Cat Stove and Smoking Galvanized Stove Pipe (Double Wall)

[777funk]

EDIT: Selkirk DSP (double wall painted pipe which I believe is galv under the paint).

I've got quite a problem with our cat stove. We're getting fumes from overtemp galvanized fairly regularly. Here's the predicament. Please let me know if (or should I say where) I'm doing something wrong. Here's how I run the stove.

Assume good 2-3 inch bed of HOT glowing coals and I'll be recharging the stove.

Plan A (no problems with the stove pipe but lots of smoke from the stack):
1. Open Cat bypass
2. Gather wood load (1 year + dry split oak and hickory) to be inserted into stove
3. Open stove door
4. Insert the wood half way or to the top depending on how much heat will be needed
5. Close the door
6. Close the bypass

Here's what happens after 5 minutes... LOTS of billowing white smoke from the stack for about 1-2 hours until the wood is black and partially covered by embers. The cat closes lets smoke build up in the fire box and restricts airflow enough that the load takes a while to burn. Then once burning well it tapers off after a few hours to no smoke and only coals after about 5 hours.

Plan B (and here is where the galvanized fume problem occurs):
Same as above except step 6 is modified:
6. LEAVE THE BYPASS OPEN for 30 minutes until the new load is burning well.

BIG problem... now the stove pipe crackles and gets so hot that if I touch the outside (of the double wall pipe) with a wetted finger it basically bounces the water off in a boil. If I don't close the bypass when this is happening it will get so strong with galvanized and paint fumes that we have to open the windows.

I know what this is... CREOSOTE burning in the pipe creating a small chimney fire. But how do I stop this? Plan A seems to generate the creosote, but Plan B also is a problem since it'll fire the stack so hot that it creates fumes.

 

[NinjaTech]

Your saying galvanized. Like zinc coated silvery galvanized pipe?

Are you getting white steam that quickly dissipates a few feet from the end of the pipe, or is it legit smoke that lingers off in to the distance? Water vapor is normal, especially after a reload. Do you have a cat thermometer? If so, and your going with Plan A, is the cat staying active?

 

[777funk]

Sorry!! I'll update that, it's Selkirk double wall painted stove pipe but I believe it's galvanized underneath the black paint.

https://www.menards.com/main/heatin...0C11C565C61517110.tndm-prodapp1-external-mcom

And the temp is all the way up (as high as the thermometer ever reaches) when I close the cat bypass. It's definitely smoke and a cloud is a good way to describe it. It covers about 60x60 feet.

 

[bholler]

What stove is this do you have a probe for the cat? what type of pipe are you talking about?

 

[NinjaTech]

You didn't mention what your doing with the air controls when doing your reloads? Are you touching those at all? You only mentioned how your managing the bypass.

 

[bholler]

Sorry!! I'll update that, it's Selkirk double wall painted stove pipe but I believe it's galvanized underneath the black paint.

No it is not galvanized. And you should not be pegging the thermometer that is why it is to hot.

 

[kennyp2339]

Plan A is the best way to run that stove from a hot reload, I'm thinking the main problem is wet wood. Classic white smoke coming from the chimney for 2 hours is a clear indicator that the wood being used is not quite ready to be burned.
Plan B is tough on the stove (excessive temps going strait up the flue) again wet wood will burn but it needs a ton of air (damper open increases draft due to lack of bends the smoke has to go in the stove) the heat created goes up the flue and that why the smoke pipe gets really hot.
The answer is find a dryer supply to experiment with and try to stay with plan A if you can.

 

[777funk]

What I've got has air dried for a year. It's only roughly covered (still sees some rain) but it doesn't feel wet on the outside when I burn it. I store it out of the rain for the last week or two before use.

As far as the damper, I have the air inlets wide open when I burn.

bholler: I get smoke no matter where the probe is at including as hot as it gets with full air and a full load of wood. As far as the coating... I'm not sure it's galvanized. But whatever it is, it sure stinks up the house. And it sure smells like galvanized the few times I've welded conduit etc for quick projects (very well ventilated).

Lastly, I'm sure the cat is old (probably original). Maybe it just doesn't work anymore. But then again, the amount of smoke I'm getting... seems like something else is wrong.

 

[bholler]

Lastly, I'm sure the cat is old (probably original). Maybe it just doesn't work anymore. But then again, the amount of smoke I'm getting... seems like something else is wrong.

