2013 VC Burning Thread

[grobinson2]

Okay, so last night was a long night. I am running the stove with the cat. Loaded it about as full, as I could get it with a mix of oak and birch. A piece or two is very very dry and about five years old and the rest was cut two years ago and split this year. I ran the stove up to 550 in bypass mode and then closed the damper with my primary air intake all the way open. Once my cat probe was up to 1000F I closed down the air. The cat went to 1650 in seconds and the stove top went to 600. I opened the bypass with my primary air still shutdown to drop my cat temp but the stove took off like a blast furnace in seconds and I was afraid of starting a chimney fire (I am running a 35 foot brick chimney without any liner that needs a liner and will get one this summer) so I closed the damper and watched the cat go back to 1600F again. This time I opened up my clean out door on the bottom of the chimney to kill my draft and I was able after two or three hours to get the cat temp down to 1300F. Even with the cat temps in that range the stove stayed at a nice 500F. This morning all was well and other then being a little tired the house was nice and warm and the stove was still at 300F (griddle temp) with lots of coals still glowing. I closed my clean-out port on the chimney, loaded the stove about half way with the same mix and let it get up to 500F at which time I closed the damper and went into cat mode. 400 to 800F cat temp went in about eight min but that was about it. I was able to get the cat temp up to 1K but was still getting smoke out the chimney. Any ideas?

Thanks,
Glenn

 

[Excavator]

I never can wait that long to close bypass. When my griddle temp hits 350 - 400 I have to close bypass and then the cat probe starts to show temps at 350 and climbs quickly with air wide open. If I keep the bypass open even a minute too long the cat temps go too high when bypass closed.
I may have some minor smoke first few minutes after cat engaged but it clears up nice

 

[jharkin]

I don't use griddle temp anymore. If the stove is coming up from cold it can lag flue temps considerably.... I have a surface flue temp thermo on the single wall pipe right at the flue collar. As soon as that hits 400 I can engage and get a reliable light off.

 

[grobinson2]

I have one on the pipe as well and will use that from now on. I like your point about it being quicker to react then the griddle temp.

Thanks,
Glenn

 

[Reckless]

I don't use griddle temp anymore. If the stove is coming up from cold it can lag flue temps considerably.... I have a surface flue temp thermo on the single wall pipe right at the flue collar. As soon as that hits 400 I can engage and get a reliable light off.

This is exactly what I do also. GT are more for me to know if Im utilizing the load effectively (for me anyway).

 

[GJUL]

1st - thanks for the wealth of info all …. 2nd -- I'm on my second season with a new Defiant and my Cat looks like the pic attached. I've not been using a cat probe, so can't speak to what's been going on there, but I'm betting that the pic will tell some of you the story! Should I simply run without it in place until I get a new one? Or am I better off using this one until replaced?

Thanks for any input offered.

 

[jharkin]

I havent had it happen myself, but that looks like photos Ive seen of thermal shock cracking.

Leave it in till you get a new one. Even if its lost a lot of effectiveness you are still burning cleaner and more efficient than just running on bypass. As long as you see the smoke out of the stack decrease after you engage it you know its doing something.

 

[GJUL]

Thanks for the quick reply JHarkin --- anxious to get a fire going again tonight and will search on 'Thermal shock cracking' next.

 

[Charles1981]

This is my cat after 1.5 seasons. No noticeable damage last season. No noticeable damage this past turkey day. I pulled it about 2 weeks ago during a sweep and had a crack with the center metal piece warped. Still running as normal, but a little disappointing.

 

[Diabel]

1st - thanks for the wealth of info all …. 2nd -- I'm on my second season with a new Defiant and my Cat looks like the pic attached. I've not been using a cat probe, so can't speak to what's been going on there, but I'm betting that the pic will tell some of you the story! Should I simply run without it in place until I get a new one? Or am I better off using this one until replaced?

Thanks for any input offered.View attachment 126253

Yup, this cat is toast. My understanding of the "2in1" was that you can run it with or without the cat in place.
Without the cat the stove is to run as the "everburn" system, still very efficient as per VC apparently....

