2024/25 VC performance discussion thread

[Turbo89]

You guys like living on the edge, I had 1 event about 1700-1750, and I went crazy troubleshooting.

Are you guys burning soaked wood or bad gaskets? Maybe try plugging a few secondary holes?

 

[56knoise]

Impressive you can keep cat temps that tight. I can tell the thing wants to go nuclear by all the dithering. I think your control loop could definitely benefit from some tuning. Loosen up the cat limits a bit and go to a proportional control loop with less gain.

Very impressive.

Thank you. I know it could be better, there are some bugs that I need to work out related to the remote monitoring and loss of internet connection but it has been extremely reliable so far. I'm sure I could get better control too with a better approximation of airflow and a better tune on the controller. I've managed to get the pid to hold tighter temperatures but the movements of the servo become aggressive and loud, the dog hates it and will run and hide in the other end of the house under a desk. The current values of kp 0.2, ki 0.1 and kd 0 keep it moving slowly and gradually and silent. I could replace the servo with something else like a stepper and an encoder but I've got too many other projects at the moment.

My theory on why closing the primary increases cat temps....

You have a thermal mass in there that is outgassing and making visible flame, when you reduce primary there is not enough oxygen to sustain the primary fire so what you get is a lot of smoke. That smoke encounters oxygen and a hot cat and combusts there. Temps go up until the thermal mass cools down and stops making so much smoke.

I think if you reduce the air slowly, in smaller bits overtime it will mitigate this.

What I can't explain is why sometimes I close the primary down and the cat temp goes up and stays up.... for hours.

That is the same conclusion I have reached. Any time the flame goes completely out and it smolders the cat wants to climb as high as it can and the stove cools down significantly. Good for overnight burns if you can control it but playing with the air and ensuring there is active flame in the firebox is much better for actual heating and keeping the cat under control.

Does your stove have the EPA holes near the front legs? They are 1/4 diameter and on both sides going into the ashpan area, always letting some air into the system which might explain your closed primary air and rising temps. I've plugged one of the holes on mine and it helped, I keep another plug ready for the other side just in case it decides to runaway due to an air leak or something.

 

[arnermd]

"a few 1750's" Does your pipe go red hot like mine did? I think mine only got to 1746 or maybe 1748.

My exhaust pipe has never glowed.... Thats usually not my problem. I have seen exhaust temps in the 1200 region but they are pretty short, maybe 10 min max. My exhaust alarm is set to 850 and it rarely goes off. If I have a runaway cat and open the damper the stack temp will launch very quickly to 1000 - 1200 but that's expected.

 

[arnermd]

You guys like living on the edge, I had 1 event about 1700-1750, and I went crazy troubleshooting.

Are you guys burning soaked wood or bad gaskets? Maybe try plugging a few secondary holes?

I don't think anybody "likes" living on this edge... been troubleshooting for 12 years..... Plugged secondary's and it helps calm things down but not 100% effective.

 

[arnermd]

Thank you. I know it could be better, there are some bugs that I need to work out related to the remote monitoring and loss of internet connection but it has been extremely reliable so far. I'm sure I could get better control too with a better approximation of airflow and a better tune on the controller. I've managed to get the pid to hold tighter temperatures but the movements of the servo become aggressive and loud, the dog hates it and will run and hide in the other end of the house under a desk. The current values of kp 0.2, ki 0.1 and kd 0 keep it moving slowly and gradually and silent. I could replace the servo with something else like a stepper and an encoder but I've got too many other projects at the moment.

That is the same conclusion I have reached. Any time the flame goes completely out and it smolders the cat wants to climb as high as it can and the stove cools down significantly. Good for overnight burns if you can control it but playing with the air and ensuring there is active flame in the firebox is much better for actual heating and keeping the cat under control.

Does your stove have the EPA holes near the front legs? They are 1/4 diameter and on both sides going into the ashpan area, always letting some air into the system which might explain your closed primary air and rising temps. I've plugged one of the holes on mine and it helped, I keep another plug ready for the other side just in case it decides to runaway due to an air leak or something.

Control loop tuning is always balancing act.... Looks like you got a good system there.

EPA Holes: My stove has one in the bottom just in front of the primary flapper. I think its about 3/8" dia. I have plugged it with no real noticeable effect. Just to be clear, my over-temps are never on the primary side, Griddle is always 350 - 650.

 

[GrumpyDad]

Still havent finished the floors thus haven't installed the baseboards. Was to be a spring time project in this cabin I built but then our world was turned upside down so everything was put on hold.
Little Dauntless loves oak. Even though the stove looks like it's consumed most of the wood that was in there, it could run like this for several more hours without touching it. This is my window thermometer so the room was probably more like 74. It went down to -11 that night.
Cat probe sits perfectly in the middle. Air control at 70%.
For such a little stove, it loves to cruise.

