Optimum flue temps

[jadm]

I know I've read this somewhere but can't find it when I need it..

When taking a reading off of the flue at what temp. am I burning off creosote from my start up and then maintaining a burn that is as clean as possible.

My question excludes temps that indicate a chimney fire ......

 

[WoodMann]

It's been said that the optimum flue temp is in teh 300- 350* range. I'm still a noob so I can't confirm this as I get nervous if it gets over 250*. But the fella at The Firebird, the distributor for my stove, saysnot to worry, everything should be hot and to relax, but I tend to be cautous because I'm playing with fire..................

 

[RonB]

I always run my stack temp (as measured 18-24" above the stove) above 250. At reload time with a large wood load on hot coals it can push toward 500-600 for a while. These could be general guidelines for you. However, each setup will run a little different. I use my stove top gauge and the stove pipe gauge to better understand and correlate what is happening in the firebox. There are clues there that let you know that you are getting a clean burn. Do a search in the archives to better understand them. Some keywords would be clean glass, secondary burn, secondary tube color, and etc.

 

[jadm]

Thanks for the response. I just looked around on old threads and found out more about what I don't know.

I posted a topic awhile ago asking about the burning stages and now I need more clarification as to just what secondary burn cycles mean. I do get flames out of the tubes but it is not steady. Flames primarily down on my wood. Should they be staying up on the air tubes at some point and remaining there? What does it mean if flames aren't coming out of the tubes but the temps are around 550*? Do I need to push the temps higher to get the secondaries going?

My ignorance astounds me at times but I am an eager learner and do want to know more so thanks for educating me about this fire stuff.

I did read in one of the threads you recommended that by shutting down the primary air the temps. will bring on the secondaries and bring up the temps even higher.

When I tried shutting down the primary air by 50% the temps. didn't seem to budge so I opened it up again. Maybe I didn't wait long enough? On my old insert temps. would rise pretty quickly once I shut down the primary air and I usually shut it down 75%.

Patience....

I always run my stack temp (as measured 18-24" above the stove) above 250. At reload time with a large wood load on hot coals it can push toward 500-600 for a while. These could be general guidelines for you. However, each setup will run a little different. I use my stove top gauge and the stove pipe gauge to better understand and correlate what is happening in the firebox. There are clues there that let you know that you are getting a clean burn. Do a search in the archives to better understand them. Some keywords would be clean glass, secondary burn, secondary tube color, and etc.

 

[chrisman34]

It's been said that the optimum flue temp is in teh 300- 350* range. I'm still a noob so I can't confirm this as I get nervous if it gets over 250*. But the fella at The Firebird, the distributor for my stove, saysnot to worry, everything should be hot and to relax, but I tend to be cautous because I'm playing with fire..................

I was in your same boat! But trust me when i say this makes things worse Run it hot I run flue (outside single wall 12"up)to at least 300 before closing bypass at all, then close half way. Wait for it to climb to 400....then shut by pass and close air to about half.. Run there till cook top hits over 500 and back primary to a 1/4 open or so! MUCH MUCH less creosote! and that is what will cause a problem quicker than running hot! Clean chimney before changing habits, as I am sure you have a lot of creosote and may trigger a chimney fire if you just start doing this method.

 

[bokehman]

Do I need to push the temps higher to get the secondaries going?

You need above 1100F around the tubes for secondary combustion. If yourr wood is not properly seasoned your secondary burn won't work right because the dampness in the wood never allows these temperatures to be reached. I've got oak, seasoned for one year, and that won't sustain the secondary combustion with the damper closed. But if I put in some one-year-old pine or two-year-old oak and get it hot (750F off the glass) it will sustain the secondary with continuous flame until the wood reaches the coal stage.

 

[WoodMann]

I was in your same boat! But trust me when i say this makes things worse Run it hot I run flue (outside single wall 12"up)to at least 300 before closing bypass at all, then close half way. Wait for it to climb to 400....then shut by pass and close air to about half.. Run there till cook top hits over 500 and back primary to a 1/4 open or so! MUCH MUCH less creosote! and that is what will cause a problem quicker than running hot! Clean chimney before changing habits, as I am sure you have a lot of creosote and may trigger a chimney fire if you just start doing this method.

I did have a good deal of creosote in the pipe when I dismantled everything night B4 last to take off the air- mate hat. Good news is that the burning season is drawing to a slose over here so I can move back to the bedroom and start cleaning everything. BTW- I did get the flue up to 400* last night and, strangely enogh everything seemed just right; all the planets were in perfect alignment and heat seemed to be radiating all over like never B4. Well everything except the planet thing...............

 

[jadm]

Bokehman-

Thanks for the info. I keep playing with this thing and trying not to pull my hair out in the process. Will probably take me awhile before I get comfortable with just glass temps 550*.

Can you tell me what exactly the secondaries do? Are they creating even more heat in the box? Are they making it so even less smoke is being spewed out into the environment?

I guess what I'm saying is 'What function do they serve and why do these inserts have them?'

Do I need to push the temps higher to get the secondaries going?

You need above 1100F around the tubes for secondary combustion. If yourr wood is not properly seasoned your secondary burn won't work right because the dampness in the wood never allows these temperatures to be reached. I've got oak, seasoned for one year, and that won't sustain the secondary combustion with the damper closed. But if I put in some one-year-old pine or two-year-old oak and get it hot (750F off the glass) it will sustain the secondary with continuous flame until the wood reaches the coal stage.

 

[begreen]

The secondaries add air to the unburnt gases and burn them off. This creates more heat from the fire and a much cleaner burn.

As Martha would say, this is a good thing, a very good thing.

 

[jadm]

Thank-you. It is nice to not only enjoy watching my fire but to know what is going on in there too. I have survived another day with this baby and I still have wood left in my wood pile :coolsmile:

 

[Molson]

perplexed, I'm just getting used to my new stove too. Once the secondaries get going, its a great thing to watch. Over 600 degrees, the flames leave my wood and stay at the top near the tubes, its very cool.. On a full load for the night, my stove can get upwards of 800 degrees on the top before settling near the 550 mark for the night. It scared me a few times until I figured it was supposed to do that.