Can't control my stove on reloads

[thunderhead]

I had a T5 installed less than a year ago, and it is proving nearly impossible for me to keep under control the last couple weeks. It is 40 degrees out. I have a 20 foot chimney. Just now I waited until stovetop temp was 290 degrees and my auber flue probe was at 360 degrees. I put in 4 medium large splits, loaded north-south, on a small bed of coals, raked forward. I made sure the load did not have easy air flow between the 4 splits. This is not quite a full load, as I have been struggling to control this stove on reloads, although it is close to a full load. After a couple minutes, flue probe hit 550 and I started closing the air in increments, with the flue probe at about 760, fully closed, 10 minutes later. The secondarys take off and the stove rockets to a flue probe peak of 1230 degrees. Most of the flame is in the form of a huge, aggressive, secondary. I could have sworn I did everything decently this time, rapidly closing, with a little less than a full load, after loading on a coolish late-stage bit of coals. What should I check or do next? Is it leaking air somewhere? We have never used the ash pan, and it is controllable on cold starts and partial reloads. One catch is I forgot the species of wood. MC% is around 20%. It is not maple, cedar, or doug fir... it is medium density... similar I think to doug fire, maybe a touch lighter. Is there a species of west coast wood that is known for going nuclear like this? Is the draft too high?

Thanks!

 

[thunderhead]

Should I... strategically place a magnet in a certain location?

 

[begreen]

Hemlock is also common around here. I would try closing down the air sooner. You could also try blocking off the boost air port. It should be front and center on the bottom of the stove just under the front of the firebox.

The fact that this is new behavior may indicate a door gasket issue. When the stove cools down, exam the door gasket closely. Make sure it is still glued in the gasket channel. I have seen some of these come unglued after a year. If it has come unglued, gently tease it out of the channel in that area and apply some black or red RTV adhesive there to glue it back in place. Then close the door and let it sit for 12-24 hrs.

 

[Highbeam]

A stove and design well known for being an easy breather and suitable for short 12’ chimneys is a stove that could have too much draft on a 20’ chimney.

Is this the classic Florida bungalow syndrome?

I assume that draft was never measured and there is no damper installed.

 

[thunderhead]

I didn't watch the entire install, but it was never measured while running, that's for sure. I was thinking of getting a manometer... that is a probe that I briefly stick in the connector pipe, right? It is a 20 foot stack... mostly straight up... no damper... just one 30 degree offset... but compared with some other stories on this forum that sounds like its a middle of the road stack height... and temps never get all that cold here. It does have outside air... does that make the flue pull harder?

I'll also check the gasket and do a dollar bill test the next time it cools down but I have never had good luck keeping things quiet on reloads. A few weeks ago I thought I was having a "breakthrough" and running it well overnight... but my success was limited and fleeting. That batch of wood I was getting overnight burns with might have been from a wetter portion of my wood. Alas I am new to this and my wood is not yet perfect and is very mixed, so that adds another layer of variability to this. I didnt realize burning wood would have so many variables! It is pretty fun though... except for the last few overnight attempts... hah.

 

[Highbeam]

I didn't watch the entire install, but it was never measured while running, that's for sure. I was thinking of getting a manometer... that is a probe that I briefly stick in the connector pipe, right? It is a 20 foot stack... mostly straight up... no damper... just one 30 degree offset... but compared with some other stories on this forum that sounds like its a middle of the road stack height... and temps never get all that cold here. It does have outside air... does that make the flue pull harder?

I'll also check the gasket and do a dollar bill test the next time it cools down but I have never had good luck keeping things quiet on reloads. A few weeks ago I thought I was having a "breakthrough" and running it well overnight... but my success was limited and fleeting. That batch of wood I was getting overnight burns with might have been from a wetter portion of my wood. Alas I am new to this and my wood is not yet perfect and is very mixed, so that adds another layer of variability to this. I didnt realize burning wood would have so many variables! It is pretty fun though... except for the last few overnight attempts... hah.

