Chimney cap darkening

[LAndrim]

Hello All,

Newbie with a new wood stove install: a Lennox canyon ST310. Two weeks old and VERY happy with the heat output.
1. I get the fire going fairly well using very seasoned mixed hardwood, starting small and hot fire.
2. Then, using a thermometer probe 18" up the stack, I keep the temp between 400 and 500 once I get an initial hot fire.
3. So, I think I'm within the guidelines that I've been reading about in the forums.
Here's my concern:

The stove pipe goes up thru my roof (not in fireplace), and the round chimney cap is already darkening with a browninsh color.
Any ideas why? Is this normal?

Thanks in advance for your help!

 

[Hanko]

If you stop burning wood, all the brown will dissapear.

 

[BrotherBart]

Perfectly normal.

 

[pen]

The chimney cap darkening is normal, however, running your stove at 400-500 on your probe 18 inches up to me is too cool but of course I don't know when in the burn cycle you are seeing these temps. In my opinion, a probe 18 inches up single wall pipe should read no less than 800 before turning down the air any.

Here is a bunch of reading for you to do so that you can make your own mind up on the subject.

https://www.hearth.com/econtent/index.php/forums/viewthread/63964/

https://www.hearth.com/econtent/index.php/forums/viewthread/63488/

https://www.hearth.com/econtent/index.php/forums/viewthread/62731/

https://www.hearth.com/econtent/index.php/forums/viewthread/62136/

https://www.hearth.com/econtent/index.php/forums/viewthread/51149/

https://www.hearth.com/econtent/index.php/forums/viewthread/61907/

pen

 

[LAndrim]

Thanks moderator! Was afraid i was burning too hot!

 

[Cate68]

You should be fine, mine is the same.

 

[LAndrim]

Thanks Pyro,

Just to clarify, it's a double pipe and I'm using a Condair probe( I've read they are not 100% reliable). Thanks for your insights! I'll check out your links, much appreciated!

 

[trailrated]

The chimney cap darkening is normal, however, running your stove at 400-500 on your probe 18 inches up to me is too cool but of course I don't know when in the burn cycle you are seeing these temps. In my opinion, a probe 18 inches up single wall pipe should read no less than 800 before turning down the air any.

Here is a bunch of reading for you to do so that you can make your own mind up on the subject.

https://www.hearth.com/econtent/index.php/forums/viewthread/63964/

https://www.hearth.com/econtent/index.php/forums/viewthread/63488/

https://www.hearth.com/econtent/index.php/forums/viewthread/62731/

https://www.hearth.com/econtent/index.php/forums/viewthread/62136/

https://www.hearth.com/econtent/index.php/forums/viewthread/51149/

https://www.hearth.com/econtent/index.php/forums/viewthread/61907/

pen

800*!! Are you serious? My single wall pipe has never reached that high and if it did it would be cherry red. I've already lost paint about 12inches up from the stove from being to hot I suppose.

 

[pen]

It would start to glow in the dark at 950 and that would have to be a surface temp. Internal temps would read much higher.


pen

 

[LAndrim]

Hey guys...it's a double pipe, not single. Thanks!

 

[pen]

since you have double wall you have a better chance at getting an accurate reading w/ the probe. These probes are very reliable, just maybe not so accurate depending on the setup. However, accuracy is not exactly what is necessary, consistency is what is required and these are. You just need to learn your setup.

I had to move mine up higher on the pipe to get a believable reading w/ single wall. Keep it under 1k for most burning and you'll have no problems. If you are only reading 400-500 on a probe thermometer, you are WAY too cool. Burn hotter.

pen

 

[LAndrim]

Thanks for the suggestion of burning hotter. With my probe at 18" above stove, and knowing it's double wall pipe, you're suggesting under 1K ( 1000 F)?

just want to make sure about the number. Thanks again!

 

[Adios Pantalones]

If it's burning well with no smoke out the chimney- you are golden. As said above- darkening is normal.

 

[pen]

Thanks for the suggestion of burning hotter. With my probe at 18" above stove, and knowing it's double wall pipe, you're suggesting under 1K ( 1000 F)?

just want to make sure about the number. Thanks again!

yep. Some people recommend a "daily hot burn" I don't. I recommend burning hot all the time and burning the stove in cycles rather than throwing a piece of 2 of wood in every few hours.

My concern w/ burning hot only once in a while is that during the time the operator is burning too cool, creosote builds up and then could ignite during a hot fire. Keeping a fire burning good and hot all the time helps keep creosote from building up close to the stove.

pen