Turning air up on non-cat as fire dies

[mar13]

I'm getting used to my new T5. I've read a lot about when to turn the air down, but what about turning the air up as the flue temperature drops?

I understand that non-cat fires are very cyclical. I monitor using both a Condar flue probe and stove top thermometers and place emphasis on the probe. During the day, I've also worn a path out the door to check on stack smoke emissions. My loads have been mostly cold starts with about 1/2 to 2/3 full. At a fire's peak, I'm typically at 25% air to keep the flue temp in the 550-700 range.

I'm wondering once the fire is on the downward slope with coals, some sunburnt wood, and smaller flames, should I be increasing the air to keep the flue temp in the "good" range, or just make sure I don't see smoke? I'm always erring on the side of a clean burn, but then I wonder if I'm wasting heat and my mental energy.

Caveats are that this question is for when I am around to tinker with the air and also not for full firebox loads. I recognize that turning the air up is a common trick for burning down coals before loading more wood.

On the Cal/Oregon coast, we're about to get hit by the roughest storm in quite a few years!

 

[barnaclebob]

What ive read is that once you're down to coals most of the creosote forming compounds are already burnt off so you dont have to worry about flue temp.

 

[Grizzerbear]

Unless i need more heat i will let the coals burn down with the air at same cruising setting. Kinda depends on heat needs really. The coals will not create creosote because all compounds are already spent as metioned above. Non cats are more cyclical as u said so unless it is quite cold outside i tend to have a lot more cold starts because i just dont need more heat for a while after a load is burned.

 

[billb3]

Beyond turning the air up to accelerate the longevity of the coals ( you can also have a new batch burn on top of them with a quick burning wood likeEW pine or poplar which will afford a new high temp secondary burn and still allow time for the coals to burn down), the coals require less combustion air so you'd want to actually turn the air down to decrease the air flow thru the stove and extend the coal burn time. This of course assumes you want an extended burn time. This ( just giving the coals time to burn) usually works great until it gets colder out and you need to start maximizing the higher output capability of the stove.

I usually don't worry about the coal phase air requirements. It's just too much fiddling. If I wanted to extract those last tiny bits of BTU out of the waning heat output I'd buy a stove with a thermostatic coil to control the air shutter like I used to have on the VC years ago.

 

[Woody Stover]

Unless i need more heat i will let the coals burn down with the air at same cruising setting. Kinda depends on heat needs really. The coals will not create creosote because all compounds are already spent as metioned above. Non cats are more cyclical as u said so unless it is quite cold outside i tend to have a lot more cold starts because i just dont need more heat for a while after a load is burned.

Right. This time of year, house temp holds pretty well and I don't mess with the air on the Keystone. If it's cold and windy, I'll open up the air at maybe 250 and the stove top will get back up over 300-325 for a few hours. I'm not there for the full burn cycle on the T5 so I don't know how much you can raise stove top temp by opening the air a notch. Plus we haven't had big loads in there yet, where we would have a big coal bed..we've been running 1/3 loads generally.

 

[Woody Stover]

I've also worn a path out the door to check on stack smoke emissions. My loads have been mostly cold starts with about 1/2 to 2/3 full. At a fire's peak, I'm typically at 25% air to keep the flue temp in the 550-700 range.

That's another thing I haven't checked as yet..if emissions change over the course of the burn. If you have a lazy secondary burn going when you first close the air to your cruise setting, are you finding that you can just leave it there over the rest of the burn, and still maintain a clean plume?

 

[David.Ervin]

Once you're at coals, the creosote forming stuff has been driven off and you're burning almost pure carbon. Don't worry about what the thermometer on the stove says, just look at the thermometer on the wall. If it's getting cold in the house, give it more air or add wood. If not, wait.