By any chance, did any of those pieces that caused the runaway look like this one? Our evergreen trees can have lots of pitch. When that stuff boils off you can get some hot fires! 20’ is a tall stack. Way over the minimum required by any manufacturer that I’ve read. Thing is, the pollution people want all of this wood gas burned before it leaves the chimney so they’ve forced stove designs that burn it even at the expense of user control.

 

[ejsechler]

Try turning down your stove sooner if that doesn't help you may have to put in a inline damper.

 

[begreen]

20' is a normal stack size and maybe a bit under for a 2 story house depending on where the stove is installed. Our stack is also 20'. The draft is just about perfect. If our stove was more central in the floorplan the stack would be about 24'.

Check the door gasket to make sure it is glued in properly and also make sure that the ash trap has closed tightly. Sometimes a chunk of coal can get stuck in it, preventing full closure. And keep trying to close down the air sooner. If none of these steps help, then you could also try blocking off the boost air intake hole. It is on the center bottom, directly under the front edge of the firebox.

 

[thunderhead]

By any chance, did any of those pieces that caused the runaway look like this one? Our evergreen trees can have lots of pitch. When that stuff boils off you can get some hot fires! 20’ is a tall stack. Way over the minimum required by any manufacturer that I’ve read. Thing is, the pollution people want all of this wood gas burned before it leaves the chimney so they’ve forced stove designs that burn it even at the expense of user control. View attachment 269076

Nah, i couldnt see much sap in it, nothing like that. If there is one way i would describe this mystery wood is the bark looks like cedar, but the interior looks maple. It is more dense than cedar though, and slower drying.

 

[rwhite]

Sounds like hemlock.

 

[coreboy83]

I have the same stove, LE model. 19' flue. This has happened to us, twice. I chalked it up to not turning the air down soon enough.
Its not my wood, it was not a high wind day. I have become accustomed to turning the air down "a little too much, a little too soon" or else this will happen. It's like I wrote your responses, same temp : I pinned at 1250 for 10 minutes.

 

[begreen]

Our stove is on a 20' flue system. I closed off the boost air. With dry wood and good kindling we have never needed it. I leave the door ajar a little for a cold start, but that's all.

 

[thebaron23]

Our stove is on a 20' flue system. I closed off the boost air. With dry wood and good kindling we have never needed it. I leave the door ajar a little for a cold start, but that's all.

Does the boost air on T5/T6 not feed the secondaries?

Ive got a newer EPA2020 T5 and was told the secondaries were fed exclusively by the boost hole so by blocking it I'd starve the secondary.

Is that incorrect? If it is I'm going to try closing it down 1/8 at a time because I pin my double wall probe at 650/700 with the air controller closed all the way.

If I leave my air open even 1/8 of an inch I'm redlining. No leaks in my gasket either just way too much draft on my 20 foot straight pipe.

 

[begreen]

Does the boost air on T5/T6 not feed the secondaries?

Ive got a newer EPA2020 T5 and was told the secondaries were fed exclusively by the boost hole so by blocking it I'd starve the secondary.

Is that incorrect? If it is I'm going to try closing it down 1/8 at a time because I pin my double wall probe at 650/700 with the air controller closed all the way.

If I leave my air open even 1/8 of an inch I'm redlining. No leaks in my gasket either just way too much draft on my 20 foot straight pipe.

Yes, that is incorrect. The EBT2 has it's own holes. This is not the same as the boost air at the front of the firebox. However, I have not had my hands on the new T5 LE yet so I will have to rely on you to do a little inspection when the stove is cold. Look at the very front, bottom inside of the firebox. Are there a series of small holes there? You might want to use a mirror to inspect.

 

[coreboy83]

. Look at the very front, bottom inside of the firebox. Are there a series of small holes there? You might want to use a mirror to inspect.

