2023/24 VC Temperature discussion thread

[Woodsplitter67]

Question from reading Novembers posts. Stove is a VC Encore, wood is very seasoned (12%) and stored inside of dry building. Flue is 6" 27' with exceptional draft compared to wood stoves I've ran in the past with 16 'flue.

So we built new home and wanted wood stove in case of emergency, but also I like to work with firewood. Last season i figured out i had to get the fire going , then within 15 minutes shut air off as tight as possible to keep extra strong flue draft from overheating stove and especially catalyst ( no temperature reading, just going by white zone on dial in back of stove).

Cutting air off gave me smooth 4-5 hour burns that heated a 3000 sq ft home very comfortably (75 main room, 72 most of house). Problem was/is I would get some dark glass and very gentle puff backs as the hot fire was just a little too starved for oxygen IMO.

So, seeing cold air is headed to Ohio next week, I tried to open the air up a bit this morning. As the fire gained in heat, it eventually started puffing again, this time more forceably, I'm assuming because it was larger and more intense but still incapable of burning all the released gasses with the amount of oxygen im feeding it? This time the back fires have caused smoke into the room, thankfully Moms not home to appreciate my pyrotechnics on display.

So my primary questions are
1- is the cat really too hot when outside the white painted area?
2- am I burning it wrong starving it for air before just as the wood gets ignited well?

I weigh my wood, and burn 120lbs per day on an average 35 degree winter day. That equates to about 547,000 btu's actual heat if stove is converting at 80% efficiency. This number is almost exactly what it takes on a similar temperature day to heat with propane. Propane use is 6.4 gallons per day at 93% efficiency yielding the same 550,000 btu's.

So draft is based on how hot the stovepipe is and also outside temperature. So even though you have 27ft of stovepipe your draft will get stronger as the stovepipe heats up and weaker as it cools. Your backpuffing is from a buildup of gasses, the best thing to do is avoid that air setting and if it happens.. increase the air slightly

I would avoid the Bimetal probe.. get a albur at100.. digital probe and k type thermo coupler.. youll get exact readings and will be able to see in real-time whats happening.

Cutting the air back is the advantage of any cat stove.. so your not wrong in doing this.. you just need to learn to set the air to avoid the back puffing

 

[Eman85]

I think everyone with a VC stove that has a top load gets the infamous back puff of smoke in the house. I think every stove does it but VC's with the top load the puff in the stove pushes the griddle up to allow the smoke out. I have had my stove back puff when I'm burning with the cat or without if I starve the box for air and there is enough fuel that is outgassing.
Dark glass is just because you burned low and slow, the dirty smoke stays in the box, this is what causes the dirty glass and the back puffs.
4-5 hour burn isn't very long with the air cut off, should go 8-12 with enough wood. I don't cut the air completely off, I will have it open about 10% to avoid the back puffs. My Encore is old but it takes an 8" pipe.
The Auber probe and meter is the way to go for monitoring temps. I bought the AT100C which comes with a thermocouple and it uses the standard mini connector.

 

[Rusty18]

If it don’t puff out the top plate they will puff out the air intake. Ask me how I know…

 

[AsylumResident]

Very sorry to hear this story..... I know exactly how you feel, amazing how similar our experiences are.... but you have drained all hope for me. I think there is no cure, the stove is what it is.

I do have one suggestion for you, make a plate to cover the secondary inlet completely and get some magnets to hold it in place. It will kill your secondary temps when all else fails and you can leave the damper closed.

As I was working through my pile of ash I was burning small loads 1/2 or less with 60% air and that helped. Still managed to get it through the night and avoid striking a match. I am now back to mostly red oak and it seems like I can't keep the cat lit...... 100% air till cat gets to 1000 then I throttle it down to 60% and cat temps drop to 550-600 in an hour..... always something. Might be reduced draft due to warmer temps and some buildup in the stack.

Yes, I need to make that plate. It's been on my list.

 

[AsylumResident]

So far my stove has been remarkably easy and predictable. It's been rolling 24/7 since I cleaned and reloading hot and cold. The colder reloads I just wait for STT to rise to 500 and close the damper. Still doing things the same with closing the air down but I've been letting it run to 1100 then closing the air to 10%. Cat will drop down to the 900's or so and then rise nicely to the 1200-1400's depending on the size of load. It will burn nicely and cat temps drop slowly. If I'm around I'll open the air more to keep the cat hotter and get a little more heat from the stove. I've been using the max temp recorder feature of the Auber and highest has been in the 1400's. My wood is mixed, has some ash, cherry. oak, walnut, hickory and locust probably some ironwood and any other thing I cut.

