2025/26 VC performance discussion thread

[JohnDaileyNH]

Ok that’s what I was thinking, must be the back side taking all the heat. I suppose it would be beneficial to have a rear heat shield and blower in this design. 400 external stack temp seems a little high to me? My Fireview runs 400-500 internal flue temps.

Exactly this, I run this stove and have a heat shield and blower on the back. When the stove is run with primary air in a medium-low setting the cat stays 1000 or so for hours and it puts off a very consistent heat

 

[skb31]

I’m having a sustained higher cat temp burn this evening. This reload started off normally but after about an hour the cat moved up to about 1450. It hung there for a half hour or so and now has settled to between 1375 and 1425 for a couple hours with air cut all the way.

It’s the coldest outside temps we’ve had this year, down into the upper teens and will get a bit colder. I’ll let it do its thing since the temps are still ok. No need to try the damper but I was curious if tonight was the night!

 

[Woodsplitter67]

Yeah it gets up there sometimes.. I don't worry my cat spiked the other day like1525. Nothing ever happens

 

[Smokey Da Bears]

Today's burn has me scratching my head a bit and I'm not sure if I should be or not...

Stove was cold this past Saturday and I did a minimal clean and checked the catalyst, looked totally normal. I left the ash pan full and some on the top grate but took a few scoops. I relit the stove Sunday morning and it's been burning unremarkably since then. These temps are what I would call "normal" lately for my operation which is why I say unremarkably ..... normal cat temps (1000-1350), normal STT (450-500), normal stack temps (250-350). The picture is from this morning around 6am, after loading up last night around 9:30pm. Still not enough heat in the morning to keep the stove top thermal fan running, but I've been celebrating these wins. And getting back up to temp is easier.

Cat temps today though have been way lower than what I would expect. It's a rainy dreary day here outside. There is a HUGE coal base in my stove right now, like 4 or 5 inches. And I just loaded 5 medium sized oak splits. 30 minutes after loading my Cat was only sitting at 800 at full air, STT was at 500. To experiment, I closed the air down completely and my Cat finally took off, but only to 1020 where it's just kind of hanging out over the last 30 minutes. There is very little going on in the box and the stove top is at 450. This may seem weird to say, but it feels like the stove is pushing some serious convection heat.

Based off previous experiences, I would expect to see the Cat higher - like 1200-1400 . Based on what is in the box.

I guess my only concern with this entire thing, and why I'm scratching my head, is that my stack temp (measured 18 inches above the stove with a magnetic gauge) is only at like 225. See 2nd picture....this seems low to me in comparison to what I've typically been seeing.

My plan this week was to burn the stove until Thursday morning and let it go out as I have to go into the city for work. Then on Friday, do a little house keeping, visually inspect the chimney, etc. before relighting.

Any thoughts on that external stack temp?


EDIT: About 30 minutes after posting this, my Cat temp rose to 1150 gradually across that 30 minutes. But that stack temp didn't really increase.

 

[begreen]

It looks like at that stage of the burn the cat did not have as much wood gas to chew on, thus the lower cat temp.

 

[VRB Farm]

Smokey - you mentioned the quintessential Northeast December weather of cold and rainy.... I'd bet it was the front moving through causing draft to decrease in the stack,.

Here Monday AM it was 7 degrees out with freezing fog, no wind at all, stove didn't want to draft very well at all when I closed it down which shocked me with the temp being so low, gave some extra air to keep the cat and draft happy. As soon as the sun came up and the outside air started mixing things acted normal. I am quickly learning that my chimney stack isn't tall enough after deduction in footage for (2) 90's in the pipe, but then I also get over draft on a high southwestern winds because of the open field. Pick our battles I guess.

 

[Smokey Da Bears]

Smokey - you mentioned the quintessential Northeast December weather of cold and rainy.... I'd bet it was the front moving through causing draft to decrease in the stack,.

Here Monday AM it was 7 degrees out with freezing fog, no wind at all, stove didn't want to draft very well at all when I closed it down which shocked me with the temp being so low, gave some extra air to keep the cat and draft happy. As soon as the sun came up and the outside air started mixing things acted normal. I am quickly learning that my chimney stack isn't tall enough after deduction in footage for (2) 90's in the pipe, but then I also get over draft on a high southwestern winds because of the open field. Pick our battles I guess.

Yeah I guess Scientifically this aligns…it’s colder now than it was this afternoon by about 10 degrees, still raining kind of slushy. I reloaded about an hour ago and I’m cruising at a cat temp of 1200. Stack temp almost 300. So higher temps than earlier which I’m understanding as better.

So if stack temps are low like that but you have what appears to be an efficient burn - are you still “gunking up a pipe”? I couldn’t honestly tell if I had smoke at the exhaust, the weather was crap and the sky was too gray.

