Flue temp verses stove temp

[Riddlefiddle]

Hi all. I have a question about stove and flue temps. I recently installed a used Jotul F 400 into a new Masonry chimney that is around 24' tall. I have been running it off and on learning how to use it. Anyways, I can't seem to get flue temps much above 280° even when stove top temp is at 500° or more on a reload or a cold start. I have been taking flue temps with IR gun 18" up from stove. Should I be taking temps down the pipe more? Maybe I'm not letting stove get up to temp hence the low flue temps. What reading do I go by for stove top temp? The IR gun or the temp gauge? Stove pipe is single wall.

 

[begreen]

Single or double wall stove pipe? Surface temps on single wall are much lower than actual flue gas temps. They can be 30-50% lower, so 280º stove pipe temp can be 560º flue gas temp which would be quite normal for a 600-650F stove top temp.

How far down are you closing the air on the F400 once the wood is burning robustly?

 

[Riddlefiddle]

Its single wall. I normally close it to half when stove top temp is around 400°. When it gets too around 500° I close it to 1/4. And then adjust from there.

 

[Riddlefiddle]

As far as stove top temps are concerned, do I go by what the IR gun Tell's me when I take temp from middle of stove top? Or do I go by temp gauge?

 

[begreen]

I go by the visual fire first and stove flue temps second.

 

[Riddlefiddle]

I brought up the question because when I took stove pipe apart to clean it looked like I had some creosote glaze in the wall crock. I try to keep flue temp over 250° but when secondary burn kicks in flue temps drop. I know this is normal but not much I can do about it.

 

[Doc C]

I've noticed that switching to The EPA stoves. Seems most of the heat stays in the stove and very little goes up the pipe. The only way I have found to get the pipe temp higher is to leave the damper on the stove cracked just ever so slightly.

Also since I started using some of the creoste products my pipe stays alot cleaner. Except at the very top. And the morning blazer of course probably doesn't hurt!

 

[Riddlefiddle]

What creosote products do you use?

 

[bholler]

I've noticed that switching to The EPA stoves. Seems most of the heat stays in the stove and very little goes up the pipe. The only way I have found to get the pipe temp higher is to leave the damper on the stove cracked just ever so slightly.

Also since I started using some of the creoste products my pipe stays alot cleaner. Except at the very top. And the morning blazer of course probably doesn't hurt!

Can you explain your burn technique to us? Do you bring the stove up to temp with every load or just with the morning fire.

 

[Riddlefiddle]

On a reload with a good bed of coals I run the stove up to 400° on the IR gun with air fully open. I then shut air too half and let temp rise to around 500°. By then wood is burning well and is charred to mostly charred so I reduce air to around 1/4. Secondaries are going by now. I let it burn down to coals and then reload when stove is below 350°.

 

[bholler]

On a reload with a good bed of coals I run the stove up to 400° on the IR gun with air fully open. I then shut air too half and let temp rise to around 500°. By then wood is burning well and is charred to mostly charred so I reduce air to around 1/4. Secondaries are going by now. I let it burn down to coals and then reload when stove is below 350°.

That sounds pretty good. I dont see why you are getting much creosote buildup.

 

[Highbeam]

Hi all. I have a question about stove and flue temps. I recently installed a used Jotul F 400 into a new Masonry chimney that is around 24' tall. I have been running it off and on learning how to use it. Anyways, I can't seem to get flue temps much above 280° even when stove top temp is at 500° or more on a reload or a cold start. I have been taking flue temps with IR gun 18" up from stove. Should I be taking temps down the pipe more? Maybe I'm not letting stove get up to temp hence the low flue temps. What reading do I go by for stove top temp? The IR gun or the temp gauge? Stove pipe is single wall.

Sounds normal. Skin temperature of single wall is half of internal temperature so your flue temps are actually 560. Usually stove temp and flue temp match once things are settled in. 500 is pretty cold though for a noncat plate steel stove, mine cruises at 700. Is the Jotul cast iron? Does it have a lower maximum temperature per the manufacturer or are you just running it so cold for another reason?

 

[bholler]

Sounds normal. Skin temperature of single wall is half of internal temperature so your flue temps are actually 560. Usually stove temp and flue temp match once things are settled in. 500 is pretty cold though for a noncat plate steel stove, mine cruises at 700. Is the Jotul cast iron? Does it have a lower maximum temperature per the manufacturer or are you just running it so cold for another reason?

All jotuls are cast iron. And 500 is not to cold at all.

 

[Highbeam]

All jotuls are cast iron. And 500 is not to cold at all.

I didn’t say 500 was too cold. Maybe you meant to quote someone else? I thought some Jotul stoves used welded steel boxes with cast iron cladding. Maybe I’m mixing up Jotul with Morso. Regardless, running that cold could be contributing to the creosote formation don’t you think?

 

[bholler]

I didn’t say 500 was too cold. Maybe you meant to quote someone else? I thought some Jotul stoves used welded steel boxes with cast iron cladding. Maybe I’m mixing up Jotul with Morso. Regardless, running that cold could be contributing to the creosote formation don’t you think?

