The Watlow's were rescued from a dumpster at work. The data logger I bought specifically for diagnosing my stove issues. The Watlow's are much more capable than what I am using them for (Type K TC readouts and alarms) they are meant to be heater controllers and can do PID control. I have toyed with the idea of buying some electric actuators and using them to control air off of stove temps. Would be a fun project but seems silly..... Someday maybe when I run out of more sensible projects. 😁
2022/23 VC Owner thread
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Sure - I think I have the signature figured out now but an Encore 2040. First season. We’re recovering from trust issues after seeing the factory probe rotated 180 degrees from 0 (well beyond the silver band) before I figured out that the primary air was stuck full open. The Auber helped me immensely.
Getting dialed. I can see myself joining the full time fire heat club in the future.
Woodsplitter67
Minister of Fire
Woodsplitter67
Minister of Fire
The body/size of the stoves are the same, but they run a little different
the older encore picture 1.. has a lower burn and not quite as high of a burn as the 2024 and a lower efficiency rating
picture 2.. the 2040 has a high efficiency rating but the low burn is a little higher and the higher burn is a lot higher at 65k BTUs
picture 3 the 2040cat c.. has a slightly higher low burn then the other 2 previous stoves the higher burn is not as high as the original 2040 and the efficiency of the stove is higher than the 2 previous stoves but only 4% above the original 2040 in cat mode i believe
the original 2040 was changed to meet to 2000 emissions standards..
Well..... things went off the rails last night
Had a lot of coals still so I opened up the air and let that cook down for an hour, knocked down a lot of ash and left it in the pan. Loaded up a full load, had some pretty big splits in there.
The griddle and flue temp came up very quickly in bypass mode. I noticed there was very little yellow flame visible compared to earlier good runs. Plenty of orange glow at the bottom though.
I reduced air to hold the stack at 400, looking for some flames to break out, but they never really did. Finally just threw the cat in and things seemed fine for a while. Cat was tracking ~1200 till it launched.
Bringing the primary air down to 0% of drove the cat initially lower then hotter. At this point I closed the key damper all the way. Stove slowly cooled, but then I opened the primary air and it really fell off.
This is a great example of how opening the primary can bring down cat temps, but only after I closed the key damper. I think what happened here was I reduced the secondary air flow (by reducing draft) and then increased primary air flow flow thus shifting the burn to more primary (less secondary) because the primary burn was more complete (more primary oxygen, less fuel for the cat).
I managed to get the flue gasses back down to 400 range so I decided to experiment by just cracking the key damper. Cat launched again and I was able to rein it in by closing the key damper. I think this is pretty solid evidence the problem is at least exacerbated by high draft levels. I did some sporadic checks on draft levels while cat was at 1600 and they were near the levels I had before my damper mod, 0.12 - 0.13 iwc. With the damper full closed I had readings in the 0.08 - 0.09 iwc range. Last night was the coldest night we have had in a while so that is likely contributing to excess draft.
Questions that come to mind:
Had a lot of coals still so I opened up the air and let that cook down for an hour, knocked down a lot of ash and left it in the pan. Loaded up a full load, had some pretty big splits in there.
The griddle and flue temp came up very quickly in bypass mode. I noticed there was very little yellow flame visible compared to earlier good runs. Plenty of orange glow at the bottom though.
I reduced air to hold the stack at 400, looking for some flames to break out, but they never really did. Finally just threw the cat in and things seemed fine for a while. Cat was tracking ~1200 till it launched.
Bringing the primary air down to 0% of drove the cat initially lower then hotter. At this point I closed the key damper all the way. Stove slowly cooled, but then I opened the primary air and it really fell off.
This is a great example of how opening the primary can bring down cat temps, but only after I closed the key damper. I think what happened here was I reduced the secondary air flow (by reducing draft) and then increased primary air flow flow thus shifting the burn to more primary (less secondary) because the primary burn was more complete (more primary oxygen, less fuel for the cat).