 

[badgerfire]

So I'm wanting to get one of the fancy cat thermometers for my VC Dauntless from Auber Instruments.

A couple questions - are these the right things to get?

Is there an installation guide anywhere for how to set this up with a Dauntless? I have saved a couple threads on here where people are discussing these thermometers so I could probably just piece it together from there...

In an "explain it to me like I'm five" situation - the "thermocouple" (WRNK-191) goes in the stove where the current thermometer is and then some wire(s) come from that to the AT100TC thermometer and that displays the temp.

What is generally a good operating range for the cat? Reading the VC Dauntless manual, it says it starts working at 500F but no upper range and of course the "thermometer" included with the stove doesn't have numbers (just a white shaded zone labelled "Operate Catalyst"). Once we get this thing working, I want to have some sort of idea what an optimal range is. 800-1000?

Thanks!

 

[Turbo89]

So I'm wanting to get one of the fancy cat thermometers for my VC Dauntless from Auber Instruments.

A couple questions - are these the right things to get?
View attachment 336188
Is there an installation guide anywhere for how to set this up with a Dauntless? I have saved a couple threads on here where people are discussing these thermometers so I could probably just piece it together from there...

In an "explain it to me like I'm five" situation - the "thermocouple" (WRNK-191) goes in the stove where the current thermometer is and then some wire(s) come from that to the AT100TC thermometer and that displays the temp.

What is generally a good operating range for the cat? Reading the VC Dauntless manual, it says it starts working at 500F but no upper range and of course the "thermometer" included with the stove doesn't have numbers (just a white shaded zone labelled "Operate Catalyst"). Once we get this thing working, I want to have some sort of idea what an optimal range is. 800-1000?

Thanks!

it looks like you picked the meter and added a sensor option, so you don’t need to buy another sensor.

There’s lots of folks on here with more experience than me, but folks seem to like to keep temps below 1650 as to not damage the catalytic element and run them between 1000-1450. I belthe VC manual says they start to be active above 800 deg, but I’m going from memory.

I posted some pics a few weeks ago about installing one in an Encore. Perhaps they’ll be useful for you, but it’s a different stove?

 

[Woodsplitter67]

So I'm wanting to get one of the fancy cat thermometers for my VC Dauntless from Auber Instruments.

A couple questions - are these the right things to get?
View attachment 336188
Is there an installation guide anywhere for how to set this up with a Dauntless? I have saved a couple threads on here where people are discussing these thermometers so I could probably just piece it together from there...

In an "explain it to me like I'm five" situation - the "thermocouple" (WRNK-191) goes in the stove where the current thermometer is and then some wire(s) come from that to the AT100TC thermometer and that displays the temp.

What is generally a good operating range for the cat? Reading the VC Dauntless manual, it says it starts working at 500F but no upper range and of course the "thermometer" included with the stove doesn't have numbers (just a white shaded zone labelled "Operate Catalyst"). Once we get this thing working, I want to have some sort of idea what an optimal range is. 800-1000?

Thanks!

This looks correct, I didn't look it up but before you order make sure your k type thermocoupler is to 2k degrees.. as the sell the same one only to 1000 I believe

 

[Megunticook]

What is generally a good operating range for the cat?

According to Condar, the North Carolina company where I get my cats from, 1000-1700 is the operating range. I've followed that (mostly!) and my cats have lasted years (except for year 1 when I blew through the cat out of ignorance). They say to go ahead and close the damper at 500, but it takes a while to get the probe up to 500 on my Encore with the damper open, so I generally close it when griddle reaches 500 and then the cat probe will reach 500 in a minute or two. Usually after about 5-10 minutes I'm up at 1000 and I try to settle things in at 1000-1300.

 

[badgerfire]

Super! Thanks for the replies! I'll get it ordered (make sure to just get one sensor and a thermocouple that is good to 2k).

 

[Eman85]

That's the correct meter AT100TC which includes your choice of sensor and you want the WRNK-191.

 

[arnermd]

According to Condar, the North Carolina company where I get my cats from, 1000-1700 is the operating range. I've followed that (mostly!) and my cats have lasted years (except for year 1 when I blew through the cat out of ignorance). They say to go ahead and close the damper at 500, but it takes a while to get the probe up to 500 on my Encore with the damper open, so I generally close it when griddle reaches 500 and then the cat probe will reach 500 in a minute or two. Usually after about 5-10 minutes I'm up at 1000 and I try to settle things in at 1000-1300.

When they say "close the damper at 500" they mean the griddle temp, not the cat temp. With the damper open it will be hard to get the cat to 500 (impossible on my stove) because there is very little flow through it.

I generally close mine around 450 on the griddle but if the stove is already hot you can close it at lower griddle temps. Depends on the age of the cat too...older cats are less active and may need more griddle temp to light off.

