Am I expecting too much???

[Woodcutter Tom]

This is an insert stove? And a newer model IIRC...have any other 1500 owners chimed in on any of this?
I have Drolet 1400i, but its probably completely different...I know I haven't had any issues getting heat from it...

This not an insert. Stand alone stove. 2020 compliant.
Have not heard from other 1500 users.

 

[Woodcutter Tom]

I can't remember...have you verified that the baffle board above the secondary air tubes is properly in place?
Any chance that the primary air adjustment rod/linkage is bent/damaged in a way that doesn't allow it to close as far as it should?

I have verified the baffle board every time I load up with wood. Pressed back again the rear.
Regarding the primary air.....It actually has a hole in the plate that slides over the primary air opening. As the primary is closed over half way shut the hole opens more and more of the primary inlet. To me it seems the primary air is more open when fully closed that when 3/4 shut.

I remember playing around one time. I had the primary air somewhere between 3/4 and 7/8 shut. As I shut the primary air a very small amount the secondary flames decreased. As I opened the primary air, the secondary flames increased. Back and forth I decreased and increased the secondary flames. It was not a lot of secondary flames but they changed.

 

[brenndatomu]

To me it seems the primary air is more open when fully closed that when 3/4 shut.

I agree, that's weird

 

[TradEddie]

I can't believe we've got to page 2 before and nobody has suggested wet wood. I experienced it myself at the end of this season, and there is a huge difference between wood at 18% vs 22%. This year I also more fully appreciated the large error if mc is not measured at room temperature. Fresh splits from my stack measured 17% when cold, but up to 24% when allowed to warm to room temperature for a day before splitting. It's no problem to burn "wet"wood, but it just doesn't heat.

TE

 

[Woodcutter Tom]

I can't believe we've got to page 2 before and nobody has suggested wet wood. I experienced it myself at the end of this season, and there is a huge difference between wood at 18% vs 22%. This year I also more fully appreciated the large error if mc is not measured at room temperature. Fresh splits from my stack measured 17% when cold, but up to 24% when allowed to warm to room temperature for a day before splitting. It's no problem to burn "wet"wood, but it just doesn't heat.

TE

Most of my wood is walnut (10 -12% MC), hickory (13 -15% MC), and ash (13 – 15% MC). Always warm, split, then measure. Splits are on the small size. The larger pieces I have used lately are walnut at 18 .3% MC.

 

[brenndatomu]

Does this stove have an insulation blanket on top of the baffle? If it does, and it was out of place/bunched up, that could keep the STT down and the flue temp up (which will keep your draft numbers up too)
I'd be really tempted to put a piece of high temp foil HVAC tape partially over that primary hole, restrict is a little more, see what happens. I had a Vogelzang Defender that was an "easy breather", it responded really well to having all its various intake holes restricted by about 1/2...especially the primary air hole.

 

[Woodcutter Tom]

Does this stove have an insulation blanket on top of the baffle? If it does, and it was out of place/bunched up, that could keep the STT down and the flue temp up (which will keep your draft numbers up too)
I'd be really tempted to put a piece of high temp foil HVAC tape partially over that primary hole, restrict is a little more, see what happens. I had a Vogelzang Defender that was an "easy breather", it responded really well to having all its various intake holes restricted by about 1/2...especially the primary air hole.

No insulation blanket. Just the vermiculite baffle.
I may try that covering of the hole. I tried once with a piece of thin sheet metal. But I tried to move it in place with needle nose pliers and did not position it well. i think I have some of that tape here.

 

[brenndatomu]

A "metallic" magnet (not that flexible plastic magnetized stuff...like those magnetic business cards everybody hands out now) that can be slid over part of the hole would work too...

 

[Woodcutter Tom]

I cleaned out the stove yesterday. Removed the tubes, baffle, and all the bricks. I used a shop vac to force air through the secondary air passages. Air flows and I can't see or feel any obstruction. I just have to assume that there is no partial blockage that restricts flow. I cleaned up all the ash and scraped down any soot from the interior of the stove.

This stove has a steel sheet welded to the underside of the stove top. See attached photo. In the User manual there is a black line representing this steel sheet in one of the stove diagrams. I am guessing the sheet is .040 to .050 inches think. I do not know the purpose.

Here is my plan: I am going to add 2 feet back to the chimney height. That will put me at 14 feet above stove top. I want to get a bit higher above my roof line. Except for the southwest quadrant, every direction from my house is downhill. I do get winds here and I want to avoid the winds and roof pitch from effecting the draft.....as much as I can. With the stove empty, and a 6 mph SW wind and 52 F outside, I have a draft of .02. Manometer is calibrated to .00 with tube unattached. With a fire going, .03 - .05 may be problematic.
When the weather permits, I will start another fire. I would like it to be below 40 F. degrees. This morning it was 60F. I will load N-S with larger splits on the bottom and gradually use smaller as I stack the firebox. Once lit and a good fire is produced, I will use my primary air control the flue temperature. I will use the damper to try to keep the manometer reading under .06.