I managed to get the flue gasses back down to 400 range so I decided to experiment by just cracking the key damper. Cat launched again and I was able to rein it in by closing the key damper. I think this is pretty solid evidence the problem is at least exacerbated by high draft levels. I did some sporadic checks on draft levels while cat was at 1600 and they were near the levels I had before my damper mod, 0.12 - 0.13 iwc. With the damper full closed I had readings in the 0.08 - 0.09 iwc range. Last night was the coldest night we have had in a while so that is likely contributing to excess draft.
Questions that come to mind:
- Why did the griddle come up to temp so quickly? I am not really sure, must have been some fire going in there, maybe I just could not see it?
- Did I take the griddle too hot, wait to long to engage the cat?
- Did the lack of ash contribute to the problem? I will let it build up again and see if it affects the problem.
- Maybe with colder weather I need to run with the key damper more closed?
- A barometric damper would really be ideal here.... except I really do not want to dump cold air into my stack.
- Debating making up a pipe section with a baro damper in it that I can try, temporarily.
Woodsplitter67
Minister of Fire
Its been warm recently so I cleand the stove cleaned the cat, removed the cat, just had a small fire here and there, just put cat back in as its a little colder
So heres something interesting. the past 2 nights iv been burning my overnight fires. only half loads starting around 6pm I load the box with a few large splits cats at 1007, I go to be later, cats at 825 which is ok because the loads off gassing I wake up at 6am.. stoves still going... granted its in the low 200s but I dont have to reliight the stove in the morning.. pic 1 was yesterday morning.. pic 2 is this morning
Kinda neat to get up in the AM and have a 12 hour burn on a small amount of wood
So heres something interesting. the past 2 nights iv been burning my overnight fires. only half loads starting around 6pm I load the box with a few large splits cats at 1007, I go to be later, cats at 825 which is ok because the loads off gassing I wake up at 6am.. stoves still going... granted its in the low 200s but I dont have to reliight the stove in the morning.. pic 1 was yesterday morning.. pic 2 is this morning
Kinda neat to get up in the AM and have a 12 hour burn on a small amount of wood
Woodsplitter67
Minister of Fire
Hav you considered only allowing you stovepipe to get to 300 instead of 400.. this will reduce your draft, reducing the amount of draft going through the secondary chamber, reducing the cat temperature and such high cat temps during the burn cycle
Maybe your magic number is more like 250/300
It is nice to see you guys getting closer and closer to utopian burn cycle😝. These downdraft stoves are soooo sensitive to some many variables (baro pressure, outside air temp, wind speed and dir., split MC, split size, split volume, split placement, ash level, stove body temp at reload…..bla bla bla).
I remember mine would go 2 wks with perfect behaviour. Every reload would almost behave the same. Nice 8-9h burn, cat hovering at 1350, griddle at 450-500 and pipe probe at 350-375. Life is good😝. Then bam same reload procedure and a “melt down”. Head scratcher for sure.
I remember mine would go 2 wks with perfect behaviour. Every reload would almost behave the same. Nice 8-9h burn, cat hovering at 1350, griddle at 450-500 and pipe probe at 350-375. Life is good😝. Then bam same reload procedure and a “melt down”. Head scratcher for sure.
Woodsplitter67
Minister of Fire
You should find another VC stove somewhere and put it someplace so we can all talk more...
I think I am good. But you know, I am like you guys, if something does not work I will do anything to make it work. And then…..it becomes an obsession😜. My obsession started in 2007 when I bought VC Defiant Encore 2450 (i think) the famous “Everburn” downdraft non-cat stove. The VC engineers thought they hit a jack pot with this one!
What a disaster stove that was……My struggles were documented in this thread, few thousand pages back😝😝. As stated above, with my completely rebuilt 2550 I would still get an occasional melt down. I do not need another VC in order to (to some extent) contribute here. That stove (s) is burnt into my brain no punt intended😝
That option was not on my list.... it is now. Not sure I can hold it that low.... but I will try it and see.