Ok not to cold you said pretty cold. The op also is not complaining about creosote buildup. Just wants input on stove top temps.

 

[begreen]

Reaching far back but the F400 seemed to follow somewhat close to how our T6 performs WRT stack vs stovetop temp. This is what I have from the wayback machine.
450 stack probe = 550 stove top
average stack temps 250 - 450 (probe)
normal running stove top temps 400-600

 

[Riddlefiddle]

Yes its cast iron. I don't trust it yet. New stove for me, learning how it runs. Dam thing flared up on me the other day when wood shifted. Stove got up to 680°. Too hot for my likings. Therfore I try and keep Temp's between 5 and 6 hundred degrees. Creosote wasn't bad at all in stove pipe. The crock was where it seemed to have some creosote glaze. I will be checking chimney tomorrow to see how it looks.

 

[Doc C]

Can you explain your burn technique to us? Do you bring the stove up to temp with every load or just with the morning fire.

In the morning I get the stove and pipe about as hot as I possibly can within reason. After 10 minutes or so with the magnet thermometer on my pipe bordering on the red and sometimes just barely into it I shut the stove all the way down. This promptly drops the pipe temp below the yellow.

I let that load burn down to coals and let the coals sit awhile.

Then the rest of the day I throw wood in open damper until all the wood is charred and the the stove top temp is nearing the red on the stove top magnet thermometer. I shut the damper all the way down.

If the pipe drops below the yellow then I crack my damper maybe 1/2" which is usually enough to get the pipe into the yellow.

I have the proper thermometers in the proper places. Pipe thermometer on the pipe, 1 at about 6" and 1 at 18".

Also I have a stove thermometer on the stove top.

 

[bholler]

In the morning I get the stove and pipe about as hot as I possibly can within reason. After 10 minutes or so with the magnet thermometer on my pipe bordering on the red and sometimes just barely into it I shut the stove all the way down. This promptly drops the pipe temp below the yellow.

I let that load burn down to coals and let the coals sit awhile.

Then the rest of the day I throw wood in open damper until all the wood is charred and the the stove top temp is nearing the red on the stove top magnet thermometer. I shut the damper all the way down.

If the pipe drops below the yellow then I crack my damper maybe 1/2" which is usually enough to get the pipe into the yellow.

I have the proper thermometers in the proper places. Pipe thermometer on the pipe, 1 at about 6" and 1 at 18".

Also I have a stove thermometer on the stove top.

But if you are getting allot of creosote build up you need to run hotter that means you are not maintaining enough temp in the stack. Well that a nd the fact that silicone is fine on your pipe joints tells me you really are not running very hot at all. I would check the accuracy of your thermometer.

 

[Riddlefiddle]

I have temp gauge's in the same spots except for one at 6" above stove.

 

[Riddlefiddle]

My temp gauge is not accurate. Rutland. That's why I use the IR gun. I do need to get a better gauge. I could get flue temps to 300° but stove would get to dam near 600° before shutting air down.

 

[bholler]

My temp gauge is not accurate. Rutland. That's why I use the IR gun. I do need to get a better gauge. I could get flue temps to 300° but stove would get to dam near 600° before shutting air down.

600 is no problem at all it cas n even go higher. You should run your pipe temp up higher to start also.

 

[Doc C]

But if you are getting allot of creosote build up you need to run hotter that means you are not maintaining enough temp in the stack. Well that a nd the fact that silicone is fine on your pipe joints tells me you really are not running very hot at all. I would check the accuracy of your thermometer.

My guages are fine unless all 3 of them are equally bad. I have tested them against each other and they are all close in temp. The only place I get a decent amount of cresote is at the very top of my approximately 30' masonry chimney. That's to be expected. Since I switched to the smaller stove my creosote problem has all but disappeared. Now when I had the bigger stove I am lucky I didn't burn the house down!!

 

[bholler]

My guage are fine unless all 3 of them are equally bad. I have tested them against achieve other and they are all close in temp. The only place I get a decent amount of cresote is at the very top of my approximately 30' maaonry chimney. That's to be expected. Since I switched to the smaller stove my cresote problem has all bit disappeared. Now when I had the bigger stove I am lucky I didn't burn the house down!!

Ok i misunderstood from other threads it sounded to me like you had serious creosote issues. I am sorry for the misunderstanding.
I still dont understand why silicone works on your pipe though

 

[Doc C]

Ok i misunderstood from other threads it sounded to me like you had serious creosote issues. I am sorry for the misunderstanding.
I still dont understand why silicone works on your pipe though

I had a serious creosote problem when I had the Englander 30. I just couldn't run it the way it was designed as I would have to leave my house to let it cool off.

Since switching to the Englander 13 my creosote problem is almost gone...still trying to convert the glaze from the old stove but I'm not adding much new creosote.

Only thing I can think of on the silicone possibly since I don't know how other people apply it. I put my pipe together....then I smear the silicone overlapping it onto each side of the pipe joint. It's not pretty but it's effective. Maybe people get some silicone inside the pipe?? Not sure.