Just kicking a man when he's down. Salt on the wound 😉

 

[AsylumResident]

If it don’t puff out the top plate they will puff out the air intake. Ask me how I know…

I'm guessing you put your "VC stove God idol" on the griddle to make sure it didn't pop up with the back puff.

 

[Eman85]

Just kicking a man when he's down. Salt on the wound 😉

Didn't mean it like that. I was struggling last year when the cat was new and I didn't control it properly. I'd go from a good burn to bad with what seemed like no control over the cat. Total anxiety over runaway cat temps. Since I started cutting the air back at 1000 to 1100 and letting it drop then rise it seems easier to control. Now my stove is antique and is the first generation of VC cat stoves, not sure if yours has any differences in how it would operate. I have a secondary air intake and asked a lot of questions about it last year but never got any definitive answers even from VC and dealers. I didn't modify mine at all just replaced the thermo coil and made sure the flap and linkage was free.

 

[AsylumResident]

Didn't mean it like that. I was struggling last year when the cat was new and I didn't control it properly. I'd go from a good burn to bad with what seemed like no control over the cat. Total anxiety over runaway cat temps. Since I started cutting the air back at 1000 to 1100 and letting it drop then rise it seems easier to control. Now my stove is antique and is the first generation of VC cat stoves, not sure if yours has any differences in how it would operate. I have a secondary air intake and asked a lot of questions about it last year but never got any definitive answers even from VC and dealers. I didn't modify mine at all just replaced the thermo coil and made sure the flap and linkage was free.

I understand, Just giving you a hard time.

 

[Rusty18]

I'm guessing you put your "VC stove God idol" on the griddle to make sure it didn't pop up with the back puff.

Nope, pot with about with about 2 gallon of water in it. FYI griddle temps mean nothing with a bug post of water setting on the door!

Hoping to get the stove fired up this evening but currently Have a 2.5 year old napping on me…I don’t dare wake her up… you think the vc’s are temperamental

 

[Eman85]

FWIW my stove hasn't gone cold since I cleaned the chimney on Jan. 1. We let it burn the coals down during the day if it's warm, so far warm has been in the 50's mostly, throw in a split or 2 during the day. Then build it up around supper and final load is at 10PM so I can get it cruising by bedtime around midnite. Mornings are usually frosty so I open the air and get the cat rising again burning up what's left and cleaning the glass. Then load what I want, engage the cat, and turn the air down when cat crosses 1,000-1,100. If I'm sitting there drinking coffee once the cat peaks, 13-1400 range and starts dropping I'll give it more air if I want the house warmer. That's the one thing about a cat stove is it would be nice if it could control air after the cat peaks to keep the heat up a little higher.

 

[arnermd]

Another rager last night....

• Yesterday I let the stove coast on a heavy bed of coals
• Loaded 2 med splits of ash to bring the temps back up, engaged the cat and let them coal up. Had a very thick bed of coals.
• Increased air to heat the coal bed up, reloaded full and went to bed.
• Was awakened by the alarm @1650 several times, tried increasing air, decreasing air no success. Closed the key damper and it worked for a little while.
• Finally gave up and blocked the secondary air.... that worked.
• Woke up to a heavy coal bed, glass 80% clean. Everything seemed fine. Removed the plate and increased air to burn down the coal bed.

My mistake here was a full load on top of a very hot bed of coals. I was tired and impatient.

 

[AsylumResident]

Another rager last night....

• Yesterday I let the stove coast on a heavy bed of coals
• Loaded 2 med splits of ash to bring the temps back up, engaged the cat and let them coal up. Had a very thick bed of coals.
• Increased air to heat the coal bed up, reloaded full and went to bed.
• Was awakened by the alarm @1650 several times, tried increasing air, decreasing air no success. Closed the key damper and it worked for a little while.
• Finally gave up and blocked the secondary air.... that worked.
• Woke up to a heavy coal bed, glass 80% clean. Everything seemed fine. Removed the plate and increased air to burn down the coal bed.

My mistake here was a full load on top of a very hot bed of coals. I was tired and impatient.

View attachment 322806

This is it. This my future with this beast. Decent runs with periodic, seemingly unavoidable runaways. I understand there is an answer this occasion here but I have been struggling the last couple weeks with mine.

Right now I do not trust my stove to run without me there. She has a lot of making up to me before I'll get back to that point.

 

[Eman85]

Sorry to hear your stove still takes off like that. Mine gives me moments of anxiety where I don't trust it and then it cruises nicely. I loaded at 10PM last night and at 1100 I closed the air down like I have been doing. It was a full load and after it settled the temps did start rising. I checked it about 1AM and it was in the 1300's. I just trusted it and went back to bed. This morning cat was in the 500's and I opened the air 100% and it jumped to 700's with a large bed of coals. Checked the Auber high memory and it never went past 1350. I reloaded again this morning at about 9:30 and when it went over 1000 I cut the air back to 10% and sat and watched. Temps rose into the mid 1100's then dropped and have now rose and running at 1340. My wood is mixed with ash, walnut, oak, locust and whatever in with it. Stack was split years ago and most of the splits are less than 4".
As I posted my stove has not gone out since Jan 1.