Questions:
- Is the cat at 1000 when you put the splits on? Or you put the splits on and took the cat to 1000?
- What was the air setting when you left it alone?
- What do you mean by "relight"? Strike a match?
- Do you typically "relight" your stove every day or just with smaller loads?
- I almost never have to strike a match, almost always enough coals in the bottom to catch with the doors open. All my matches get used in October and April. Used one last week I think. Stove will go 24 hours and still catch the next load, no matches.
Woodsplitter67
Minister of Fire
they run a little hotter in the back to get the new epa standard.. from what I understand..
Woodsplitter67
Minister of Fire
So when you get your stovepipe up to that temperature.. your increasing your draft by a lot..
Woodsplitter67
Minister of Fire
So last night I got the stove warm enough to obviously run, but didn't crank up draft ect.. my stove was roughly 500 and stovepipe probably 275/300ish. my cat was roughly 700.. I added wood like 3/4 large splits. Closed bypass right away waited for cat to shoot to 1000 degrees and turned the air all the way back.. the cat started to crash( which is expected) cat went down to 800 ish.. ( its ok if the cat crashes but not stall) Cat slowly combined back to 1000 and stayed there for a number of hours.. I finally went to bed and looked at the aubor on my way to the bedroom and cat was roughly 850 and burned throughout the night.. cat temps will drop as the wood offgasses and there is less fuel for the cat to burn.. woke up at 6am and that was what I have in the box
This is the advantage of the cat stove.. righ now my stove is still running with the air all the way back.. It will run all day today like this.. I added a little more wood when I came in from splitting.. cat is in the upper 600s
Woodsplitter67
Minister of Fire
Here are pictures of my stove running as described above.. cat temp is 672.. stove is at 333 degrees.. shot with IR gun.. stove pipe is 226 degrees.. shot with IR gun..
No smoke out of the stack.. If I loaded the stove with wood and the cat temp is this low you can expect smoke and creosote build up because the offgassing will overwhelm the cat.. with a smaller load of wood you don't overwhelm the cat and burn clean..
No smoke out of the stack.. If I loaded the stove with wood and the cat temp is this low you can expect smoke and creosote build up because the offgassing will overwhelm the cat.. with a smaller load of wood you don't overwhelm the cat and burn clean..
Woodsplitter67
Minister of Fire
Did some splitting this morning.. My son and I have been hitting it here and there for a couple hours
Woodsplitter67
Minister of Fire
This is interesting. This goes along the lines of how I believe the secondary thermostatic air control should work. I'm a little gunshy and lazy so I really don't want to let my cat run free if I can help it. But when I have had it take off and I missed it when I checked it the secondary air shutter was open and the cat temp was dropping. Still wanting to find the engineer that designed this part of the stove.
Whenever I try to dilute the air to the cat by opening the primary more, as some suggested, the cat really builds temps fast and when it gets over the 1500 mark I cut the air. I have been able to control my cat but it does take time to get it where the cat and I are comfortable and I can go to bed.
Ok was going to ask this. So I usually follow your process then my cat crashes at 1000 when I shut the air and then I would open it back to try and maintain and hold the 1000. Sounds like I dont have to do this.
How can I tell the difference between crash and a stall? I always assumed this was the cat stalling out
Air all the way back?
Like the skid steer. I bet that's handy. I got my Kubota which is a great little machine but that skid steer looks like a real workhorse.
Yeah I think for you guys with secondary bimetal control, as the secondary closes it will reduce the secondary air flow....obviously. But I suspect it actually increases the primary air flow at the same time because there are two streams in parallel. If the draft is a fixed pressure then closing off one of the parallel streams will increase flow in the other one. Seems to make some sense to me, it is shifting oxygen from the secondary to the primary.
Where I get mystified is how does this work with the 2n1 fixed restriction secondary...... baffles me.
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