Yes, there is an angle of thick steel running the width of the firebox opening that can be tilted out. On the underside, inside the ash pan, there is a wee little hole next to the blade that operates the air intake. Can this hole be covered with hvac tin tape to try to correct ?

 

[thebaron23]

Yes, that is incorrect. The EBT2 has it's own holes. This is not the same as the boost air at the front of the firebox. However, I have not had my hands on the new T5 LE yet so I will have to rely on you to do a little inspection when the stove is cold. Look at the very front, bottom inside of the firebox. Are there a series of small holes there? You might want to use a mirror to inspect.

At the very front of the box there's the large hole that the main air controller slides over and to the right of it there's a round hole about 1 inch dia. I assume that's the boost air hole, the other day when the stove was cold and we had the dryer running there was a cool draft coming in from it.

I've stuck a magnet on it covering half the hole up for tonight, seems to have my stack temp down to 600 from 650-700. I'll try it a few days to get some decent data points before completely covering it.

 

[begreen]

If you can take a shot of that area with a cell phone I'd appreciate it. Don't hesitate to cover it completely as a test for a burn cycle.

With Covid-19 I have not visited any stove shops this year at all. First time in over a decade. Of course this would be the year when there is a flood of new stoves on the market and Tom Oyen has retired. I'm itching to get out and have a look at the new models. I helped a neighbor set up a T6 LE. Maybe I will see if they would let me check it out now that it's installed.

 

[thebaron23]

If you can take a shot of that area with a cell phone I'd appreciate it. Don't hesitate to cover it completely as a test for a burn cycle.

With Covid-19 I have not visited any stove shops this year at all. First time in over a decade. Of course this would be the year when there is a flood of new stoves on the market and Tom Oyen has retired. I'm itching to get out and have a look at the new models.

Sure can!
I assume the partially magnet covered hole is the boost. There definitely was a draft coming out of it the other day when the dryer was running and the stove was cold.

I can take other pics of it if you'd like. Just might have to wait till it's cooler to get more intimate with it, I'm dripping sweat just getting that one lol

 

[thunderhead]

Are you folks trying to keep the secondaries lit as you turn down the air? Or is it ok for them to temporarily go out(or maybe not have started)? When i turn down from full open to say, 75% open, i often do that before the secondaries are lit. Should i keep turning the air down before the secondaries light up, or is that burning too dirty?

Also i did a dollar bill test and looked over the door gasket. No problems there.

Thanks!

 

[thunderhead]

Are there a series of small holes there?

Yes, mine has a few there. Three, i think, although I'm not reaching in there right now to verify the count...

 

[mar13]

If I correctly recall the parts diagram, the ebt2, which feeds the baffle, is stand alone, in the rear, and not associated with the air boost.

I have 20+ straight chimney with the T5, but one of the last non-LE. With alder and temps around 40, I've been doing the initial turning down before there are much, or even any, secondaries. Once at 50%, I'll make sure both primary and secondary flames don't get snuffed significantly as I decrease air further. My secondary air, however, is proportional , to some degree, to my primary air by a linkage system, unlike on the LE stoves.

 

[mar13]

Has anybody with an over drafting model with an EBT2 consider covering one of the side port holes on the EBT2 to reduce the maximum secondary air? I'd imagine, however, the air boost hole, which doesn't directly feed secondary air via the baffle would be a more sensible approach. (Arguably messing with a stove's design is rarely sensible.)
Here's a video of the ebt2.

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[thunderhead]

I'm not as experienced as these other folks but I'd think the secondary flow is the flow we would always want strong... as that is where the clean burn comes from? I think i might try to block half the boost air with a magnet... then all if that doesnt work.

 

[coreboy83]

I think i might try to block half the boost air with a magnet... then all if that doesnt work.

I'm wondering if any magnet will work, or can a piece of hvac tin tape be used ?

 

[moresnow]

I used magnets for experimenting. Tinfoil as well. I've also had magnets fall off when super heated. Not good for a permanent solution in my case but worked great for testing.