 

[Turbo89]

Yeah I guess Scientifically this aligns…it’s colder now than it was this afternoon by about 10 degrees, still raining kind of slushy. I reloaded about an hour ago and I’m cruising at a cat temp of 1200. Stack temp almost 300. So higher temps than earlier which I’m understanding as better.

So if stack temps are low like that but you have what appears to be an efficient burn - are you still “gunking up a pipe”? I couldn’t honestly tell if I had smoke at the exhaust, the weather was crap and the sky was too gray.

I’ve noticed the same thing with my encore the last few days, which I’ve attributed to weather / draft. It’s been sort of warm and with low cloud cover. On Sunday I had one full load that barely saw CAT temps of 900; but there was plenty of heat, so no issue. My flue is about 18’ straight up through the roof.

 

[skb31]

Do you have an IR gun that’s reliable @Smokey Da Bears? I’m curious if your bimetal gauge is off or perhaps it’s the placement. I assume you have your stove pipe gauge where it is to make it easier to read. I wonder if moving it to the top of the bend would make it read a bit warmer.

My guess is that at 1200 cat temp, your stove pipe temp is warmer than that meter is showing you.

Right now my cat temp is 1186, stove pipe is ~350, stove top is 480. My stove top temp always rises in the later stage of the burn and I would agree with your previous statement above convective heat when it comes to this later stage.

 

[Smokey Da Bears]

I actually have 2 bimetal gauges on my black pipe. The one in the pictures is about 18 inches up right at a 45 after the oval to round . The other one is about 30 inches past that prior to a 90 where I then meet up with a thimble to go out the house. I find the 2nd one to run hotter by about 50 degrees, and I've never "fully" trusted that one, mostly because it's a cheap Amazon thing that I probably should have threw away 3 years ago. Yesterday they were both on the lower side and correlated (+/- 50 degrees). I do have an IR gun that I often forget I have. I'll pull that out and give it a look.

I had a nice insulated bed of coals this morning from a 7pm load up last night. Cat temp was only 180, stove top about 150. Warm to the touch but not throwing any significant heat. Stove is in our basement with a central staircase, we leave the door open and run a small fan pointing back down the stairs. 1st floor was 72 last night when I went to bed. It was 67 at 5am this morning. It's a lot colder out this morning, high 20s/low 30s. Restart was very easy with a sheet of paper, sticks, and some small pieces. Added some small to medium splits and burning those down now before loading up and getting off and running.

Hope to have similar results today and into tomorrow morning, but sadly need to go in to the city tomorrow for work. So the stove will go cold tomorrow. Looks like we'll see some cold outside temps in the 10-20 degree range over the next week.

 

[Woodsplitter67]

22 degrees this morning when I woke up. House super comfortable. I loaded the stove last night a little before,7 pm. At 5.30 am my cat temperature was still in the active range at 562 and had a ton of coals going on. Definitely had more then another hour or so of actual good heat from this burn.

The box was loaded with thick split oak

 

[Smokey Da Bears]

Stove is relit after a commute to the city yesterday and we're all happy again. The oil heat just isn't the same - granted I only set it to 64. When I got home last evening everybody had a few extra layers on 😂🤣. Took a while to get that coal base built again but we're cruising and 1st floor temp is 70 again. Cat popped up to 1320 on this load of maple. The smell of that is pretty pleasant in comparison to Oak, it's got a sweetness to it.

 

[Turbo89]

Yesterday and overnight were in the teens here, here’s how she the encore ran:

Reload at about 7:30 last night

About 14-1/2hrs later, burning just a crack past full closed:

Building back up a coal base now:

 

[Turbo89]

Tonight’s reload, 1 piece of ash, 3 large mystery heavy/stringy splits, and 1 small piece of maple to fill the right side gap.

Let’s see how she burns overnight:

When I walked away the cat still hadn’t crossed 1000, but it was starting to off gas, I’m guessing it’ll creep up over the next hr or 2. Air is just a crack past full-closed.

 

[skb31]

My hot reload before bed last night saw the cat temps take off for a bit. I reached a peak of 1613 about 30 mins into the burn cycle. About an hour in the temp was down to the low 1500s and then on last check at about 90 minutes in it was mid 1450s. Primary air is cut and stove is doing its thing so season 3 version of me just rides it out.

Outside of the cat chamber probe there is nothing that indicates a high temperature when mine occasionally runs hot for these short periods. Stove top temp was around 375 and flue pipe temp meter never hit 400 at the peak of the cat temp. I double checked the placement of the cat probe and it was positioned correctly. Out of an abundance of caution, this morning I made sure the primary air flapper was closing correctly and of course it was.

I think the digital meter and probe are critical for me to know how the stove is running, however, if I didn’t have it I wouldn’t have known about or suspected high cat temps. There was minimal flame in the box and everything else looked ok.

I share these more notable experiences just in case others need something to relate to.

 

[Turbo89]

Overnight burn did pretty well last night, came out to a bunch of coals and some flames still about 11 hrs later.