5-10 minutes to 1000 seems pretty quick to me (but I have a bigger stove), you might try throwing the damper at 450 or even 400 and see if it gives you better control over your cruise temps.

 

[Megunticook]

When they say "close the damper at 500" they mean the griddle temp, not the cat temp. With the damper open it will be hard to get the cat to 500 (impossible on my stove) because there is very little flow through it.

I generally close mine around 450 on the griddle but if the stove is already hot you can close it at lower griddle temps. Depends on the age of the cat too...older cats are less active and may need more griddle temp to light off.

5-10 minutes to 1000 seems pretty quick to me (but I have a bigger stove), you might try throwing the damper at 450 or even 400 and see if it gives you better control over your cruise temps.

Condar doesn't actually say "close the damper at 500," the temp. probe monitor just says "500-1000: engage catalyst." But you're right, in practice this means griddle temp since the cat probe isn't going to really heat up until after the damper is closed.

I was just sort of guessing on the time it takes to hit 1000--never actually timed it with a watch. But it doesn't take long. I typically start cutting down the primary air as it hits 900 or so just so as not to overshoot too much. But actually things are running really great with the stove, I feel like I have good control and I never really have issues with things getting too hot now. Just have to be careful not to overload the stove with too much wood, especially smaller hardwood splits, as I do seem to have a small airleak at one of the seams (will address it this summer) and if I filled the firebox right full with seasoned hardwood I'd likely get into overfire territory.

 

[Turbo89]

I've been meaning to report back here with my little project and this seems like a good time. I owe you guys big for helping me completely rebuild this stove several years ago. It was completely disassembled down to the smallest part and completely rebuilt by my hand.

So, I've been using an ESP32 and a few other parts to constantly monitor and control my stove.

The thermocouples in the flue, catalytic converter and griddle monitor everything and keep the temperature within safe limits. The potentiometer adjusts the desired cat temp (900 to 1500 degrees).

There's a soft overheat limit where the butterfly valve on the air intake will shut and a hard overheat where a very loud peizo alarm starts going off. I can monitor the temperatures and see graphs on my phone and it will (soon) send me texts if it overheats or if I need to add wood (The variable for "FEED ME SEYMOUR" is triggered when catalytic temp drops below 800). The numbers on the displays will also start to blink as it approaches the overheat limits.

The adapter for the butterfly valve is 3d printed out of ASA and uses a servo for positioning. The valve has a silicon seal on the inside and seals very well. I also had to weld together an adapter to go from the square air intake to the round butterfly valve housing which turned into me drilling a hole in the wall and turning it into an outside air intake.

I also have it hooked up to a backup battery in case the power goes out. I usually leave the air flow on the stove at the half way mark just so if something goes terribly wrong it doesn't get full airflow but it has now been 3 years with no maintenance and it has worked flawlessly after some PID loop tuning and firmware fixes.

There's plenty of room for improvements and size reduction but I haven't seen a need to rebuild the thing just yet. This is version 2, version 1 was purely monitoring. The big red button silences the piezo alarm for 30 seconds, the led with a piece of paper taped over it is lit when it has an active internet connection and the switch to the right is a hard override and completely shuts down the air supply. The center is just a potentiometer for setting the target cat temperature with a silly oversized knob.

How are you regulating the controls (PI controls)? And what’s the logic look like? Do you have a more in depth post on this (here or elsewhere)?

Cool looking setup, and your burn results are impressive. I wonder if fine tuning the controls would remove “peaky-ness” or if it would hurt burn length?

 

[badgerfire]

We have an IR gun that we'd like to use on the stove top. With VC and their fancy enamel, I'm trying to find the right emissivity setting. Specifically, we have the bordeaux (red) enamel Dauntless. I tried to find some tables online to see but didn't have a ton of luck.

Any chance another VC owner with the red color happens to have set their emissivity on an IR gun?

Thanks!

 

[JohnDaileyNH]

Snowing again here. Every 3/4 days for the last few weeks we seem to get 5+ inches. This one is going to finish with some ice which will be fun. Encore just keeps chugging along. Going to use a lot of wood which is fine. It's actually a real NH winter.

 

[arnermd]

As I sit here this morning in full firefighting mode... a new thought occurred to me. Is it possible that the bimetal thermostat can get so hot that it starts opening the primary flapper? Something that has not occurred to me before.....

This weekend I replaced my primary air flapper, and replaced my griddle gasket. For three days the stove ran pretty good, occasional peaks to 1600 but I was dialing that down by blocking fire back holes. This morning I did my usual reload, not quite packed, started dialing air down as cat came up through 1000 and had it cruising at 1200 with maybe 10% air open. A couple hours in all hell broke loose, heard the tell tale combustion noise, closed the air all the way and shut my key damper, magnets on the primary flapper. Cat peaked at 1843, stack 1341..... It was over 1600 for about an hour or so... inconsolable. Will post the data later.