My concern has always been that when I close down the primary air, I do not get robust flames from my secondary tubes. Hopefully by controlling the draft, the unburned gasses will be ignited by the air from the tubes.

I am not going to tape off the primary air hole. After all, SBI has been making stoves for over 60 years, I don't have 60 months of experience. I have to trust they have a reason for this hole. (but I do have tape and a magnet handy)

I'm open to constructive comments.
I'll report back my results.

 

[ABMax24]

That sheet looks like stainless steel, my guess is SBI added that to avoid the cold steel top quenching the flames that go around the baffle, essentially to reduce emissions. This is a large part of why your stove doesn't get hot, that stainless sheet may touch the stove top in a couple spots, but definitely not everywhere, and will limit heat transfer. It's acting as an insulator between the fire and the stove top. Quite frankly I'd be pretty angry if I bought a stove that deliberately had a "bandaid" like that stainless sheet welded to it to meet emissions, because now the stove may pass emissions, but you are burning significantly more wood to achieve the same heat output.

In my opinion the more I look at what SBI did to make their stoves pass 2020 emissions the less impressed I become, in many cases they have achieved lower emissions by compromising the functionality and heat output of the wood stove. In some cases to the point I'd call their products wood incinerators, not wood stoves, I'm tempted to call this model an incinerator. To further illustrate my point not a single SBI stove qualifies for the 26% tax rebate as not a single stove exceeds 75% efficiency, the best efficiency any model achieves is 71%.

 

[MongoMongoson]

The sheet metal looks like a flame shield.
I have one on my Summit, centered. It does not cover the extent of the underside of the stove top like yours appears to, and mine is replaceable.

To the left and right of my flame shield, the stove top can be 100 degrees hotter than the center.

In response to ABMax24, there aren't many non-cat wood stoves on the EPA list at over 75%. I don't remember seeing any, in fact. I thought they were all catalytic and hybrid.

EDIT: my mistake, now that I look again I see them. I was also looking for a certain firebox size when I originally looked and that dropped the number drastically.

 

[ABMax24]

The sheet metal looks like a flame shield.
I have one on my Summit, centered. It does not cover the extent of the underside of the stove top like yours appears to, and mine is replaceable.

To the left and right of my flame shield, the stove top can be 100 degrees hotter than the center.

In response to ABMax24, there aren't many non-cat wood stoves on the EPA list at over 75%. I don't remember seeing any, in fact. I thought they were all catalytic and hybrid.

EDIT: my mistake, now that I look again I see them. I was also looking for a certain firebox size when I originally looked and that dropped the number drastically.

Yes the number of non-cats exceeding 75% is small, but there are 11 models that qualify.

 

[MongoMongoson]

I was looking for 3+ cubic feet of firebox when I first looked at the list.

Here's a current example of the STT difference, above the flame shield (centered on the ST), and to the left of the flame shield.
So yeah, that shield across the underside of the stove top. probably makes a heck of a difference.

 

[ABMax24]

To further this, there can be a difference in the coefficients of thermal expansion between stainless steel and carbon steel. If that plate is 300 series stainless it will expand much faster than the carbon steel plate above and will deflect away from the stove top, further limiting heat transfer. If the plate is 400 series the coefficient will be very similar to that of carbon steel, but even so the stainless will get hotter than the steel above and expand more, still deflecting away from the steel top to some degree.

The OP has the picture perfect flue setup per the manual, about 15' straight up to the cap. The flue temps are continuously being held in the 700-800F range and the STT doesn't exceed 500F. I see this as a heat transfer issue, not a combustion issue. The heat is being generated within the firebox, there's just no cool surface in the stove to transfer that heat to, so it heads up the flue. Which is exactly what will happen when 75% of the stove top is covered by a stainless steel sheet.

 

[gthomas785]

Sorry if this has been covered already but how are you measuring the temperatures? Especially the flue temp

 

[Woodcutter Tom]

That sheet looks like stainless steel, my guess is SBI added that to avoid the cold steel top quenching the flames that go around the baffle, essentially to reduce emissions. This is a large part of why your stove doesn't get hot, that stainless sheet may touch the stove top in a couple spots, but definitely not everywhere, and will limit heat transfer. It's acting as an insulator between the fire and the stove top.

Can't tell if it is stainless. A magnet sticks to it. But magnet also sticks to secondary tubes and they are stainless. I just learned that magnets can stick to some types of stainless steel.
The sheet only seems to actually touch the stove top where it is welded. I will call it spot welded as there is not a continuous bead around the sheet. I can see a tiny gap between the stove top and the sheet between each weld.

It does not cover the extent of the underside of the stove top like yours appears to, and mine is replaceable.

To the left and right of my flame shield, the stove top can be 100 degrees hotter than the center.

Mine covers the stove top to within an inch of each side- Left and Right. And fully front to back.

Here's a current example of the STT difference, above the flame shield (centered on the ST), and to the left of the flame shield.
So yeah, that shield across the underside of the stove top. probably makes a heck of a difference.