Well it sounds to me like you have wood that is not dry enough a cat that is long past it's useful life And you are running with the air wide open which is seriously overfiring the stove which leads to the smell

 

[Nick Mystic]

I agree that your wood is probably too wet if it is oak and only seasoned for a year. As for your reload routine: After you reload on a bed of coals as hot as you indicated I would shut the door and leave the bypass open, but not for a half hour, just long enough for the wood to get fairly well engaged with flames. Once that happens I would shut the bypass and let your cat take over. In my Woodstock Classic I can lift the top of the stove and visually look at the cat to see if it is glowing so I know it's working. A reload on hot coals (2 to 3 inches thick as you indicated) will generally ignite well seasoned splits within a few minutes. You are probably loosing a lot of heat up your flue if you are leaving your bypass open for 30 minutes with each hot reload.

 

[777funk]

bholler: I'm sure you're right on the cat and probably on the wood. As far as the air being wide open during the main burn, that's not leading to the smell I'm describing. The overheated stove pipe doesn't happen when crusing and the cat is in use (only when bypassed and flames are hitting it direct). That's where the problem is coming in.

Interesting Nick. I'll have to see what the same wood does next year (will be 2 years). Also, I usually don't leave the cat bypassed for 30 minutes. I do more along the lines of what you say or don't bypass it at all. I tried opening it for the longer period to see if I could avoid the smoke cloud after a fresh reload. It actually worked because the flue gets so hot it burns the smoke. Obviously in-efficient, causes the overtemp paint fumes, not advantageous in several ways. I'll have to see what I get next year with 2 years on the oak and shagbark hickory.

I'll also have to try replacing the cat. I guess I haven't replaced it yet because the house heats fine. I burned 3.5 cords approx last year to heat 1200 sq ft with average 20F temps outdoors most of the Fall, Winter, Spring with a few dips into the teens in January and February. I'll probably burn a similar quantity of wood this year. Cats are pretty expensive. But I don't like the smoke either. I'll try the longer seasoned wood first since that doesn't cost anything.

 

[bholler]

bholler: I'm sure you're right on the cat and probably on the wood. As far as the air being wide open during the main burn, that's not leading to the smell I'm describing. The overheated stove pipe doesn't happen when crusing and the cat is in use (only when bypassed and flames are hitting it direct). That's where the problem is coming in.

But running with the air wide open is still overfiring the stove whether it makes the smell or not. If leaving the bypass open makes it smell don't leave it open so long. What are your cat temps and your stove pipe temps? Burning dry wood may help a little but it is not going to fix a 25 year old cat. Have you ever cleaned the cat? What condition is it in?

 

[777funk]

It must have been just a bad load of wet wood. A dead oak was cut this year and a few pieces got mixed in. I burned mostly old hickory today and there's a LOT less smoke. Still a small amount when new logs are loaded but not bad. No clouds with this load.

I did clean the cat and it's past it's prime (cracks etc). Surprisingly we still get a lot of heat from the stove without burning a ton of wood. I'd guess we use 10 pieces of 8" splits per day when it's 10-20F out.

 

[webby3650]

bholler: I'm sure you're right on the cat and probably on the wood. As far as the air being wide open during the main burn, that's not leading to the smell I'm describing. The overheated stove pipe doesn't happen when crusing and the cat is in use (only when bypassed and flames are hitting it direct). That's where the problem is coming in.

Interesting Nick. I'll have to see what the same wood does next year (will be 2 years). Also, I usually don't leave the cat bypassed for 30 minutes. I do more along the lines of what you say or don't bypass it at all. I tried opening it for the longer period to see if I could avoid the smoke cloud after a fresh reload. It actually worked because the flue gets so hot it burns the smoke. Obviously in-efficient, causes the overtemp paint fumes, not advantageous in several ways. I'll have to see what I get next year with 2 years on the oak and shagbark hickory.

I'll also have to try replacing the cat. I guess I haven't replaced it yet because the house heats fine. I burned 3.5 cords approx last year to heat 1200 sq ft with average 20F temps outdoors most of the Fall, Winter, Spring with a few dips into the teens in January and February. I'll probably burn a similar quantity of wood this year. Cats are pretty expensive. But I don't like the smoke either. I'll try the longer seasoned wood first since that doesn't cost anything.

As a reference, I burn 3.5 cords max and heat 2200 square feet exclusively with wood. 3.5 would be the most I've ever used by the way, I was running 2 stoves when this happened.

What stove are you using?