I could be wrong however.

 

[BrowningBAR]

Yup, this cat is toast. My understanding of the "2in1" was that you can run it with or without the cat in place.
Without the cat the stove is to run as the "everburn" system, still very efficient as per VC apparently....

I could be wrong however.

You are correct if this is a 2-in-1 model.

 

[R2.0]

Hello all. I did a search and didn't find any Winterwarm references, so I figured my questions may not have been asked a million times already.

I got my secondhand Winterwarm Large installed about 3 weeks ago: installation and startup. I'm having trouble with the operation, or at least I think I am. Here are the basics:

• New 8" flexible liner installed with Thermix in masonry chimney
• Fuel is a 60:40 mix of oak and poplar - slab wood from a local mill. Haven't done the moisture content, but logs were seasoned before the cuts and the wood had been sitting from 6 months to 2 years.
• No air leaks in the body, but some around the door - my attempts at evening out the stove face didn't work out so well.
• Catalyst was a bit swelled, but still fit in the refractory fine.
• Chimney temp via surface mount thermocouple about 10" from the stove collar
• Catalyst temp via an inconel thermocouple in the factory location.

Can someone give me some basic operational guidance? I owned a Quadrafire 4100 for a few years and got decent at operating the primary and secondary air controls, and it threw out a ton of heat. But for a stove of similar size I'm having a hard time getting the Winterwarm to acceptable output. My current SOP is:

1. Using a paraffin/egg carton firestarter, some poplar, and a couple pieces of oak, start the fire. I don't really need "kindling" per se - the poplar and even the oak lights right off.
2. Run with door cracked until the fire has gotten established - about 5 minutes - then close the door with the primary air control fully open.
3. Feed fuel until a decent bed of coals is established, say 1"-2".
4. Close the bypass damper.

When I close the damper, the draft drops markedly, but I'm not getting smoke out of the chimney. Initially it seemed I couldn't get the catalyst to light off at all, but for the last 2-3 firings i've gotten it to run at about 800f-900f, with an occasional excursion to 1500F. But I can't seem to get it to throw a lot of heat. Theories are:

- Bad fans. They are turning, but the airflow seems to be minimal. Is this the way it's supposed to be?
- Partially plugged/bad catalyst.
- Operator error
​

Obviously I'm hoping for the last - that's cheap to fix. With my luck it will be all 3.

Any ideas?

 

[grobinson2]

I second BrowningBAR and have run mine with out the cat in with good results. That said the longer I run the stove the better I am getting and using the cat is more efficient (as we already know).

Thanks,
Glenn

 

[R2.0]

Unless I am wrong was this meant for a different forum?

Glenn

Umm, nope - it is a Vermont Castings unit. But if I missed the intent of the thread I apologize and can delete it.

 

[jharkin]

R2.0 - This thread is open for any vermont castings discussion, its just happens to be dominated by freestanding stove owners. Please do stick around, the more the merrier

EDITED: Missed that your insert was catalytic...

 

[R2.0]

R2.0 - This thread is open for any vermont castings discussion, its just happens to be dominated by catalytic talk so faras there seems to be more VC cat stoves in circulation than noncats. Please do stick around, the more the merrier

It does seem like you can't swing a dead cat around here without hitting...a dead cat.

 

[jharkin]

i updated my reply, i didnt realize your winterwarm was a cat insert.

 

[jharkin]

Can someone give me some basic operational guidance? I owned a Quadrafire 4100 for a few years and got decent at operating the primary and secondary air controls, and it threw out a ton of heat. But for a stove of similar size I'm having a hard time getting the Winterwarm to acceptable output. My current SOP is:

1. Using a paraffin/egg carton firestarter, some poplar, and a couple pieces of oak, start the fire. I don't really need "kindling" per se - the poplar and even the oak lights right off.
2. Run with door cracked until the fire has gotten established - about 5 minutes - then close the door with the primary air control fully open.
3. Feed fuel until a decent bed of coals is established, say 1"-2".
4. Close the bypass damper.

