stove, a little Kimmels 'nut
Other Heating: Very cold FHA oil furnace