How can I get my stove top temperature up higher without overfiring the flue pipe?

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jackerama

New Member
Feb 1, 2023
18
Ohio
Hi, I'm new to wood burning and am trying to dial in my new stove. I have a Jotul F600. We are experiencing a cold snap right now and the stove is struggling to keep the house warm. I can't seem to get the stove top to go above 500F without the flue temp getting too hot. The stove is installed in the rear vent configuration and I am measuring surface temp of the horizontal pipe coming out of the stove with an IR gun. When I am trying to increase the stove top temperature it doesn't take long for the stove pipe to hit 500+. FYI I am measuring the top corner of the stove top as recommended in the Jotul manual. Thank you very much.
 
First thing is how’s your wood? Is is seasoned to 20% or below? Do you have a moisture meter? If so take a split that has been indoors for a day or two and resplit it and put the probes parallel to the grain middle of the split.

I’m not familiar with your stove but as I gradually lower the primary air my STT increases.
 
Hi, I'm new to wood burning and am trying to dial in my new stove. I have a Jotul F600. We are experiencing a cold snap right now and the stove is struggling to keep the house warm. I can't seem to get the stove top to go above 500F without the flue temp getting too hot. The stove is installed in the rear vent configuration and I am measuring surface temp of the horizontal pipe coming out of the stove with an IR gun. When I am trying to increase the stove top temperature it doesn't take long for the stove pipe to hit 500+. FYI I am measuring the top corner of the stove top as recommended in the Jotul manual. Thank you very much.
The draft gets stronger when the temperatures outside get very cold. If the draft is good at 40º it can be very strong at 15º. How tall is the flue system on the stove? Is it straight up through the house or does it feed into a thimble via an elbow?

The other thing to watch is air leakage underneath the fire via the grate because of a leaky ashpan gasket or because buildup behind the ashpan is pushing it forward, preventing a good ash pan door seal. I ran our F400 with the ashpan full and never used it. Instead I scooped out the ash via the front door. This made a nice improvement in burn time and overall controlability in spite of this being a new stove.
 
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@Wildflush I just ran out of my good wood supply which I assume should have been plenty dry because its been seasoning for a couple of years. I'm burning slightly less than ideal wood right now but I will be getting some more seasoned wood tomorrow and will report back with MC numbers and if anything changes.

@begreen There is about an 18 inch horizontal run with 6" pipe that goes into an increaser and cleanout tee then straight up an 8" insulated liner in a masonry chimney for about 35 feet.
 
OK, my suspicion is that after that very tall chimney has warmed up, it starts sucking like a Hoover. If that is the case, a key damper in the horizontal section should help tame draft. The downside of doing this may be that in 40º weather the stove spills smoke on startup until the chimney warms up. Even when it is open, the key damper will restrict a bit of airflow. If this is the case, preheating the flue for 5 minutes with a hair dryer or heat gun. may be advisable.
 
Get a meter if you don’t have one. I use one from Harbor Freight. The only way you know if your wood is good. Wood over 20% does not burn as hot.
 
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That sounds like good advice! Thank you both. Will the damper help the stove top to heat up more relative to the stove pipe by sending less heat up the chimney?
 
@begreen is the expert on key dampers. Believe he is testing one this season on his stove.
 
Yes, 35' high will likely require a damper.

FYI - I plan to start a new thread in the next day or two after I get done with some experiments with my air intake and damper that will probably be boring but maybe help some folks...
 
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Yes, 35' high will likely require a damper.

FYI - I plan to start a new thread in the next day or two after I get done with some experiments with my air intake and damper that will probably be boring but maybe help some folks...
NickW looking forwarding to reading your assessment. I have read the thread on key damper theory but his stove is much different than mine.
 
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NickW looking forwarding to reading your assessment. I have read the thread on key damper theory but his stove is much different than mine.
@Highbeam just had a very important note in that thread about each setup being different. Even though he & I have the same stove we will probably have different settings because of flue and environmental differences. My thread will hopefully show how small differences in operation can have large effect on performance.
 
@Highbeam just had a very important note in that thread about each setup being different. Even though he & I have the same stove we will probably have different settings because of flue and environmental differences. My thread will hopefully show how small differences in operation can have large effect on performance.
Are your stoves cat? I know @begreen has a PE non cat.
 
@Wildflush I just ran out of my good wood supply which I assume should have been plenty dry because its been seasoning for a couple of years. I'm burning slightly less than ideal wood right now but I will be getting some more seasoned wood tomorrow and will report back with MC numbers and if anything changes.

@begreen There is about an 18 inch horizontal run with 6" pipe that goes into an increaser and cleanout tee then straight up an 8" insulated liner in a masonry chimney for about 35 feet.
You need a damper in your pipe. Your draft is too strong and it's pulling to much heat up the chimney