When I close the damper, the draft drops markedly, but I'm not getting smoke out of the chimney. Initially it seemed I couldn't get the catalyst to light off at all, but for the last 2-3 firings i've gotten it to run at about 800f-900f, with an occasional excursion to 1500F. But I can't seem to get it to throw a lot of heat. Theories are:

- Bad fans. They are turning, but the airflow seems to be minimal. Is this the way it's supposed to be?
- Partially plugged/bad catalyst.
- Operator error
​

Obviously I'm hoping for the last - that's cheap to fix. With my luck it will be all 3.

Any ideas?

OK, I did a 5 minute skim of your other threads. Looks like internally your stove is the same as the rest of us Encore/Defiant folks, just packaged into an instert. So hopefully we should be able to help you reason things out here.

• First thing to check is always the wood quality. I know you mentioned using slab wood, but assume it didn't season at all in log form. Unless its been cut into slabs over a year Id go down to the orange box, buy a $20 moisture meter, re-split a piece and check. If you get readings over 25% we should suspect the wood.
• Alternative wood test: go to a supermarket and buy a couple of those kiln dried bundles. If those burn hot also makes your wood suspect.

If the wood is the issue you might get some of those eco log products or look for pallet wood to mix in.

• If the wood checks out OK, yes I would suspect the catalyst is bad. These VC stoves tend to burn hyperactive, when mine is working well its actually quite a struggle to keep those probe temperatures below 1000F. If its sits at low 800ish temps I suspect a stall, go back on bypass and get the fire hotter then try again.
• On the blowers I cant say, no experience there. Do you know if they are thermostatically controlled? If yes might just be the instert isn't getting hot enough to trigger high blower (due to the above).

Your burn routine looks decent. On a cold start-up I use 1/4 of a supercedar between 2 splits and some kindling on top, then once established add a couple more small splits and let it burn till the single wall flue pipe at the collar hits 400-450. Then I close the bypass and watch the probe temp for lightoff. I dont go right for a full load on a cold start, on the next reload with a good coal bed I will pack it full and then burn wide open and again shut bypass around 400 on the single wall. This usually works well and then once the cat hits 1000F i slowly close down the air over 10-15min. The only difference for you is you probably cant watch flue temps....

 

[Charles1981]

So how does this 2in1 work exactly? There certainly aren't other cat stove out there that are advertised to run with or without it installed.

If the cat is degrading or not working there is an obvious obstruction in the chamber to allow normal flow for the stove to run in E(n)everburn mode, but is it then working hybrid?! lol. I take it in non-cat setup they are still expecting a secondary burn in the chamber just with the cat removed? Maybe this is why the cats degrade so fast in some stoves, the temps in the chamber are actually remarkably higher than normal due to secondary burn initiating without cat?

I really don't know what I am talking about in this, and so am having some trouble wrapping my mind around how the stove still burns secondaries with or without the cat installed.

And in the above posters post with the holes in the cat...i mean some of the cat is still probably getting active? Is he still experiencing 2nd burn in the chamber due to the fact that stove is still marked to burn secondaries with the cat removed, or is the cat creating some obstruction to prevent that from occurring.

 

[R2.0]

OK, I did a 5 minute skim of your other threads. Looks like internally your stove is the same as the rest of us Encore/Defiant folks, just packaged into an instert. So hopefully we should be able to help you reason things out here.

• First thing to check is always the wood quality. I know you mentioned using slab wood, but assume it didn't season at all in log form. Unless its been cut into slabs over a year Id go down to the orange box, buy a $20 moisture meter, re-split a piece and check. If you get readings over 25% we should suspect the wood.
• Alternative wood test: go to a supermarket and buy a couple of those kiln dried bundles. If those burn hot also makes your wood suspect.

If the wood is the issue you might get some of those eco log products or look for pallet wood to mix in.

