Does the size of the split affect the catalytic combustion?

Huh, a cat gets most of its heat from the gases it combusts, not from the heat of the primary fire.

A cleaner burning fire results in less combustion in the cat (because the primary fire is already doing that when burning cleanly), and thus lower cat temps.

Indeed see that in my stove.

 

That is fine.
Mine glows often (because I run the stove often low enough to have a dirty primary fire, or just glowing stuff, no flame, leading to a lot of gases and smoke for the cat to burn, and thus to higher cat temps).

 

Houston we have liftoff. Totally normal.

 

So is a “cat” stove just a fancy “smokeless firepit “?

 

The same as a tube stove.
Some design to combust what the primary fire has not combusted yet.
Different solution to get that done.

Tube stove is in fact similar in design concept to a smokeless (ahem, see stainless steel...) fire pit.

 

Prepping for winter heating, I removed my Cat to check it over after burning all last winter. I was shocked, it barely had a layer of dust on it. I was expecting it to have visible dust and debris, but nothing. My cat glows during every fire. My understanding is, it's supposed to when there's enough gasses to warrant feeding it at those temps. After a glowing cat for the entire season and a crystal clean cat when inspecting it, don't figure I'll change a thing. One thing I wasn't prepared for, the gasket around the cat disintegrated after the cat was removed. I was assuming it was reusable a time or two. Nope! I'll pick one up on Monday.

 

It is.

 

It cleans up exhaust by combusting gases and particles, and creates heat in doing so.
Depending on the stove design that heat is extracted into the room or goes up the flue.

Some cat stoves have a cat e.g. in or directly below the flue. Those just put the heat into the flue. Here the cat merely functions as a cleaning approach.

A BK, or a Kuma have a exhaust path aims to have the heat transferred into the room.

There may be other examples of either approach.

 

My cat stove has a casted chamber around it where some of the secondary burning heat is recovered before going up the stack.

 

Attached is a picture of my Cat after my first full heating season, taken immediately after removing from the stove, without any cleanup.

 

I think I recall a thread where they said that a clean cat can be partially due to a low draft chimney...and one that is excessively ashed up can be from a high draft chimney.

 

In my AS I find as cezar above, that the smaller splits give more airflow paths and get that stove up to heat faster than biggies. However, once I'm up in the 450f'~500f' after that good 2-year plus wood and big splits are fine, although sometimes you don't get the stove stuffed tightly. For my needs the AS gives me plenty of hours even if I feed at 10PM there are still plenty of coals in there at 10AM.

The key ingredients are a good draft and dry wood. After that, it's how much air you give it to feed some ghost flames.