Cat Stove and Smoking Galvanized Stove Pipe (Double Wall)

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.

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.

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: 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.

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.