How hot should the casting get?

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Swtorguy

New Member
Nov 17, 2021
6
US
Hello, long time lurker, first time poster. I have a VC Dauntless 2020 without the cat kit. Had one installed, choked the fire way way way too much so now I don’t. Anyway, the temp of the stove inside the upper casing on the top of the stove on both sides of the flue collar (inside the heat shield), hits about 700F just inside on an IR gun while the rest of the stove remains 400f with the damper and emits that hot metallic smell. I get that secondary burn chambers get hot, but to get the flue collar that high… Something doesn’t seem right to me here. Also them the air control is 1 click from closed when this happened. I’ve checked for leaking gaskets all around and it’s tight. Anyone got any ideas or is it even a problem?
 

kennyp2339

Minister of Fire
Feb 16, 2014
6,551
07462
Seems normal, maybe a hair on the higher side of things. All temps are measure on the outside of the stove right? not in the actual firebox?
 

Woodsplitter67

Minister of Fire
Jan 19, 2017
2,236
Woolwich nj
No one measures the temperature on the inside of the stove. If you read the manual it will tell you that the griddle temp should be like 650 outside. Your flue temp should also be taken on the outside I take mine at the top of the oval adapter that meets the stove pipe. Im not sure of what your saying you cut the air way back and are not doing that any more. Are you saying that the stove came non cat and you put one in..
 

gthomas785

Minister of Fire
Feb 8, 2020
670
Central MA
It sounds like you are saying the cat choked the fire down so you removed it and now it's too hot.

Well first of all the cat should make the stove produce more heat not less, so you might want to figure that one out

But secondly a flue collar temp of 700 is not at all unusual mid burn cycle. The cast flue collar is highly radiant so it will throw off a lot of heat and I have seen that spot as high as 800F with a flue pipe temperature (internal) 18 inches away of only 500F. It's normal.
 

Swtorguy

New Member
Nov 17, 2021
6
US
It’s the outside, not inside. The stove pipe is a double wall, so the surface temp on those is useless (unless it’s smoking and above 300). Anyway, when the griddle reads 450 and 4 inches beyond that is 700 and climbing… Seems suspect to me

Not a fan of that burning metal smell or the sound the secondary makes when its high. Propane torch noises should accompany propane torches…

The VC Dauntless is a “flex burn”. You want it to act like a cat stove, buy a combuster and put it in. Want non-cat, leave it out. Sounds like I’m either gonna have to learn to live with it, stress out about it burning the place down or replace it. Thanks.
 

kennyp2339

Minister of Fire
Feb 16, 2014
6,551
07462
It’s the outside, not inside. The stove pipe is a double wall, so the surface temp on those is useless (unless it’s smoking and above 300). Anyway, when the griddle reads 450 and 4 inches beyond that is 700 and climbing… Seems suspect to me

Not a fan of that burning metal smell or the sound the secondary makes when its high. Propane torch noises should accompany propane torches…

The VC Dauntless is a “flex burn”. You want it to act like a cat stove, buy a combuster and put it in. Want non-cat, leave it out. Sounds like I’m either gonna have to learn to live with it, stress out about it burning the place down or replace it. Thanks.
Ahhh I better understand where your coming from now, you may want to install a probe pipe thermometer into the double wall to get a more accurate flue gas reading.
How tall is your chimney? and whats your location to get a better understanding of temps, elevation, primary wood species. If you have at tall chimney (past 28ft) you may want to consider adding a key damper to slow things down, also the propane torch noise from the secondary's, you sure its coming from them and not an air leak at the flue collar?
 

begreen

Mooderator
Staff member
Nov 18, 2005
93,868
South Puget Sound, WA
We don't know much about the Dauntless's burn characteristics yet. This may not be unusual if it is happening at the peak of the burn. Stove temp is usually measured several inches away from the flue collar. At peak fire, 700º does not seem alarming. How tall is the flue system on the stove?
 

Swtorguy

New Member
Nov 17, 2021
6
US
Ahhh I better understand where your coming from now, you may want to install a probe pipe thermometer into the double wall to get a more accurate flue gas reading.
How tall is your chimney? and whats your location to get a better understanding of temps, elevation, primary wood species. If you have at tall chimney (past 28ft) you may want to consider adding a key damper to slow things down, also the propane torch noise from the secondary's, you sure its coming from them and not an air leak at the flue collar?

I’ll check out that probe temp. Thanks.

Chimney is 24’. East central Vermont +1100 ft. I have been burning kiln dried hardwoods, beech, oak and the like that was dropped off, stacked and covered in May 2020.
No I’m not 100% certain about the noise location. It’s always bottom center on the rear sounding, and gets louder as the secondary chamber probe temp climbs to the right, or past, the “operate catalyst” zone. If I stick my hand over the intake, the sound dampens but it isn’t coming from the intake. The manual says “If you hear a rumbling or roaring noise (like a propane torch) from the stove, that is a sign that the stove is over-firing.” Given the griddle was 400f, the secondary probe was headed to the right and everything above that chamber was redlining and that sound appears when I close the damper and it’s over 350, I made an assumption.