• If the wood checks out OK, yes I would suspect the catalyst is bad. These VC stoves tend to burn hyperactive, when mine is working well its actually quite a struggle to keep those probe temperatures below 1000F. If its sits at low 800ish temps I suspect a stall, go back on bypass and get the fire hotter then try again.
• On the blowers I cant say, no experience there. Do you know if they are thermostatically controlled? If yes might just be the instert isn't getting hot enough to trigger high blower (due to the above).

Your burn routine looks decent. On a cold start-up I use 1/4 of a supercedar between 2 splits and some kindling on top, then once established add a couple more small splits and let it burn till the single wall flue pipe at the collar hits 400-450. Then I close the bypass and watch the probe temp for lightoff. I dont go right for a full load on a cold start, on the next reload with a good coal bed I will pack it full and then burn wide open and again shut bypass around 400 on the single wall. This usually works well and then once the cat hits 1000F i slowly close down the air over 10-15min. The only difference for you is you probably cant watch flue temps....

I actually can watch flue temps. I bought this thermometer, which came with 2 Type K bare thermocouples. I clamped one to the chimney liner with a SS HVAC worm drive clamp, and used the connector for the other thermocouple that I bought separately for the cat. As soon as I get some extension wire I can leave the probes plugged in and switch between both channels.

It sounds like you are using 400F as the setpoint to close the bypass and are trying to modulate the cat temp at 1000F - correct?

I'll see if I can pick up a wood moisture meter today.

(Btw my ultimate goal is to use a PLC to control the primary and secondary air, as well as setpoint/alarm. That's why I went with component probes instead of the Condar unit. And it was half the price.)

 

[jharkin]

I'm reading 400 on the single wall pipe surface as a guide to close the bypass as I've found this works through trial and error. Actual flue gas temp is higher of course.... With your probe readings maybe try 600. And if that works ok next time try 550.. And on till you find the lowest temp that will achieve light off.


The 1000 figure is just a sign that the catalytic burn is well established. Mine will typically cruise anywhere from 1200 to 1500. Spikes to 1700 or more are possible with dry wood if you are not carefull. The mfg specs 1700 as the max safe temp.

 

[Charles1981]

So (basically answered half of my own question earlier) I found this thread regarding non-cat everburn stoves. It seems very in depth regarding the function of how the coal bed and 2nd burn chamber are supposed to work.

https://www.hearth.com/talk/threads...-cat-owners-discussion-and-review-thread.3386

It doesn't answer how the everburn system work in combination with sticking a cat in there.

 

[BrowningBAR]

I second BrowningBAR and have run mine with out the cat in with good results. That said the longer I run the stove the better I am getting and using the cat is more efficient (as we already know).

Thanks,
Glenn

Yours is the current generation 2-in-1 and when you run it without the cat, you remove that cat, but still have the damper closed, right? Just making sure we are on the same page, otherwise you can damage the stove.

 

[BrowningBAR]

So how does this 2in1 work exactly? There certainly aren't other cat stove out there that are advertised to run with or without it installed.

The concept is that the assembly without the cat, runs like the everburn system. With the cat it runs like a cat stove. I have never run the newer 2-in-1 stoves and I have never operated a non-cat everburn VC stove, so, I can not go into how the everburn system creates a secondary combustion.

 

[R2.0]

So last night I tried lighting off the cat earlier than I did before and it works pretty well. I ran it on bypass for the first small load and engaged the cat on the second. With the damper wide open the cat heated up steadily from about 500 to 1200, where I started to throttle it back, but I was behind the curve and opened the bypass when it hit about 1400. I repeated that process a few times, with a couple of reloads, and started to home in on cruising in the 1300's.

And here's where I discovered I'm an idiot - I had the fan controls reversed. Apparently the fan lever goes OFF: HIGH------->LOW, not OFF:LOW------>HIGH. So I had been running the fan at minimum speed. :| When I started running the fan at high speed the cat temp started to slowly fall, which I think is due to increased heat transfer. This should also make the stove temperatures easier to control.

Question: what rate of temperature increase is considered dangerous? I was getting at most about 50F/minute.