That's a big difference. And in a small area. Yours must be narrow.

 

[Woodcutter Tom]

Sorry if this has been covered already but how are you measuring the temperatures? Especially the flue temp

Flue temp measured by 2 inch thermocoupler Type K with 0 - 800 C range attached to a digital readout on PID. Probe is located 18 inches above stove top through double wall stove pipe.
Stove top by magnetic thermometer centered in front of stove pipe.

 

[Woodcutter Tom]

Quite frankly I'd be pretty angry if I bought a stove that deliberately had a "bandaid" like that stainless sheet welded to it to meet emissions, because now the stove may pass emissions, but you are burning significantly more wood to achieve the same heat output.

I could be quite angry, after all I have gone through this year. Been very frustrating and time consuming. But I am trying to 'Count to 10'. And get a full understanding. Thanks for the info.

 

[begreen]

Yes the number of non-cats exceeding 75% is small, but there are 11 models that qualify.

The mid-sized Pleasant Hearth is among that list. Trouble is, Pleasant Hearth does not sell that model any more. They no longer list their woodstoves in the menu. However, they do have a page for them with all new model designations and no EPA information that I can find so far.

Wood Stoves - Pleasant Hearth Fireplace Doors

Pleasant Hearth's non-catalytic wood burning stoves warm your homes in a highly efficient and effective way. EPA certified and efficiency ratings over 80%

pleasanthearthfireplacedoors.com

 

[Woodcutter Tom]

With all due respect, could we please keep this on topic. Thank you.

 

[ABMax24]

Can't tell if it is stainless. A magnet sticks to it. But magnet also sticks to secondary tubes and they are stainless. I just learned that magnets can stick to some types of stainless steel.
The sheet only seems to actually touch the stove top where it is welded. I will call it spot welded as there is not a continuous bead around the sheet. I can see a tiny gap between the stove top and the sheet between each weld.

300 series stainless is the only type that is non-magnetic, austenitic stainless is the more technical term, but even austenitic stainless can become magnetic if it is worked. The magnet could also be attracted to the carbon steel behind the stainless sheet. However it is quite likely that it is 400 series stainless, it handles high temperatures better, and is cheaper. I know my secondary tubes are 400 series.

If there is a gap that makes it worse off the get go, as we all know an air gap is a very effective insulator, being the principle behind double pane windows.

Not that it matters, but that is called a stitch weld, a spot weld is a resistance weld between two sheets without adding filler, car bodies have welds that are a common example of this. A stitch weld is a traditional weld, likely mig in this case, performed intermittently, likely to reduce cost and heat input distortion.

 

[brenndatomu]

That flame shield is nothing new for 2020...I had one on my 2012 built Tundra furnace...and it had popped a weld on the back left corner...seemed like maybe there was a layer of soot/creosote in between the 2 layers then, no way to get it out either...short of cutting the shield out...thought about doing that too, becuase the output of mine seemed less than what other guys were getting...my plenum temps (the wood furnace equivalent to stove top temps) were always lower than everybody else's...the guy I sold it to has a lower heat load then me, so he is perfectly happy with it.
My point is that there very well could be something to this shield not laying flat with the stove top...

 

[Sailrmike]

I could be quite angry, after all I have gone through this year. Been very frustrating and time consuming. But I am trying to 'Count to 10'. And get a full understanding. Thanks for the info.

You've been more patient than most, I like that you're willing totry anything including different flue heights. Operationally, I think you need to follow SBI's advice- do a hot, quick fire to establish a coal bed, do a FULL reload with larger sized splits, let it rip good (1000°F flue temp if needed) to fully char the load, and get your air setting as low as possible there after. That's how I get higher stove top temps. With smaller loads or if I don't let it char enough, i get similar temps to what you have been getting.

 

[Mike M.]

Most of my wood is walnut (10 -12% MC), hickory (13 -15% MC), and ash (13 – 15% MC). Always warm, split, then measure. Splits are on the small size. The larger pieces I have used lately are walnut at 18 .3% MC.

I am also am in suspect of the wood. Any moisture in the wood cools off the burn tubes, canceling out any chance of secondary burn. I would mix some pine 2x4s with the ash and give it another try. Remember you need a bed of coals raked forward in the stove, then add 6-8 splits on the coals. All my hardwood is tried 2 years and I have never seen moisture readings as low as yours. Something seems strange. 13-15% on hardwood almost needs to be dried in a Kiln or stored in a garage for 5 years. Most of my hardwood is 18-20% moisture and burns very well. Usually non-cats burn in the opposite manner, very hot in the beginning of the burn. For example, my experience is stove top temps range from 600-750 within the first hour or two of a fresh load.

 

[Woodcutter Tom]

Answer from SBI regarding sheet welded to bottom of stove top and it's purpose:

"Hello,
This sheet is a top protector.
It create an air shield between the stainless metal plate and the top of the stove.
Thank you."