 

[Todd]

Sorry to hear your stove still takes off like that. Mine gives me moments of anxiety where I don't trust it and then it cruises nicely. I loaded at 10PM last night and at 1100 I closed the air down like I have been doing. It was a full load and after it settled the temps did start rising. I checked it about 1AM and it was in the 1300's. I just trusted it and went back to bed. This morning cat was in the 500's and I opened the air 100% and it jumped to 700's with a large bed of coals. Checked the Auber high memory and it never went past 1350. I reloaded again this morning at about 9:30 and when it went over 1000 I cut the air back to 10% and sat and watched. Temps rose into the mid 1100's then dropped and have now rose and running at 1340. My wood is mixed with ash, walnut, oak, locust and whatever in with it. Stack was split years ago and most of the splits are less than 4".
As I posted my stove has not gone out since Jan 1.

Do you monitor flue temps? If so what are you seeing?

 

[Eman85]

i don't have a flue temp probe installed, I have one just haven't drilled the DW pipe. I have a magnetic thermometer on my stove pipe adapter so it's only 6" above the stove. It will run in the 300's with the cat engaged fully. Only time it rises is with the damper open running without the cat, it will keep rising if I don't cut cut the air. 500 on the flue I have the pipe starts stinking so that's as high as I let it run. I used to have SW on it and it would run about the same on the SW about 18" above the stove. I used to get a lot more heat in the room with the SW.

 

[arnermd]

This is it. This my future with this beast. Decent runs with periodic, seemingly unavoidable runaways. I understand there is an answer this occasion here but I have been struggling the last couple weeks with mine.

Right now I do not trust my stove to run without me there. She has a lot of making up to me before I'll get back to that point.

I hear you brother and I feel your pain. Every time I think I got it figured out... I don't. After my last rebuild I decided I was not going to let it stress me out, but it still does. My plan is to run it till it breaks and then rebuild again under warranty. When they stop honoring the warranty, I will buy another stove (not a VC).

After saying all that, when it runs right, I love it and the house is way warmer than it was when I burned dinosaurs....

First pot of beans this season cooking on the stove top! Should be good and tasty tomorrow.

Almost forgot.... You already know this, smaller loads are more controllable. I have been not packing it full (1/2 - 3/4 loads) and it is better, (but not perfect). I can still get at least 8 hours out of a burn so no need to relight with lower air settings. Although that may not work when winter actually shows up and I need more heat.

 

[AsylumResident]

I hear you brother and I feel your pain. Every time I think I got it figured out... I don't. After my last rebuild I decided I was not going to let it stress me out, but it still does. My plan is to run it till it breaks and then rebuild again under warranty. When they stop honoring the warranty, I will buy another stove (not a VC).

After saying all that, when it runs right, I love it and the house is way warmer than it was when I burned dinosaurs....

First pot of beans this season cooking on the stove top! Should be good and tasty tomorrow.

Almost forgot.... You already know this, smaller loads are more controllable. I have been not packing it full (1/2 - 3/4 loads) and it is better, (but not perfect). I can still get at least 8 hours out of a burn so no need to relight with lower air settings. Although that may not work when winter actually shows up and I need more heat.

Yeah I have been running smaller loads. The metal cat definitely acts differently than the ceramic cat. Or I have heard something of about new cats being more active when you start using them, is that true? Do they need to get broken in?

 

[arnermd]

My general opinion:

• I believe that new cats are more active and they calm down as they age.... like all of us.
• But I think yours should be broken in by now. As I recall mine calm down after 4-6 weeks.
• The metal cats are not as hyper right out of the box.

Curious to hear other opinions.

 

[AsylumResident]

My general opinion:

• I believe that new cats are more active and they calm down as they age.... like all of us.
• But I think yours should be broken in by now. As I recall mine calm down after 4-6 weeks.
• The metal cats are not as hyper right out of the box.

Curious to hear other opinions.

Got it. I've been burning with it for the last two weeks. I haven't been burning very much though.

 

[arnermd]

Todays Ash experiment.....

• Decent bed of coals, opened air to get them nice and hot. Raked coals evenly.
• Reloaded with 3/4 load of all ash, minimal bark, about 5 med splits.
• Closed the damper after few minutes to keep flue temps low.
• Cat lit off in <10 minutes, reduced air to 60% at cat = 700 (usually I wait for cat = 1000)
• At cat = 820 reduced air to 20% (usually I wait for cat = 1200)
• Turned my alarms off and let it go, no operator intervention..... YOLO.