So far, I am finding this stove to be a veritable pain in the ***, with a double order throw in for free. I’m probably gonna call the dealer and chimney guy tomorrow, get them out here together and hash this mess out. It’s probably just a standard ID-10T error, but it’s best to make sure.
 
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begreen

Mooderator
Staff member
Nov 18, 2005
93,868
South Puget Sound, WA
Put a key damper in the stovepipe. That will help regulate the draft. The bottom rumble is not untypical of VC stoves. It's where the afterburner action is.
 

gthomas785

Minister of Fire
Feb 8, 2020
670
Central MA
If the temp is climbing past the "operate catalyst" zone then you need to either feed it less wood or give it a bit more primary air before cutting it back. Can you describe a little more about your operating procedure and everything you did before the temp gets that high. If the griddle is only 450, then it sounds like either you cut back primary air too early or your wood is wet.

I don't get the propane torch sound on my VC stoves but I don't operate them without the catalyst so that could be the difference. So far nothing you've described sounds particularly concerning to me except the combustion chamber temps.

Surface temperatures on the stove exterior will vary widely and that's why you always have to specify, griddle temp, flue temp, etc. 300 degrees from griddle to flue collar is not uncommon.

The griddle also will read low if you shoot it with an IR gun because of the finish.
 

Swtorguy

New Member
Nov 17, 2021
6
US
If the temp is climbing past the "operate catalyst" zone then you need to either feed it less wood or give it a bit more primary air before cutting it back. Can you describe a little more about your operating procedure and everything you did before the temp gets that high. If the griddle is only 450, then it sounds like either you cut back primary air too early or your wood is wet.

I don't get the propane torch sound on my VC stoves but I don't operate them without the catalyst so that could be the difference. So far nothing you've described sounds particularly concerning to me except the combustion chamber temps.

Surface temperatures on the stove exterior will vary widely and that's why you always have to specify, griddle temp, flue temp, etc. 300 degrees from griddle to flue collar is not uncommon.

The griddle also will read low if you shoot it with an IR gun because of the finish.
Cleared ash, left char clups, emptied ash pan. Usually, I do the top down fire starting, but this time I did the campfire/log cabin bit to build a coal base using kindling. 20min or so later, pushed the coals to the back and added 2 larger, 2x16-ish splits in a cross and let them burn to coals. after about an hour, pushed the coals and unburnt wood to the back and added 4 splits ranging from 2inches to 5 inches. The cat probe was in the white zone (only zone on the probe) so I closed the damper and every 5 min adjusted the air control lever 1 click back., stopping at 5 clicks. So almost 2 hours from cold to this point. Way way too much time spent babysitting a stove in my opinion.

Air control on this stove is 9 positions. Full front is wide open, full back is closed.

Temp stabilized at 450 on the griddle, cat probe was in the white So I walked away. About an hour later, I could smell that acrid “hot metal” smell on the other side of the house, so I went to check. Stove was making that propane torch sound, griddle temp was 400, cat probe was pegged full right. Grabbed the IR gun and started checking temps in various places and found the flue collar at 700+ and the 1st tube of the stove pipe at 350 on the outside of the dual wall pipe.

The stove pipe is a 16 inch segment, 3 inch collar, 7 inch segment, collar, a 90 bend into a 45 bend then the wall.

The wood moisture probe was showing between 8% and 12% moisture.

The reason for the change in how I started it was becasue the manual (https://downloads.hearthnhome.com/installManuals/3-90-586000c_Dauntless FlexBurn_Consumer.pdf) listed this method. Figured why the heck not.
 
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Todd

Minister of Fire
Nov 19, 2005
9,609
NW Wisconsin
That does sound like too much babysitting and too hot flue temps. Sounds like once she gets going she creates an overdraft, probably need a pipe damper For more control but I would prolly play around with it a little more.

Since this is a down draft stove I bet a top down fire start isn’t as effective as the traditional methods. Maybe try starting off with a good pile of kindling only to establish a good coal bed, rake them to the back then fill with the amount of splits you feel you need and let it go through the whole burn cycle before adding more wood. I’ve read these downdraft stoves can be finicky and you may need a lot of trial and error to learn these stoves.
 

gthomas785

Minister of Fire
Feb 8, 2020
670
Central MA
I agree it's plausible that your draft could be over spec based on how tall the chimney is.

What was the fire doing when you observed / smelled the secondary overfiring? were there still flames in the front?

I don't believe your moisture readings. How did you get those. Are you re-splitting a room temp piece of wood to measure in the center?
 

begreen

Mooderator
Staff member
Nov 18, 2005
93,868
South Puget Sound, WA
A log cabin style fire build might be ok for wood that is marginally seasoned, but as demonstrated it is not something to do with bone dry wood because there's a lot of air gaps in between the wood with accelerates ignition. Instead, pack the stove tightly and try to minimize air gaps.