About an hour before the event I whispered to to my wife, "the stove has been running great". It must have heard me.

 

[Eman85]

About an hour before the event I whispered to to my wife, "the stove has been running great". It must have heard me.

We've all said that it seems with similar results.
It's turned cold here and have been burning 24/7 again after a pretty good break where I let the stove go cold and cleaned everything. I've has similar where I felt I was the master of the fire. Hot reloads challenged me as I had the cat drop a lot as I closed the air down even doing it gradually and letting the cat go to 1200-1300 before shutting air. Had the cat drop to 600 on me and I would open the air and let it get to 12-1300 again and it would be fine after that. A couple of nights ago I reloaded and all was good, went to bed about 2 hours after reload so I felt confident it was good. Woke to the smell of burning wood as the stove had a big back puff. Rain had moved in and it was pouring out, I guess the heavy warm air effected the stove. I opened the air a little and went back to bed and all was fine after that. 1843 is very high, I don't like anything past 1500.

 

[arnermd]

Check out this mornings crap show.....

This is data over the last 3 days since I replaced the griddle gasket and primary air flapper.... was decent, until it wasn't

 

[arnermd]

Just realized.... part of the issue is I just broke into a row of Ash. Before yesterday I had been burning primarily red oak.
Fresh split at room temp, along the grain shows 12-14% moisture content.

 

[dmccoole]

Just realized.... part of the issue is I just broke into a row of Ash. Before yesterday I had been burning primarily red oak.
Fresh split at room temp, along the grain shows 12-14% moisture content.

That's what happen to me when I went from oak to maple. I only put on a few splits at a time now until I get through the maple

 

[Woodsplitter67]

Well it looks like the partys over for me. I've enjoyed what feels like 3 months of pretty much nonstop burning..

With the temperatures coming and the sun angle getting higher Ill probably have to start a fire in the evenings now. Kinda sucks

On a good note.. my split pile looks like this.. like 7ft high

 

[arnermd]

Well it looks like the partys over for me. I've enjoyed what feels like 3 months of pretty much nonstop burning..

With the temperatures coming and the sun angle getting higher Ill probably have to start a fire in the evenings now. Kinda sucks

On a good note.. my split pile looks like this.. like 7ft high

Good looking pile.... lots of nice heartwood.

I personally can't wait to shut my stove down, seems like for 6 weeks the stove and I had a tenuous peace accord where it stayed below 1650 most of the time..... but the last week it has been full on fighting. Cat temps over 1700, back puffing into the house seems to occur with every load now in the middle of a burn with no adjustments from me. Only change is the wood, from red oak to some ash. I have resorted to throwing on 2 med splits when the cat drops below 900, every 4 hours or so.

I am getting too old for this kind of stress, the other night we went out for dinner and I could not enjoy myself becuase I was worrying about what the stove was doing. I have stopped loading up the stove at night becuase I want some sleep so the house is colder in the mornings, fortunately there are still enough coals to light off the next half load in the morning.

I am seriously considering alternatives, looking at a Hearthstone Manchester and the Blaze King Ashford. Unfortunately neither have all the features of my VC Defiant, but I am hoping they burn better. Bought some gasket rope for the doors and ashpan, even though they seem fine I will swap them out and see if that changes anything. This may be the last straw for this stove.

 

[dmccoole]

Good looking pile.... lots of nice heartwood.

I personally can't wait to shut my stove down, seems like for 6 weeks the stove and I had a tenuous peace accord where it stayed below 1650 most of the time..... but the last week it has been full on fighting. Cat temps over 1700, back puffing into the house seems to occur with every load now in the middle of a burn with no adjustments from me. Only change is the wood, from red oak to some ash. I have resorted to throwing on 2 med splits when the cat drops below 900, every 4 hours or so.

I am getting too old for this kind of stress, the other night we went out for dinner and I could not enjoy myself becuase I was worrying about what the stove was doing. I have stopped loading up the stove at night becuase I want some sleep so the house is colder in the mornings, fortunately there are still enough coals to light off the next half load in the morning.

I am seriously considering alternatives, looking at a Hearthstone Manchester and the Blaze King Ashford. Unfortunately neither have all the features of my VC Defiant, but I am hoping they burn better. Bought some gasket rope for the doors and ashpan, even though they seem fine I will swap them out and see if that changes anything. This may be the last straw for this stove.

I don't know how you've made it this long! For me, having a cat temp at 1746 and a glowing red stove pipe one time was almost too much for me, but almost every night? Especially after all the rebuilding and tweaks of your stove over the years. I've been getting the back puffing quite frequently in the middle of a burn as well. Maybe because its maple? But it shouldn't back fire.

I'd sacrifice a feature or 2 for the peace of mind and to have the better feature of not burning down the house.