As you can see the cat ground its way up to 1676 before deciding it had had enough......

Results: Reducing the air at lower cat temps did not seem to have any impact on peak cat temps. If I had more wood in there it probably would have gone to 1700+.

This burn coasted for another 6 hours (till 15:30 pm) with solid heat output.

 

[AsylumResident]

Todays Ash experiment.....

• Decent bed of coals, opened air to get them nice and hot. Raked coals evenly.
• Reloaded with 3/4 load of all ash, minimal bark, about 5 med splits.
• Closed the damper after few minutes to keep flue temps low.
• Cat lit off in <10 minutes, reduced air to 60% at cat = 700 (usually I wait for cat = 1000)
• At cat = 820 reduced air to 20% (usually I wait for cat = 1200)
• Turned my alarms off and let it go, no operator intervention..... YOLO.

As you can see the cat ground its way up to 1676 before deciding it had had enough......

Results: Reducing the air at lower cat temps did not seem to have any impact on peak cat temps. If I had more wood in there it probably would have gone to 1700+.

This burn coasted for another 6 hours (till 15:30 pm) with solid heat output.

View attachment 322941

My logical mind wants to say letting it burn more up front and getting hotter on the front end then reducing air would help reduce the cat temps through the burn. But we already know that doesn't always work that way.

 

[Eman85]

You keep playing with letting the cat get hot before cutting the air. I'm still cutting it back at 1,000 to 1100 and it's been very controllable. Last night I cut it back and it dropped then rose predictably, went to bed and checked this morning max temp was 1450. At 8am, 10 hers after reload, I opened the air fully and the cat rose to over 1,000 and I enjoyed 2 more hours of heat before I loaded again. Same drill reloaded, cut the air at 1050 and the stove has been running all day.

 

[arnermd]

My logical mind wants to say letting it burn more up front and getting hotter on the front end then reducing air would help reduce the cat temps through the burn. But we already know that doesn't always work that way.

I was thinking something similar. On this run I ran it with more air, thinking was I would get more primary burn and maybe less secondary...

• Very similar load to last time, 5 med splits all ash, minimal bark
• Engaged the cat at flue gas = 500
• Cut air back to 60% at cat = 500 (much lower than normal for me)
• At 16:36 the flue gas rocketed to 1400.... There was no intervention from me. This happened incredibly fast.
  • The only thing I noticed was some logs settling as I heard them drop around this time.
  • Got that plasticy smell in the house........ Stack was hot!
• Cat ground higher peaking at 1671.....
• Stove was throwing a lot of heat, too much. 87F in my room with the stove.

Conclusion: Increasing air setting did not affect peak cat temps and over heated the house....

 

[arnermd]

You keep playing with letting the cat get hot before cutting the air. I'm still cutting it back at 1,000 to 1100 and it's been very controllable. Last night I cut it back and it dropped then rose predictably, went to bed and checked this morning max temp was 1450. At 8am, 10 hers after reload, I opened the air fully and the cat rose to over 1,000 and I enjoyed 2 more hours of heat before I loaded again. Same drill reloaded, cut the air at 1050 and the stove has been running all day.

I have been cutting air at lower temps, examine the plots. In yesterdays first run I dropped air to 60% @ 600 and 20% @ 850.
On the second run (which I just posted) I cut air to 60% @ 500. Does not seem to matter.

What species are you burning?

 

[Eman85]

My loads are very mixed, it's got oak white and red, walnut, cherry, locust, ash, hickory and anything else I cut. I had a pile of wood from odds and ends downed trees and limbs I had accumulated. When I split it I just stacked it all together. They are mostly small 4" or so splits.
Last night I loaded about half at 8PM on hot coals left from the 10am reload. I did this just to keep the stove going until my 10PM full reload and temps were dropping rapidly outside. The 1/2 load came up to temp quick and at 1,000 I cut the air back to 10% and went and watched TV. Stove did it's same deal dropping then rebounding and then settling. At 10 I gave it a full load and we were at single digits outside. Let it run to 1,050 and cut it back, it fell back and then rebounded like it's been doing. Around midnite it climbed to 1470 and then slowly dropped a little as I went to bed. Checked the max on the Auber and 1480 was the max reading that it went back to. Still haven't reloaded yet, temps dropped to 0 last night. I did turn my thermostat up into the mid 70's as I wanted to keep heat in the whole house up, I'm on a crawlspace and heat ducts under floors and wanted to avoid frozen pipes. I know my heat did kick on a little.